diff --git a/src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version2_X/test/IntegrationTests/InstrumentationPassIntegrationTest.cs b/src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version2_X/test/IntegrationTests/InstrumentationPassIntegrationTest.cs
index 77a5e4f75a1..322997c72f2 100644
--- a/src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version2_X/test/IntegrationTests/InstrumentationPassIntegrationTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions.Version2_X/test/IntegrationTests/InstrumentationPassIntegrationTest.cs
@@ -31,36 +31,36 @@ public InstrumentationPassIntegrationTest()
     public void BasicTest()
     {
         // Arrange
-        var descriptors = new[]
-        {
-                CreateTagHelperDescriptor(
-                    tagName: "p",
-                    typeName: "PTagHelper",
-                    assemblyName: "TestAssembly"),
-                CreateTagHelperDescriptor(
-                    tagName: "form",
-                    typeName: "FormTagHelper",
-                    assemblyName: "TestAssembly"),
-                CreateTagHelperDescriptor(
-                    tagName: "input",
-                    typeName: "InputTagHelper",
-                    assemblyName: "TestAssembly",
-                    attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                    {
-                        builder => builder
-                            .Name("value")
-                            .PropertyName("FooProp")
-                            .TypeName("System.String"),      // Gets preallocated
-                        builder => builder
-                            .Name("date")
-                            .PropertyName("BarProp")
-                            .TypeName("System.DateTime"),    // Doesn't get preallocated
-                    })
-            };
+        TagHelperCollection tagHelpers =
+        [
+            CreateTagHelperDescriptor(
+                tagName: "p",
+                typeName: "PTagHelper",
+                assemblyName: "TestAssembly"),
+            CreateTagHelperDescriptor(
+                tagName: "form",
+                typeName: "FormTagHelper",
+                assemblyName: "TestAssembly"),
+            CreateTagHelperDescriptor(
+                tagName: "input",
+                typeName: "InputTagHelper",
+                assemblyName: "TestAssembly",
+                attributes:
+                [
+                    builder => builder
+                        .Name("value")
+                        .PropertyName("FooProp")
+                        .TypeName("System.String"),      // Gets preallocated
+                    builder => builder
+                        .Name("date")
+                        .PropertyName("BarProp")
+                        .TypeName("System.DateTime"),    // Doesn't get preallocated
+                ])
+        ];
 
         var engine = CreateProjectEngine(b =>
         {
-            b.AddTagHelpers(descriptors);
+            b.SetTagHelpers(tagHelpers);
             b.Features.Add(new InstrumentationPass());
 
                 // This test includes templates
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperBlockRewriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperBlockRewriterTest.cs
index 0f8aaf1d83e..6ffcfd2aa46 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperBlockRewriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperBlockRewriterTest.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Globalization;
 using Microsoft.AspNetCore.Razor.Language.Components;
 using Xunit;
@@ -12,7 +11,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy;
 
 public class TagHelperBlockRewriterTest : TagHelperRewritingTestBase
 {
-    public static ImmutableArray<TagHelperDescriptor> SymbolBoundAttributes_Descriptors =
+    public static readonly TagHelperCollection SymbolBoundAttributes_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("CatchAllTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -48,46 +47,46 @@ public class TagHelperBlockRewriterTest : TagHelperRewritingTestBase
     [Fact]
     public void CanHandleSymbolBoundAttributes1()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<ul bound [item]='items'></ul>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<ul bound [item]='items'></ul>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes2()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<ul bound [(item)]='items'></ul>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<ul bound [(item)]='items'></ul>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes3()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<button bound (click)='doSomething()'>Click Me</button>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<button bound (click)='doSomething()'>Click Me</button>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes4()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<button bound (^click)='doSomething()'>Click Me</button>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<button bound (^click)='doSomething()'>Click Me</button>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes5()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<template bound *something='value'></template>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<template bound *something='value'></template>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes6()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<div bound #localminimized></div>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<div bound #localminimized></div>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes7()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<div bound #local='value'></div>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<div bound #local='value'></div>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> WithoutEndTag_Descriptors =
+    public static readonly TagHelperCollection WithoutEndTag_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -99,34 +98,34 @@ public void CanHandleSymbolBoundAttributes7()
     [Fact]
     public void CanHandleWithoutEndTagTagStructure1()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure2()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input type='text'>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input type='text'>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure3()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input><input>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input><input>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure4()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input type='text'><input>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input type='text'><input>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure5()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<div><input><input></div>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<div><input><input></div>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> GetTagStructureCompatibilityDescriptors(TagStructure structure1, TagStructure structure2)
+    public static TagHelperCollection GetTagStructureCompatibilityTagHelpers(TagStructure structure1, TagStructure structure2)
     {
         return
         [
@@ -147,87 +146,87 @@ public static ImmutableArray<TagHelperDescriptor> GetTagStructureCompatibilityDe
     public void AllowsCompatibleTagStructures1()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.Unspecified);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.Unspecified);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input></input>");
+        EvaluateData(tagHelpers, "<input></input>");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures2()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.Unspecified);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.Unspecified);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input />");
+        EvaluateData(tagHelpers, "<input />");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures3()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.WithoutEndTag);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.WithoutEndTag);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input type='text'>");
+        EvaluateData(tagHelpers, "<input type='text'>");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures4()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.WithoutEndTag, TagStructure.WithoutEndTag);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.WithoutEndTag, TagStructure.WithoutEndTag);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input><input>");
+        EvaluateData(tagHelpers, "<input><input>");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures5()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.NormalOrSelfClosing);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.NormalOrSelfClosing);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input type='text'></input>");
+        EvaluateData(tagHelpers, "<input type='text'></input>");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures6()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.WithoutEndTag);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.WithoutEndTag);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input />");
+        EvaluateData(tagHelpers, "<input />");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures7()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.NormalOrSelfClosing, TagStructure.Unspecified);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.NormalOrSelfClosing, TagStructure.Unspecified);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input />");
+        EvaluateData(tagHelpers, "<input />");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures8()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.WithoutEndTag, TagStructure.Unspecified);
+        var tagHelpers = GetTagStructureCompatibilityTagHelpers(TagStructure.WithoutEndTag, TagStructure.Unspecified);
 
         // Act & Assert
-        EvaluateData(descriptors, "<input></input>");
+        EvaluateData(tagHelpers, "<input></input>");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures_DirectiveAttribute_SelfClosing()
     {
         // Arrange
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateEventHandler("InputTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -239,14 +238,14 @@ public void AllowsCompatibleTagStructures_DirectiveAttribute_SelfClosing()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, "<input @onclick=\"@test\"/>");
+        EvaluateData(tagHelpers, "<input @onclick=\"@test\"/>");
     }
 
     [Fact]
     public void AllowsCompatibleTagStructures_DirectiveAttribute_Void()
     {
         // Arrange
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateEventHandler("InputTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -258,7 +257,7 @@ public void AllowsCompatibleTagStructures_DirectiveAttribute_Void()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, "<input @onclick=\"@test\">");
+        EvaluateData(tagHelpers, "<input @onclick=\"@test\">");
     }
 
     [Fact]
@@ -429,7 +428,7 @@ public void CreatesErrorForMalformedTagHelper8()
         RunParseTreeRewriterTest("<str<strong></p></strong>", "strong", "p");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> CodeTagHelperAttributes_Descriptors =
+    public static readonly TagHelperCollection CodeTagHelperAttributes_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("PersonTagHelper", "personAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("person"))
@@ -451,79 +450,79 @@ public void CreatesErrorForMalformedTagHelper8()
     [Fact]
     public void UnderstandsMultipartNonStringTagHelperAttributes()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"(() => 123)()\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"(() => 123)()\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes1()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes2()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person birthday=\"DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person birthday=\"DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes3()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"@DateTime.Now.Year\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"@DateTime.Now.Year\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes4()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\" @DateTime.Now.Year\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\" @DateTime.Now.Year\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes5()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person name=\"John\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person name=\"John\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes6()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person name=\"Time: @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person name=\"Time: @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes7()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"1 + @value + 2\" birthday='(bool)@Bag[\"val\"] ? @@DateTime : @DateTime.Now'/>");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"1 + @value + 2\" birthday='(bool)@Bag[\"val\"] ? @@DateTime : @DateTime.Now'/>");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes8()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes9()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @@ @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @@ @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes10()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"@@BoundStringAttribute\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"@@BoundStringAttribute\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes11()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"@@@(11+1)\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"@@@(11+1)\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes12()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"@{flag == 0 ? 11 : 12}\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"@{flag == 0 ? 11 : 12}\" />");
     }
 
     [Fact]
@@ -838,7 +837,7 @@ public void UnderstandsEmptyAttributeTagHelpers5()
         RunParseTreeRewriterTest("<p class1=''class2=\"\"class3= />", "p");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> EmptyTagHelperBoundAttribute_Descriptors =
+    public static readonly TagHelperCollection EmptyTagHelperBoundAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("mythTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("myth"))
@@ -856,85 +855,85 @@ public void UnderstandsEmptyAttributeTagHelpers5()
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes1()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes2()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    true' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    true' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes3()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    ' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes4()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound=''  bound=\"\" />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound=''  bound=\"\" />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes5()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound=' '  bound=\"  \" />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound=' '  bound=\"  \" />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes6()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='true' bound=  />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='true' bound=  />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes7()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound= name='' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound= name='' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes8()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound= name='  ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound= name='  ' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes9()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='true' name='john' bound= name= />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='true' name='john' bound= name= />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes10()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth BouND='' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth BouND='' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes11()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth BOUND=''    bOUnd=\"\" />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth BOUND=''    bOUnd=\"\" />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes12()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth BOUND= nAMe='john'></myth>");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth BOUND= nAMe='john'></myth>");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes13()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    @true  ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    @true  ' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes14()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    @(true)  ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    @(true)  ' />");
     }
 
     [Fact]
@@ -1250,7 +1249,7 @@ public void GeneratesExpectedOutputForUnboundDataDashAttributes_Block7()
         RunParseTreeRewriterTest(document, "input");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> MinimizedAttribute_Descriptors =
+    public static readonly TagHelperCollection MinimizedAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -1306,7 +1305,7 @@ public void UnderstandsMinimizedAttributes_Document1()
         var document = "<input unbound-required />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1316,7 +1315,7 @@ public void UnderstandsMinimizedAttributes_Document2()
         var document = "<p bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1326,7 +1325,7 @@ public void UnderstandsMinimizedAttributes_Document3()
         var document = "<input bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1336,7 +1335,7 @@ public void UnderstandsMinimizedAttributes_Document4()
         var document = "<input bound-required-int />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1346,7 +1345,7 @@ public void UnderstandsMinimizedAttributes_Document5()
         var document = "<p bound-int></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1356,7 +1355,7 @@ public void UnderstandsMinimizedAttributes_Document6()
         var document = "<input int-dictionary/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1366,7 +1365,7 @@ public void UnderstandsMinimizedAttributes_Document7()
         var document = "<input string-dictionary />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1376,7 +1375,7 @@ public void UnderstandsMinimizedAttributes_Document8()
         var document = "<input int-prefix- />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1386,7 +1385,7 @@ public void UnderstandsMinimizedAttributes_Document9()
         var document = "<input string-prefix-/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1396,7 +1395,7 @@ public void UnderstandsMinimizedAttributes_Document10()
         var document = "<input int-prefix-value/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1406,7 +1405,7 @@ public void UnderstandsMinimizedAttributes_Document11()
         var document = "<input string-prefix-value />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1416,7 +1415,7 @@ public void UnderstandsMinimizedAttributes_Document12()
         var document = "<input int-prefix-value='' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1426,7 +1425,7 @@ public void UnderstandsMinimizedAttributes_Document13()
         var document = "<input string-prefix-value=''/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1436,7 +1435,7 @@ public void UnderstandsMinimizedAttributes_Document14()
         var document = "<input int-prefix-value='3'/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1446,7 +1445,7 @@ public void UnderstandsMinimizedAttributes_Document15()
         var document = "<input string-prefix-value='some string' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1456,7 +1455,7 @@ public void UnderstandsMinimizedAttributes_Document16()
         var document = "<input unbound-required bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1466,7 +1465,7 @@ public void UnderstandsMinimizedAttributes_Document17()
         var document = "<p bound-int bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1476,7 +1475,7 @@ public void UnderstandsMinimizedAttributes_Document18()
         var document = "<input bound-required-int unbound-required bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1486,7 +1485,7 @@ public void UnderstandsMinimizedAttributes_Document19()
         var document = "<p bound-int bound-string bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1496,7 +1495,7 @@ public void UnderstandsMinimizedAttributes_Document20()
         var document = "<input unbound-required class='btn' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1506,7 +1505,7 @@ public void UnderstandsMinimizedAttributes_Document21()
         var document = "<p bound-string class='btn'></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1516,7 +1515,7 @@ public void UnderstandsMinimizedAttributes_Document22()
         var document = "<input class='btn' unbound-required />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1526,7 +1525,7 @@ public void UnderstandsMinimizedAttributes_Document23()
         var document = "<p class='btn' bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1536,7 +1535,7 @@ public void UnderstandsMinimizedAttributes_Document24()
         var document = "<input bound-required-string class='btn' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1546,7 +1545,7 @@ public void UnderstandsMinimizedAttributes_Document25()
         var document = "<input class='btn' bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1556,7 +1555,7 @@ public void UnderstandsMinimizedAttributes_Document26()
         var document = "<input bound-required-int class='btn' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1566,7 +1565,7 @@ public void UnderstandsMinimizedAttributes_Document27()
         var document = "<p bound-int class='btn'></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1576,7 +1575,7 @@ public void UnderstandsMinimizedAttributes_Document28()
         var document = "<input class='btn' bound-required-int />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1586,7 +1585,7 @@ public void UnderstandsMinimizedAttributes_Document29()
         var document = "<p class='btn' bound-int></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1597,7 +1596,7 @@ public void UnderstandsMinimizedAttributes_Document30()
         var document = $"<input class='{expressionString}' bound-required-int />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1608,7 +1607,7 @@ public void UnderstandsMinimizedAttributes_Document31()
         var document = $"<p class='{expressionString}' bound-int></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1619,7 +1618,7 @@ public void UnderstandsMinimizedAttributes_Document32()
         var document = $"<input    bound-required-int class='{expressionString}'   bound-required-string class='{expressionString}'  unbound-required  />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1630,7 +1629,7 @@ public void UnderstandsMinimizedAttributes_Document33()
         var document = $"<p    bound-int class='{expressionString}'   bound-string class='{expressionString}'  bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1643,7 +1642,7 @@ public void UnderstandsMinimizedAttributes_Block1()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1656,7 +1655,7 @@ public void UnderstandsMinimizedAttributes_Block2()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1669,7 +1668,7 @@ public void UnderstandsMinimizedAttributes_Block3()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1682,7 +1681,7 @@ public void UnderstandsMinimizedAttributes_Block4()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1695,7 +1694,7 @@ public void UnderstandsMinimizedAttributes_Block5()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1708,7 +1707,7 @@ public void UnderstandsMinimizedAttributes_Block6()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1721,7 +1720,7 @@ public void UnderstandsMinimizedAttributes_Block7()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1734,7 +1733,7 @@ public void UnderstandsMinimizedAttributes_Block8()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1747,7 +1746,7 @@ public void UnderstandsMinimizedAttributes_Block9()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1760,7 +1759,7 @@ public void UnderstandsMinimizedAttributes_Block10()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1773,7 +1772,7 @@ public void UnderstandsMinimizedAttributes_Block11()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1786,7 +1785,7 @@ public void UnderstandsMinimizedAttributes_Block12()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1799,7 +1798,7 @@ public void UnderstandsMinimizedAttributes_Block13()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1812,7 +1811,7 @@ public void UnderstandsMinimizedAttributes_Block14()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1825,7 +1824,7 @@ public void UnderstandsMinimizedAttributes_Block15()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1838,7 +1837,7 @@ public void UnderstandsMinimizedAttributes_Block16()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1851,7 +1850,7 @@ public void UnderstandsMinimizedAttributes_Block17()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1864,7 +1863,7 @@ public void UnderstandsMinimizedAttributes_Block18()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1877,7 +1876,7 @@ public void UnderstandsMinimizedAttributes_Block19()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1890,7 +1889,7 @@ public void UnderstandsMinimizedAttributes_Block20()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1903,7 +1902,7 @@ public void UnderstandsMinimizedAttributes_Block21()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1916,7 +1915,7 @@ public void UnderstandsMinimizedAttributes_Block22()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1929,7 +1928,7 @@ public void UnderstandsMinimizedAttributes_Block23()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1942,7 +1941,7 @@ public void UnderstandsMinimizedAttributes_Block24()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1955,7 +1954,7 @@ public void UnderstandsMinimizedAttributes_Block25()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1968,7 +1967,7 @@ public void UnderstandsMinimizedAttributes_Block26()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1981,7 +1980,7 @@ public void UnderstandsMinimizedAttributes_Block27()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1994,7 +1993,7 @@ public void UnderstandsMinimizedAttributes_Block28()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2007,7 +2006,7 @@ public void UnderstandsMinimizedAttributes_Block29()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2021,7 +2020,7 @@ public void UnderstandsMinimizedAttributes_Block30()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2035,7 +2034,7 @@ public void UnderstandsMinimizedAttributes_Block31()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2049,7 +2048,7 @@ public void UnderstandsMinimizedAttributes_Block32()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2063,55 +2062,55 @@ public void UnderstandsMinimizedAttributes_Block33()
         document = $$"""@{{{document}}}""";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags1()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input unbound-required");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input unbound-required");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags2()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags3()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-int");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-int");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags4()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-int unbound-required bound-required-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-int unbound-required bound-required-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags5()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<p bound-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<p bound-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags6()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<p bound-int");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<p bound-int");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags7()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<p bound-int bound-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<p bound-int bound-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags8()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-int unbound-required bound-required-string<p bound-int bound-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-int unbound-required bound-required-string<p bound-int bound-string");
     }
 
     [Fact]
@@ -2119,7 +2118,7 @@ public void UnderstandsMinimizedBooleanBoundAttributes()
     {
         // Arrange
         var document = "<input boundbool boundbooldict-key />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -2137,7 +2136,7 @@ public void UnderstandsMinimizedBooleanBoundAttributes()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -2145,7 +2144,7 @@ public void FeatureDisabled_AddsErrorForMinimizedBooleanBoundAttributes()
     {
         // Arrange
         var document = "<input boundbool boundbooldict-key />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -2163,7 +2162,7 @@ public void FeatureDisabled_AddsErrorForMinimizedBooleanBoundAttributes()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document, languageVersion: RazorLanguageVersion.Version_2_0, fileKind: RazorFileKind.Legacy);
+        EvaluateData(tagHelpers, document, languageVersion: RazorLanguageVersion.Version_2_0, fileKind: RazorFileKind.Legacy);
     }
 
     [Fact]
@@ -2171,7 +2170,7 @@ public void Rewrites_ComponentDirectiveAttributes()
     {
         // Arrange
         var document = @"<input @bind-value=""Message"" @bind-value:event=""onchange"" />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.Create(TagHelperKind.Bind, "Bind", ComponentsApi.AssemblyName)
                 .TypeName(
@@ -2204,7 +2203,7 @@ public void Rewrites_ComponentDirectiveAttributes()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document, configureParserOptions: builder =>
+        EvaluateData(tagHelpers, document, configureParserOptions: builder =>
         {
             builder.AllowCSharpInMarkupAttributeArea = false;
         });
@@ -2215,7 +2214,7 @@ public void Rewrites_MinimizedComponentDirectiveAttributes()
     {
         // Arrange
         var document = @"<input @bind-foo @bind-foo:param />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.Create(TagHelperKind.Bind, "Bind", ComponentsApi.AssemblyName)
                 .TypeName(
@@ -2248,7 +2247,7 @@ public void Rewrites_MinimizedComponentDirectiveAttributes()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document, configureParserOptions: builder =>
+        EvaluateData(tagHelpers, document, configureParserOptions: builder =>
         {
             builder.AllowCSharpInMarkupAttributeArea = false;
         });
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperParseTreeRewriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperParseTreeRewriterTest.cs
index b93f0cadbd5..bb03a301559 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperParseTreeRewriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperParseTreeRewriterTest.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Xunit;
@@ -66,7 +65,7 @@ public void GetAttributeNameValuePairs_ParsesPairsCorrectly(
         Assert.Equal(expectedPairs, pairs);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> PartialRequiredParentTags_Descriptors =
+    public static readonly TagHelperCollection PartialRequiredParentTags_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("StrongTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
@@ -84,45 +83,45 @@ public void GetAttributeNameValuePairs_ParsesPairsCorrectly(
     public void UnderstandsPartialRequiredParentTags1()
     {
         var document = "<p><strong>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags2()
     {
         var document = "<p><strong></strong>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags3()
     {
         var document = "<p><strong></p><strong>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags4()
     {
         var document = "<<p><<strong></</strong</strong></p>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags5()
     {
         var document = "<<p><<strong></</strong></strong></p>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags6()
     {
         var document = "<<p><<custom></<</custom></custom></p>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> NestedVoidSelfClosingRequiredParent_Descriptors =
+    public static readonly TagHelperCollection NestedVoidSelfClosingRequiredParent_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -142,7 +141,7 @@ public void UnderstandsPartialRequiredParentTags6()
             .Build(),
     ];
 
-    public static ImmutableArray<TagHelperDescriptor> CatchAllAttribute_Descriptors =
+    public static readonly TagHelperCollection CatchAllAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateEventHandler("InputTagHelper1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -158,66 +157,66 @@ public void UnderstandsPartialRequiredParentTags6()
     public void UnderstandsInvalidHtml()
     {
         var document = @"<a onclick=""() => {}""><a/></a><strong>Miscolored!</strong>";
-        EvaluateData(CatchAllAttribute_Descriptors, document);
+        EvaluateData(CatchAllAttribute_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent1()
     {
         var document = "<input><strong></strong>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent2()
     {
         var document = "<p><input><strong></strong></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent3()
     {
         var document = "<p><br><strong></strong></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent4()
     {
         var document = "<p><p><br></p><strong></strong></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent5()
     {
         var document = "<input><strong></strong>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent6()
     {
         var document = "<p><input /><strong /></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent7()
     {
         var document = "<p><br /><strong /></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent8()
     {
         var document = "<p><p><br /></p><strong /></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> NestedRequiredParent_Descriptors =
+    public static readonly TagHelperCollection NestedRequiredParent_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("StrongTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -238,35 +237,35 @@ public void UnderstandsNestedVoidSelfClosingRequiredParent8()
     public void UnderstandsNestedRequiredParent1()
     {
         var document = "<strong></strong>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent2()
     {
         var document = "<p><strong></strong></p>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent3()
     {
         var document = "<div><strong></strong></div>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent4()
     {
         var document = "<strong><strong></strong></strong>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent5()
     {
         var document = "<p><strong><strong></strong></strong></p>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
@@ -274,7 +273,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildren()
     {
         // Arrange
         var documentContent = "<th:p><th:strong></th:strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -287,7 +286,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildren()
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -297,7 +296,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildrenAndRequireParent()
     {
         // Arrange
         var documentContent = "<th:p><th:strong></th:strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -310,7 +309,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildrenAndRequireParent()
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -321,7 +320,7 @@ public void InvalidStructure_UnderstandsTHPrefixAndAllowedChildrenAndRequirePare
         // Rewrite_InvalidStructure_UnderstandsTagHelperPrefixAndAllowedChildrenAndRequireParent
         // Arrange
         var documentContent = "<th:p></th:strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -334,7 +333,7 @@ public void InvalidStructure_UnderstandsTHPrefixAndAllowedChildrenAndRequirePare
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -344,7 +343,7 @@ public void NonTagHelperChild_UnderstandsTagHelperPrefixAndAllowedChildren()
     {
         // Arrange
         var documentContent = "<th:p><strong></strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -354,7 +353,7 @@ public void NonTagHelperChild_UnderstandsTagHelperPrefixAndAllowedChildren()
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -426,7 +425,7 @@ public void CanHandleInvalidChildrenWithWhitespace()
                 </strong>
             </p>
             """;
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -435,7 +434,7 @@ public void CanHandleInvalidChildrenWithWhitespace()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -443,7 +442,7 @@ public void RecoversWhenRequiredAttributeMismatchAndRestrictedChildren()
     {
         // Arrange
         var documentContent = "<strong required><strong></strong></strong>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("StrongTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -455,7 +454,7 @@ public void RecoversWhenRequiredAttributeMismatchAndRestrictedChildren()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -463,7 +462,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren_OneNull()
     {
         // Arrange
         var documentContent = "<p><strong>Hello World</strong><br></p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -485,7 +484,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren_OneNull()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -493,7 +492,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren()
     {
         // Arrange
         var documentContent = "<p><strong>Hello World</strong><br></p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -515,7 +514,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -523,10 +522,10 @@ public void UnderstandsAllowedChildren1()
     {
         // Arrange
         var documentContent = "<p><br /></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -538,10 +537,10 @@ public void UnderstandsAllowedChildren2()
             <br />
             </p>
             """;
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -549,10 +548,10 @@ public void UnderstandsAllowedChildren3()
     {
         // Arrange
         var documentContent = "<p><br></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -560,10 +559,10 @@ public void UnderstandsAllowedChildren4()
     {
         // Arrange
         var documentContent = "<p>Hello</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -571,10 +570,10 @@ public void UnderstandsAllowedChildren5()
     {
         // Arrange
         var documentContent = "<p><hr /></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["br", "strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["br", "strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -582,10 +581,10 @@ public void UnderstandsAllowedChildren6()
     {
         // Arrange
         var documentContent = "<p><br>Hello</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -593,10 +592,10 @@ public void UnderstandsAllowedChildren7()
     {
         // Arrange
         var documentContent = "<p><strong>Title:</strong><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -604,10 +603,10 @@ public void UnderstandsAllowedChildren8()
     {
         // Arrange
         var documentContent = "<p><strong>Title:</strong><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong", "br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong", "br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -615,10 +614,10 @@ public void UnderstandsAllowedChildren9()
     {
         // Arrange
         var documentContent = "<p>  <strong>Title:</strong>  <br />  Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong", "br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong", "br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -626,10 +625,10 @@ public void UnderstandsAllowedChildren10()
     {
         // Arrange
         var documentContent = "<p><strong>Title:<br><em>A Very Cool</em></strong><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -637,10 +636,10 @@ public void UnderstandsAllowedChildren11()
     {
         // Arrange
         var documentContent = "<p><custom>Title:<br><em>A Very Cool</em></custom><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -648,10 +647,10 @@ public void UnderstandsAllowedChildren12()
     {
         // Arrange
         var documentContent = "<p></</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -659,10 +658,10 @@ public void UnderstandsAllowedChildren13()
     {
         // Arrange
         var documentContent = "<p><</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -670,13 +669,13 @@ public void UnderstandsAllowedChildren14()
     {
         // Arrange
         var documentContent = "<p><custom><br>:<strong><strong>Hello</strong></strong>:<input></custom></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom", "strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom", "strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
-    private static ImmutableArray<TagHelperDescriptor> GetAllowedChildrenTagHelperDescriptors(string[] allowedChildren)
+    private static TagHelperCollection GetAllowedChildrenTagHelpers(string[] allowedChildren)
     {
         var pTagHelperBuilder = TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"));
@@ -718,13 +717,13 @@ public void AllowsSimpleHtmlCommentsAsChildren()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -742,14 +741,14 @@ public void DoesntAllowSimpleHtmlCommentsAsChildrenWhenFeatureFlagIsOff()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             document,
             languageVersion: RazorLanguageVersion.Version_2_0,
             fileKind: RazorFileKind.Legacy);
@@ -772,13 +771,13 @@ public void FailsForContentWithCommentsAsChildren()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -797,13 +796,13 @@ public void AllowsRazorCommentsAsChildren()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -825,13 +824,13 @@ public void AllowsRazorMarkupInHtmlComment()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -839,7 +838,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAll()
     {
         // Arrange
         var documentContent = "<p></</p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -851,7 +850,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAll()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -859,7 +858,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAllWithPrefix()
     {
         // Arrange
         var documentContent = "<th:p></</th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -871,7 +870,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAllWithPrefix()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent, "th:");
+        EvaluateData(tagHelpers, documentContent, "th:");
     }
 
     [Fact]
@@ -879,7 +878,7 @@ public void CanHandleStartTagOnlyTagTagMode()
     {
         // Arrange
         var documentContent = "<input>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -890,7 +889,7 @@ public void CanHandleStartTagOnlyTagTagMode()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -898,7 +897,7 @@ public void CreatesErrorForWithoutEndTagTagStructureForEndTags()
     {
         // Arrange
         var documentContent = "</input>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -909,7 +908,7 @@ public void CreatesErrorForWithoutEndTagTagStructureForEndTags()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -917,7 +916,7 @@ public void CreatesErrorForInconsistentTagStructures()
     {
         // Arrange
         var documentContent = "<input>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -934,10 +933,10 @@ public void CreatesErrorForInconsistentTagStructures()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> RequiredAttribute_Descriptors =
+    public static readonly TagHelperCollection RequiredAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -963,184 +962,184 @@ public void CreatesErrorForInconsistentTagStructures()
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly1()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly2()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p></p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p></p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly3()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly4()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div></div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div></div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly5()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly6()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"@DateTime.Now\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"@DateTime.Now\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly7()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly8()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"@DateTime.Now\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"@DateTime.Now\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly9()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\">words<strong>and</strong>spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\">words<strong>and</strong>spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly10()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"hi\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"hi\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly11()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"@DateTime.Now\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"@DateTime.Now\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly12()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"hi\">words and spaces</strong>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"hi\">words and spaces</strong>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly13()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"@DateTime.Now\">words and spaces</strong>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"@DateTime.Now\">words and spaces</strong>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly14()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly15()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div class=\"btn\"></div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div class=\"btn\"></div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly16()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p notRequired=\"a\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p notRequired=\"a\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly17()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p notRequired=\"@DateTime.Now\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p notRequired=\"@DateTime.Now\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly18()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p notRequired=\"a\" class=\"btn\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p notRequired=\"a\" class=\"btn\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly19()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly20()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"@DateTime.Now\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"@DateTime.Now\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly21()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\">words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\">words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly22()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\">words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\">words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly23()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\">words<strong>and</strong>spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\">words<strong>and</strong>spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly24()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\" catchAll=\"hi\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\" catchAll=\"hi\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly25()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\" catchAll=\"hi\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\" catchAll=\"hi\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly26()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"hi\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"hi\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly27()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly28()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"@@hi\" >words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"@@hi\" >words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly29()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\" catchAll=\"@DateTime.Now\" >words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\" catchAll=\"@DateTime.Now\" >words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly30()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words<strong>and</strong>spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words<strong>and</strong>spaces</div>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> NestedRequiredAttribute_Descriptors =
+    public static readonly TagHelperCollection NestedRequiredAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -1159,64 +1158,64 @@ public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly30()
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly1()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><p></p></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><p></p></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly2()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><strong></strong></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><strong></strong></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly3()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><strong><p></p></strong></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><strong><p></p></strong></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly4()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><p><strong></strong></p></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><p><strong></strong></p></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly5()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><strong catchAll=\"hi\"><p></p></strong></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><strong catchAll=\"hi\"><p></p></strong></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly6()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><p class=\"btn\"><strong></strong></p></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><p class=\"btn\"><strong></strong></p></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly7()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><p class=\"btn\"><p></p></p></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><p class=\"btn\"><p></p></p></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly8()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><strong catchAll=\"hi\"><strong></strong></strong></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><strong catchAll=\"hi\"><strong></strong></strong></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly9()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><p><p><p class=\"btn\"><p></p></p></p></p></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><p><p><p class=\"btn\"><p></p></p></p></p></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly10()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><strong><strong><strong catchAll=\"hi\"><strong></strong></strong></strong></strong></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><strong><strong><strong catchAll=\"hi\"><strong></strong></strong></strong></strong></strong>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> MalformedRequiredAttribute_Descriptors =
+    public static readonly TagHelperCollection MalformedRequiredAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -1229,71 +1228,71 @@ public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly10()
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly1()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly2()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\"");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\"");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly3()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\"");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\"");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly4()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p></p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p></p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly5()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\"></p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\"></p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly6()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\"></p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\"></p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly7()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\" <p>");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\" <p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly8()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\" <p>");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\" <p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly9()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\" </p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\" </p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly10()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\" </p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\" </p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly11()
     {
         var document = "<p class='foo'>@if(true){</p>}</p>";
-        EvaluateData(MalformedRequiredAttribute_Descriptors, document);
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, document);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> PrefixedTagHelperColon_Descriptors =
+    public static readonly TagHelperCollection PrefixedTagHelperColon_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("mythTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("myth"))
@@ -1308,7 +1307,7 @@ public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly1
             .Build()
     ];
 
-    public static ImmutableArray<TagHelperDescriptor> PrefixedTagHelperCatchAll_Descriptors =
+    public static readonly TagHelperCollection PrefixedTagHelperCatchAll_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("mythTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
@@ -1318,67 +1317,67 @@ public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly1
     [Fact]
     public void AllowsPrefixedTagHelpers1()
     {
-        EvaluateData(PrefixedTagHelperCatchAll_Descriptors, "<th: />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperCatchAll_TagHelpers, "<th: />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers2()
     {
-        EvaluateData(PrefixedTagHelperCatchAll_Descriptors, "<th:>words and spaces</th:>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperCatchAll_TagHelpers, "<th:>words and spaces</th:>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers3()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers4()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth></th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth></th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers5()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth><th:my2th></th:my2th></th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth><th:my2th></th:my2th></th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers6()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<!th:myth />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<!th:myth />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers7()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<!th:myth></!th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<!th:myth></!th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers8()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth class=\"btn\" />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth class=\"btn\" />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers9()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth2 class=\"btn\" />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth2 class=\"btn\" />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers10()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth class=\"btn\">words and spaces</th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth class=\"btn\">words and spaces</th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers11()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth2 bound=\"@DateTime.Now\" />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth2 bound=\"@DateTime.Now\" />", tagHelperPrefix: "th:");
     }
 
     [Fact]
@@ -1903,7 +1902,7 @@ public void HandlesNonTagHelperStartAndEndVoidTags_Correctly()
         RunParseTreeRewriterTest("<input>Foo</input>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> CaseSensitive_Descriptors =
+    public static readonly TagHelperCollection CaseSensitive_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .SetCaseSensitive()
@@ -1928,30 +1927,30 @@ public void HandlesNonTagHelperStartAndEndVoidTags_Correctly()
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly1()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<p class='foo' catchAll></p>");
+        EvaluateData(CaseSensitive_TagHelpers, "<p class='foo' catchAll></p>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly2()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<p CLASS='foo' CATCHAll></p>");
+        EvaluateData(CaseSensitive_TagHelpers, "<p CLASS='foo' CATCHAll></p>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly3()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<P class='foo' CATCHAll></P>");
+        EvaluateData(CaseSensitive_TagHelpers, "<P class='foo' CATCHAll></P>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly4()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<P class='foo'></P>");
+        EvaluateData(CaseSensitive_TagHelpers, "<P class='foo'></P>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly5()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<p Class='foo'></p>");
+        EvaluateData(CaseSensitive_TagHelpers, "<p Class='foo'></p>");
     }
 }
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperRewritingTestBase.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperRewritingTestBase.cs
index 84b85331014..06dc27ec4d4 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperRewritingTestBase.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/legacyTest/Legacy/TagHelperRewritingTestBase.cs
@@ -1,10 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using System;
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using Xunit;
 
@@ -12,39 +9,38 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy;
 
 public class TagHelperRewritingTestBase() : ParserTestBase(layer: TestProject.Layer.Compiler, validateSpanEditHandlers: true, useLegacyTokenizer: true)
 {
-    internal void RunParseTreeRewriterTest(string documentContent, params string[] tagNames)
+    internal void RunParseTreeRewriterTest(string documentContent, params ImmutableArray<string> tagNames)
     {
-        var descriptors = BuildDescriptors(tagNames);
+        var tagHelpers = BuildTagHelpers(tagNames);
 
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
-    internal ImmutableArray<TagHelperDescriptor> BuildDescriptors(params string[] tagNames)
+    internal static TagHelperCollection BuildTagHelpers(params ImmutableArray<string> tagNames)
     {
-        var descriptors = new List<TagHelperDescriptor>();
-
-        foreach (var tagName in tagNames)
+        return TagHelperCollection.Build(tagNames, (ref builder, tagNames) =>
         {
-            var descriptor = TagHelperDescriptorBuilder.CreateTagHelper(tagName + "taghelper", "SomeAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName(tagName))
-                .Build();
-            descriptors.Add(descriptor);
-        }
-
-        return descriptors.ToImmutableArray();
+            foreach (var tagName in tagNames)
+            {
+                var tagHelper = TagHelperDescriptorBuilder.CreateTagHelper(tagName + "taghelper", "SomeAssembly")
+                    .TagMatchingRuleDescriptor(rule => rule.RequireTagName(tagName))
+                    .Build();
+                builder.Add(tagHelper);
+            }
+        });
     }
 
     internal void EvaluateData(
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         string documentContent,
-        string tagHelperPrefix = null,
-        RazorLanguageVersion languageVersion = null,
+        string? tagHelperPrefix = null,
+        RazorLanguageVersion? languageVersion = null,
         RazorFileKind? fileKind = null,
-        Action<RazorParserOptions.Builder> configureParserOptions = null)
+        Action<RazorParserOptions.Builder>? configureParserOptions = null)
     {
         var syntaxTree = ParseDocument(languageVersion, documentContent, directives: default, fileKind: fileKind, configureParserOptions: configureParserOptions);
 
-        var binder = new TagHelperBinder(tagHelperPrefix, descriptors);
+        var binder = new TagHelperBinder(tagHelperPrefix, tagHelpers);
         var rewrittenTree = TagHelperParseTreeRewriter.Rewrite(syntaxTree, binder);
 
         Assert.Equal(syntaxTree.Root.Width, rewrittenTree.Root.Width);
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectEngineIntegrationTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectEngineIntegrationTest.cs
index d9952f763f7..bd32906760a 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectEngineIntegrationTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorProjectEngineIntegrationTest.cs
@@ -124,11 +124,11 @@ public void Process_WithImportsAndTagHelpers_SetsOnCodeDocument()
         var projectItem = new TestRazorProjectItem("Index.cshtml");
         var importItem = new TestRazorProjectItem("_import.cshtml");
         var expectedImports = ImmutableArray.Create(RazorSourceDocument.ReadFrom(importItem));
-        var expectedTagHelpers = new[]
-        {
+        TagHelperCollection expectedTagHelpers =
+        [
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly").Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Test2TagHelper", "TestAssembly").Build(),
-        };
+        ];
 
         var projectEngine = RazorProjectEngine.Create(RazorConfiguration.Default, TestRazorProjectFileSystem.Empty);
 
@@ -243,11 +243,11 @@ public void ProcessDesignTime_WithImportsAndTagHelpers_SetsOnCodeDocument()
         var projectItem = new TestRazorProjectItem("Index.cshtml");
         var importItem = new TestRazorProjectItem("_import.cshtml");
         var expectedImports = ImmutableArray.Create(RazorSourceDocument.ReadFrom(importItem));
-        var expectedTagHelpers = new[]
-        {
+        TagHelperCollection expectedTagHelpers =
+        [
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly").Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Test2TagHelper", "TestAssembly").Build(),
-        };
+        ];
 
         var projectEngine = RazorProjectEngine.Create(RazorConfiguration.Default, TestRazorProjectFileSystem.Empty);
 
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorTagHelperBinderPhaseTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorTagHelperBinderPhaseTest.cs
index b6cd1878a71..fc2a4bdea95 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorTagHelperBinderPhaseTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/DefaultRazorTagHelperBinderPhaseTest.cs
@@ -124,7 +124,7 @@ public void Execute_RewritesTagHelpers()
 
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelper1, tagHelper2);
+            builder.SetTagHelpers(tagHelper1, tagHelper2);
         });
 
         var source = CreateTestSourceDocument();
@@ -194,7 +194,7 @@ public void Execute_NullTagHelperDescriptorsFromCodeDocument_FallsBackToTagHelpe
 
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelper1, tagHelper2);
+            builder.SetTagHelpers(tagHelper1, tagHelper2);
         });
 
         var source = CreateTestSourceDocument();
@@ -232,7 +232,7 @@ public void Execute_EmptyTagHelperDescriptorsFromCodeDocument_DoesNotFallbackToT
 
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelper1, tagHelper2);
+            builder.SetTagHelpers(tagHelper1, tagHelper2);
         });
 
         var source = CreateTestSourceDocument();
@@ -347,7 +347,7 @@ public void Execute_TagHelpersFromCodeDocumentAndFeature_PrefersCodeDocument()
 
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(featureTagHelper);
+            builder.SetTagHelpers(featureTagHelper);
         });
 
         var source = CreateTestSourceDocument();
@@ -454,7 +454,7 @@ public void Execute_CombinesErrorsOnRewritingErrors()
 
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelper1, tagHelper2);
+            builder.SetTagHelpers(tagHelper1, tagHelper2);
         });
 
         var content =
@@ -594,7 +594,7 @@ public void DirectiveVisitor_ExtractsPrefixFromSyntaxTree(
         var parser = new RazorParser();
         var syntaxTree = parser.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.TagHelperDirectiveVisitor();
-        visitor.Initialize(descriptors: [], sourceDocument.FilePath);
+        visitor.Initialize(tagHelpers: [], sourceDocument.FilePath);
 
         // Act
         visitor.Visit(syntaxTree.Root);
@@ -603,157 +603,142 @@ public void DirectiveVisitor_ExtractsPrefixFromSyntaxTree(
         Assert.Equal(expectedPrefix, visitor.TagHelperPrefix);
     }
 
-    public static TheoryData<string, TagHelperDescriptor[], TagHelperDescriptor[]> ProcessTagHelperMatchesData
-    {
-        get
+    public static TheoryData<string, TagHelperCollection, TagHelperCollection> ProcessTagHelperMatchesData
+        // source, taghelpers, expected descriptors
+        => new()
         {
-            // source, taghelpers, expected descriptors
-            return new TheoryData<string, TagHelperDescriptor[], TagHelperDescriptor[]>
             {
-                {
-                    $@"
+                $@"
 @addTagHelper *, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, },
-                    new [] { Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyB}",
-                    new [] { Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor },
-                    new [] { Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper *, {AssemblyB}",
-                    new [] { Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor },
-                    new [] { Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyB}
 @removeTagHelper *, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor },
-                    new [] { String_TagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor],
+                [String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper {Valid_PlainTagHelperDescriptor.Name}, {AssemblyA}
 @addTagHelper *, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, },
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper {Valid_PlainTagHelperDescriptor.Name}, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, },
-                    new [] { Valid_InheritedTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor],
+                [Valid_InheritedTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, },
-                    new [] { Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor],
+                [Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, },
-                    new [] { Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor],
+                [Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper Microsoft.AspNetCore.Razor.TagHelpers.ValidPlain*, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, },
-                    new [] { Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper Microsoft.AspNetCore.Razor.TagHelpers.*, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, },
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper Microsoft.AspNetCore.Razor.TagHelpers.ValidP*, {AssemblyA}
 @addTagHelper *, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, },
-                    new [] { Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor],
+                [Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper Str*, {AssemblyB}",
-                    new [] { Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor, },
-                    new [] { Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper *, {AssemblyB}",
-                    new [] { Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor, },
-                    new [] { Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper System.{String_TagHelperDescriptor.Name}, {AssemblyB}",
-                    new [] { Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor, },
-                    new [] { Valid_PlainTagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor],
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyB}
 @removeTagHelper Microsoft.*, {AssemblyA}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor },
-                    new [] { String_TagHelperDescriptor }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor],
+                [String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyB}
 @removeTagHelper ?Microsoft*, {AssemblyA}
 @removeTagHelper System.{String_TagHelperDescriptor.Name}, {AssemblyB}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor },
-                    new []
-                    {
-                        Valid_InheritedTagHelperDescriptor,
-                        Valid_PlainTagHelperDescriptor,
-                        String_TagHelperDescriptor
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor],
+                [Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyB}
 @removeTagHelper TagHelper*, {AssemblyA}
 @removeTagHelper System.{String_TagHelperDescriptor.Name}, {AssemblyB}",
-                    new [] { Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor },
-                    new []
-                    {
-                        Valid_InheritedTagHelperDescriptor,
-                        Valid_PlainTagHelperDescriptor,
-                        String_TagHelperDescriptor
-                    }
-                },
-            };
-        }
-    }
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor],
+                [Valid_InheritedTagHelperDescriptor, Valid_PlainTagHelperDescriptor, String_TagHelperDescriptor]
+            }
+        };
 
     [Theory]
     [MemberData(nameof(ProcessTagHelperMatchesData))]
     public void DirectiveVisitor_FiltersTagHelpersByDirectives(
         string source,
-        TagHelperDescriptor[] tagHelpers,
-        TagHelperDescriptor[] expectedTagHelpers)
+        TagHelperCollection tagHelpers,
+        TagHelperCollection expectedTagHelpers)
     {
         // Arrange
         var sourceDocument = TestRazorSourceDocument.Create(source, filePath: "TestFile");
@@ -767,7 +752,7 @@ public void DirectiveVisitor_FiltersTagHelpersByDirectives(
         var results = visitor.GetResults();
 
         // Assert
-        Assert.Equal(expectedTagHelpers.Length, results.Length);
+        Assert.Equal(expectedTagHelpers.Count, results.Count);
 
         foreach (var expectedTagHelper in expectedTagHelpers)
         {
@@ -775,131 +760,88 @@ public void DirectiveVisitor_FiltersTagHelpersByDirectives(
         }
     }
 
-    public static TheoryData<string, IReadOnlyList<TagHelperDescriptor>> ProcessTagHelperMatches_EmptyResultData
-    {
-        get
+    public static TheoryData<string, TagHelperCollection> ProcessTagHelperMatches_EmptyResultData
+        // source, taghelpers
+        => new()
         {
-            // source, taghelpers
-            return new TheoryData<string, IReadOnlyList<TagHelperDescriptor>>
             {
-                {
-                    $@"
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper *, {AssemblyA}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper {Valid_PlainTagHelperDescriptor.Name}, {AssemblyA}
 @removeTagHelper {Valid_InheritedTagHelperDescriptor.Name}, {AssemblyA}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                        Valid_InheritedTagHelperDescriptor,
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyB}
 @removeTagHelper *, {AssemblyA}
 @removeTagHelper *, {AssemblyB}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                        Valid_InheritedTagHelperDescriptor,
-                        String_TagHelperDescriptor,
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @addTagHelper *, {AssemblyB}
 @removeTagHelper {Valid_PlainTagHelperDescriptor.Name}, {AssemblyA}
 @removeTagHelper {Valid_InheritedTagHelperDescriptor.Name}, {AssemblyA}
 @removeTagHelper {String_TagHelperDescriptor.Name}, {AssemblyB}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                        Valid_InheritedTagHelperDescriptor,
-                        String_TagHelperDescriptor,
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @removeTagHelper *, {AssemblyA}
 @removeTagHelper {Valid_PlainTagHelperDescriptor.Name}, {AssemblyA}",
-                    new TagHelperDescriptor[0]
-                },
-                {
-                    $@"
+                []
+            },
+            {
+                $@"
 @addTagHelper *, {AssemblyA}
 @removeTagHelper Mic*, {AssemblyA}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper Mic*, {AssemblyA}
 @removeTagHelper {Valid_PlainTagHelperDescriptor.Name}, {AssemblyA}
 @removeTagHelper {Valid_InheritedTagHelperDescriptor.Name}, {AssemblyA}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper Microsoft.*, {AssemblyA}
 @addTagHelper System.*, {AssemblyB}
 @removeTagHelper Microsoft.AspNetCore.Razor.TagHelpers*, {AssemblyA}
 @removeTagHelper System.*, {AssemblyB}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                        Valid_InheritedTagHelperDescriptor,
-                        String_TagHelperDescriptor,
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper ?icrosoft.*, {AssemblyA}
 @addTagHelper ?ystem.*, {AssemblyB}
 @removeTagHelper *?????r, {AssemblyA}
 @removeTagHelper Sy??em.*, {AssemblyB}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                        Valid_InheritedTagHelperDescriptor,
-                        String_TagHelperDescriptor,
-                    }
-                },
-                {
-                    $@"
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor]
+            },
+            {
+                $@"
 @addTagHelper ?i?crosoft.*, {AssemblyA}
 @addTagHelper ??ystem.*, {AssemblyB}",
-                    new TagHelperDescriptor[]
-                    {
-                        Valid_PlainTagHelperDescriptor,
-                        Valid_InheritedTagHelperDescriptor,
-                        String_TagHelperDescriptor,
-                    }
-                },
-            };
-        }
-    }
+                [Valid_PlainTagHelperDescriptor, Valid_InheritedTagHelperDescriptor, String_TagHelperDescriptor]
+            }
+        };
 
     [Theory]
     [MemberData(nameof(ProcessTagHelperMatches_EmptyResultData))]
     public void ProcessDirectives_CanReturnEmptyDescriptorsBasedOnDirectiveDescriptors(
         string source,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
     {
         // Arrange
         var sourceDocument = TestRazorSourceDocument.Create(source, filePath: "TestFile");
@@ -922,11 +864,11 @@ public void TagHelperDirectiveVisitor_DoesNotMatch_Components()
         // Arrange
         var componentDescriptor = CreateComponentDescriptor("counter", "SomeProject.Counter", AssemblyA);
         var legacyDescriptor = Valid_PlainTagHelperDescriptor;
-        var tagHelpers = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             legacyDescriptor,
-            componentDescriptor,
-        };
+            componentDescriptor
+        ];
 
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.TagHelperDirectiveVisitor();
         visitor.Initialize(tagHelpers, filePath: null);
@@ -975,15 +917,15 @@ public void ComponentDirectiveVisitor_DoesNotMatch_LegacyTagHelpers()
         var currentNamespace = "SomeProject";
         var componentDescriptor = CreateComponentDescriptor("counter", "SomeProject.Counter", AssemblyA);
         var legacyDescriptor = Valid_PlainTagHelperDescriptor;
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             legacyDescriptor,
-            componentDescriptor,
-        };
+            componentDescriptor
+        ];
         var sourceDocument = CreateComponentTestSourceDocument(@"<Counter />", "C:\\SomeFolder\\SomeProject\\Counter.cshtml");
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
@@ -1001,11 +943,11 @@ public void ComponentDirectiveVisitor_AddsErrorOnLegacyTagHelperDirectives()
         var currentNamespace = "SomeProject";
         var componentDescriptor = CreateComponentDescriptor("counter", "SomeProject.Counter", AssemblyA);
         var legacyDescriptor = Valid_PlainTagHelperDescriptor;
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             legacyDescriptor,
-            componentDescriptor,
-        };
+            componentDescriptor
+        ];
         var filePath = "C:\\SomeFolder\\SomeProject\\Counter.cshtml";
         var content = @"
 @tagHelperPrefix th:
@@ -1015,7 +957,7 @@ public void ComponentDirectiveVisitor_AddsErrorOnLegacyTagHelperDirectives()
         var sourceDocument = CreateComponentTestSourceDocument(content, filePath);
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
@@ -1040,17 +982,17 @@ public void ComponentDirectiveVisitor_MatchesFullyQualifiedComponents()
             "SomeProject.SomeOtherFolder.Counter",
             AssemblyA,
             fullyQualified: true);
-        var descriptors = new[]
-        {
-            componentDescriptor,
-        };
+        TagHelperCollection tagHelpers =
+        [
+            componentDescriptor
+        ];
         var filePath = "C:\\SomeFolder\\SomeProject\\Counter.cshtml";
         var content = @"
 ";
         var sourceDocument = CreateComponentTestSourceDocument(content, filePath);
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
@@ -1077,25 +1019,25 @@ public void ComponentDirectiveVisitor_ComponentInScope_MatchesChildContent()
             "SomeProject",
             "Counter",
             childContent: true);
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             componentDescriptor,
-            childContentDescriptor,
-        };
+            childContentDescriptor
+        ];
         var filePath = "C:\\SomeFolder\\SomeProject\\Counter.cshtml";
         var content = @"
 ";
         var sourceDocument = CreateComponentTestSourceDocument(content, filePath);
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
         var results = visitor.GetResults();
 
         // Assert
-        Assert.Equal(2, results.Length);
+        Assert.Equal(2, results.Count);
     }
 
     [Fact]
@@ -1112,18 +1054,18 @@ public void ComponentDirectiveVisitor_NullCurrentNamespace_MatchesOnlyFullyQuali
            "SomeProject.SomeOtherFolder.Counter",
            AssemblyA,
            fullyQualified: true);
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             componentDescriptor,
-            fullyQualifiedComponent,
-        };
+            fullyQualifiedComponent
+        ];
         var filePath = "C:\\SomeFolder\\SomeProject\\Counter.cshtml";
         var content = @"
 ";
         var sourceDocument = CreateComponentTestSourceDocument(content, filePath);
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
@@ -1147,11 +1089,11 @@ public void ComponentDirectiveVisitor_MatchesIfNamespaceInUsing()
            "Foo",
            "SomeProject.SomeOtherFolder.Foo",
            AssemblyA);
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             componentDescriptor,
-            anotherComponentDescriptor,
-        };
+            anotherComponentDescriptor
+        ];
         var filePath = "C:\\SomeFolder\\SomeProject\\Counter.cshtml";
         var content = @"
 @using SomeProject.SomeOtherFolder
@@ -1159,14 +1101,14 @@ @using SomeProject.SomeOtherFolder
         var sourceDocument = CreateComponentTestSourceDocument(content, filePath);
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
         var results = visitor.GetResults();
 
         // Assert
-        Assert.Equal(2, results.Length);
+        Assert.Equal(2, results.Count);
     }
 
     [Fact]
@@ -1178,10 +1120,10 @@ public void ComponentDirectiveVisitor_MatchesIfNamespaceInUsing_GlobalPrefix()
             "Counter",
             "SomeProject.SomeOtherFolder.Counter",
             AssemblyA);
-        var descriptors = new[]
-        {
-            componentDescriptor,
-        };
+        TagHelperCollection tagHelpers =
+        [
+            componentDescriptor
+        ];
         var filePath = "C:\\SomeFolder\\SomeProject\\Counter.cshtml";
         var content = """
             @using global::SomeProject.SomeOtherFolder
@@ -1189,7 +1131,7 @@ public void ComponentDirectiveVisitor_MatchesIfNamespaceInUsing_GlobalPrefix()
         var sourceDocument = CreateComponentTestSourceDocument(content, filePath);
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
@@ -1213,11 +1155,11 @@ public void ComponentDirectiveVisitor_DoesNotMatchForUsingAliasAndStaticUsings()
            "Foo",
            "SomeProject.SomeOtherFolder.Foo",
            AssemblyA);
-        var descriptors = new[]
-        {
-                componentDescriptor,
-                anotherComponentDescriptor,
-            };
+        TagHelperCollection tagHelpers =
+        [
+            componentDescriptor,
+            anotherComponentDescriptor
+        ];
         var filePath = "C:\\SomeFolder\\SomeProject\\Counter.cshtml";
         var content = @"
 @using Bar = SomeProject.SomeOtherFolder
@@ -1226,7 +1168,7 @@ @using static SomeProject.SomeOtherFolder.Foo
         var sourceDocument = CreateComponentTestSourceDocument(content, filePath);
         var tree = RazorSyntaxTree.Parse(sourceDocument);
         var visitor = new DefaultRazorTagHelperContextDiscoveryPhase.ComponentDirectiveVisitor();
-        visitor.Initialize(descriptors, sourceDocument.FilePath, currentNamespace);
+        visitor.Initialize(tagHelpers, sourceDocument.FilePath, currentNamespace);
 
         // Act
         visitor.Visit(tree);
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/CodeGenerationIntegrationTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/CodeGenerationIntegrationTest.cs
index c9a50288e04..849f4beaa13 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/CodeGenerationIntegrationTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/CodeGenerationIntegrationTest.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using System.Runtime.CompilerServices;
@@ -371,19 +370,19 @@ private void RunTimeTest(string testName)
         AssertCSharpDiagnosticsMatchBaseline(codeDocument, testName);
     }
 
-    private void RunTagHelpersTest(IEnumerable<TagHelperDescriptor> descriptors, [CallerMemberName] string testName = "")
+    private void RunTagHelpersTest(TagHelperCollection tagHelpers, [CallerMemberName] string testName = "")
     {
         if (designTime)
         {
-            RunDesignTimeTagHelpersTest(descriptors, testName);
+            RunDesignTimeTagHelpersTest(tagHelpers, testName);
         }
         else
         {
-            RunRuntimeTagHelpersTest(descriptors, testName);
+            RunRuntimeTagHelpersTest(tagHelpers, testName);
         }
     }
 
-    private void RunRuntimeTagHelpersTest(IEnumerable<TagHelperDescriptor> descriptors, string testName)
+    private void RunRuntimeTagHelpersTest(TagHelperCollection tagHelpers, string testName)
     {
         // Arrange
         var projectEngine = CreateProjectEngine(RazorExtensions.Register);
@@ -391,10 +390,10 @@ private void RunRuntimeTagHelpersTest(IEnumerable<TagHelperDescriptor> descripto
         var projectItem = CreateProjectItemFromFile(testName: testName);
         var imports = GetImports(projectEngine, projectItem);
 
-        AddTagHelperStubs(descriptors);
+        AddTagHelperStubs(tagHelpers);
 
         // Act
-        var codeDocument = projectEngine.Process(RazorSourceDocument.ReadFrom(projectItem), RazorFileKind.Legacy, imports, descriptors.ToList());
+        var codeDocument = projectEngine.Process(RazorSourceDocument.ReadFrom(projectItem), RazorFileKind.Legacy, imports, tagHelpers);
 
         // Assert
         AssertDocumentNodeMatchesBaseline(codeDocument.GetRequiredDocumentNode(), testName);
@@ -402,7 +401,7 @@ private void RunRuntimeTagHelpersTest(IEnumerable<TagHelperDescriptor> descripto
         AssertCSharpDiagnosticsMatchBaseline(codeDocument, testName);
     }
 
-    private void RunDesignTimeTagHelpersTest(IEnumerable<TagHelperDescriptor> descriptors, string testName)
+    private void RunDesignTimeTagHelpersTest(TagHelperCollection tagHelpers, string testName)
     {
         // Arrange
         var projectEngine = CreateProjectEngine(RazorExtensions.Register);
@@ -410,10 +409,10 @@ private void RunDesignTimeTagHelpersTest(IEnumerable<TagHelperDescriptor> descri
         var projectItem = CreateProjectItemFromFile(testName: testName);
         var imports = GetImports(projectEngine, projectItem);
 
-        AddTagHelperStubs(descriptors);
+        AddTagHelperStubs(tagHelpers);
 
         // Act
-        var codeDocument = projectEngine.ProcessDesignTime(RazorSourceDocument.ReadFrom(projectItem), RazorFileKind.Legacy, imports, descriptors.ToList());
+        var codeDocument = projectEngine.ProcessDesignTime(RazorSourceDocument.ReadFrom(projectItem), RazorFileKind.Legacy, imports, tagHelpers);
 
         // Assert
         AssertDocumentNodeMatchesBaseline(codeDocument.GetRequiredDocumentNode(), testName);
@@ -435,9 +434,9 @@ private static ImmutableArray<RazorSourceDocument> GetImports(RazorProjectEngine
         return result.ToImmutable();
     }
 
-    private void AddTagHelperStubs(IEnumerable<TagHelperDescriptor> descriptors)
+    private void AddTagHelperStubs(TagHelperCollection tagHelpers)
     {
-        var tagHelperClasses = descriptors.Select(descriptor =>
+        var tagHelperClasses = tagHelpers.Select(descriptor =>
         {
             var typeName = descriptor.TypeName;
             var namespaceSeparatorIndex = typeName.LastIndexOf('.');
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TagHelpersIntegrationTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TagHelpersIntegrationTest.cs
index 7aae3295dbc..37440b08e53 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TagHelpersIntegrationTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TagHelpersIntegrationTest.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using Xunit;
+using static Microsoft.AspNetCore.Mvc.Razor.Extensions.ViewComponentsApi;
 
 namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests;
 
@@ -13,15 +14,15 @@ public class TagHelpersIntegrationTest() : IntegrationTestBase(layer: TestProjec
     public void SimpleTagHelpers()
     {
         // Arrange
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             CreateTagHelperDescriptor(
                 tagName: "input",
                 typeName: "InputTagHelper",
                 assemblyName: "TestAssembly")
-        };
+        ];
 
-        var projectEngine = CreateProjectEngine(builder => builder.AddTagHelpers(descriptors));
+        var projectEngine = CreateProjectEngine(builder => builder.SetTagHelpers(tagHelpers));
         var projectItem = CreateProjectItemFromFile();
 
         // Act
@@ -35,22 +36,22 @@ public void SimpleTagHelpers()
     public void TagHelpersWithBoundAttributes()
     {
         // Arrange
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             CreateTagHelperDescriptor(
                 tagName: "input",
                 typeName: "InputTagHelper",
                 assemblyName: "TestAssembly",
-                attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                {
+                attributes:
+                [
                     builder => builder
                         .Name("bound")
                         .PropertyName("FooProp")
                         .TypeName("System.String"),
-                })
-        };
+                ])
+        ];
 
-        var projectEngine = CreateProjectEngine(builder => builder.AddTagHelpers(descriptors));
+        var projectEngine = CreateProjectEngine(builder => builder.SetTagHelpers(tagHelpers));
         var projectItem = CreateProjectItemFromFile();
 
         // Act
@@ -64,8 +65,8 @@ public void TagHelpersWithBoundAttributes()
     public void NestedTagHelpers()
     {
         // Arrange
-        var descriptors = new[]
-        {
+        TagHelperCollection tagHelpers =
+        [
             CreateTagHelperDescriptor(
                 tagName: "p",
                 typeName: "PTagHelper",
@@ -78,16 +79,16 @@ public void NestedTagHelpers()
                 tagName: "input",
                 typeName: "InputTagHelper",
                 assemblyName: "TestAssembly",
-                attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                {
+                attributes:
+                [
                     builder => builder
                         .Name("value")
                         .PropertyName("FooProp")
                         .TypeName("System.String"),
-                })
-        };
+                ])
+        ];
 
-        var projectEngine = CreateProjectEngine(builder => builder.AddTagHelpers(descriptors));
+        var projectEngine = CreateProjectEngine(builder => builder.SetTagHelpers(tagHelpers));
         var projectItem = CreateProjectItemFromFile();
 
         // Act
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TestTagHelperDescriptors.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TestTagHelperDescriptors.cs
index eaa229621bb..85d9d549423 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TestTagHelperDescriptors.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/TestTagHelperDescriptors.cs
@@ -1,460 +1,461 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Reflection;
+using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Language.IntegrationTests;
 
 public class TestTagHelperDescriptors
 {
-    public static IEnumerable<TagHelperDescriptor> SimpleTagHelperDescriptors
+    public static TagHelperCollection SimpleTagHelperDescriptors
     {
         get
         {
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "span",
-                        typeName: "SpanTagHelper",
-                        assemblyName: "TestAssembly"),
-                    CreateTagHelperDescriptor(
-                        tagName: "div",
-                        typeName: "DivTagHelper",
-                        assemblyName: "TestAssembly"),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "InputTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .Name("value")
-                                .PropertyName("FooProp")
-                                .TypeName("System.String"),
-                            builder => builder
-                                .Name("bound")
-                                .PropertyName("BoundProp")
-                                .TypeName("System.String"),
-                            builder => builder
-                                .Name("age")
-                                .PropertyName("AgeProp")
-                                .TypeName("System.Int32"),
-                            builder => builder
-                                .Name("alive")
-                                .PropertyName("AliveProp")
-                                .TypeName("System.Boolean"),
-                            builder => builder
-                                .Name("tag")
-                                .PropertyName("TagProp")
-                                .TypeName("System.Object"),
-                            builder => builder
-                                .Name("tuple-dictionary")
-                                .PropertyName("DictionaryOfBoolAndStringTupleProperty")
-                                .TypeName(typeof(IDictionary<string, int>).Namespace + ".IDictionary<System.String, (System.Boolean, System.String)>")
-                                .AsDictionaryAttribute("tuple-prefix-", typeof((bool, string)).FullName)
-                        })
-                };
+            return
+                [
+                CreateTagHelperDescriptor(
+                    tagName: "span",
+                    typeName: "SpanTagHelper",
+                    assemblyName: "TestAssembly"),
+                CreateTagHelperDescriptor(
+                    tagName: "div",
+                    typeName: "DivTagHelper",
+                    assemblyName: "TestAssembly"),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "InputTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => builder
+                            .Name("value")
+                            .PropertyName("FooProp")
+                            .TypeName("System.String"),
+                        builder => builder
+                            .Name("bound")
+                            .PropertyName("BoundProp")
+                            .TypeName("System.String"),
+                        builder => builder
+                            .Name("age")
+                            .PropertyName("AgeProp")
+                            .TypeName("System.Int32"),
+                        builder => builder
+                            .Name("alive")
+                            .PropertyName("AliveProp")
+                            .TypeName("System.Boolean"),
+                        builder => builder
+                            .Name("tag")
+                            .PropertyName("TagProp")
+                            .TypeName("System.Object"),
+                        builder => builder
+                            .Name("tuple-dictionary")
+                            .PropertyName("DictionaryOfBoolAndStringTupleProperty")
+                            .TypeName(typeof(IDictionary<string, int>).Namespace + ".IDictionary<System.String, (System.Boolean, System.String)>")
+                            .AsDictionaryAttribute("tuple-prefix-", typeof((bool, string)).FullName)
+                    ])
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> MinimizedBooleanTagHelperDescriptors
+    public static TagHelperCollection MinimizedBooleanTagHelperDescriptors
     {
         get
         {
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "span",
-                        typeName: "SpanTagHelper",
-                        assemblyName: "TestAssembly"),
-                    CreateTagHelperDescriptor(
-                        tagName: "div",
-                        typeName: "DivTagHelper",
-                        assemblyName: "TestAssembly"),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "InputTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .Name("value")
-                                .PropertyName("FooProp")
-                                .TypeName("System.String"),
-                            builder => builder
-                                .Name("bound")
-                                .PropertyName("BoundProp")
-                                .TypeName("System.Boolean"),
-                            builder => builder
-                                .Name("age")
-                                .PropertyName("AgeProp")
-                                .TypeName("System.Int32"),
-                        })
-                };
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "span",
+                    typeName: "SpanTagHelper",
+                    assemblyName: "TestAssembly"),
+                CreateTagHelperDescriptor(
+                    tagName: "div",
+                    typeName: "DivTagHelper",
+                    assemblyName: "TestAssembly"),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "InputTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => builder
+                            .Name("value")
+                            .PropertyName("FooProp")
+                            .TypeName("System.String"),
+                        builder => builder
+                            .Name("bound")
+                            .PropertyName("BoundProp")
+                            .TypeName("System.Boolean"),
+                        builder => builder
+                            .Name("age")
+                            .PropertyName("AgeProp")
+                            .TypeName("System.Int32"),
+                    ])
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> CssSelectorTagHelperDescriptors
+    public static TagHelperCollection CssSelectorTagHelperDescriptors
     {
         get
         {
-            var inputTypePropertyInfo = typeof(TestType).GetRuntimeProperty("Type");
-            var inputCheckedPropertyInfo = typeof(TestType).GetRuntimeProperty("Checked");
+            var inputTypePropertyInfo = GetTestTypeRuntimeProperty("Type");
+            var inputCheckedPropertyInfo = GetTestTypeRuntimeProperty("Checked");
 
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "a",
-                        typeName: "TestNamespace.ATagHelper",
-                        assemblyName: "TestAssembly",
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute
-                                    .Name("href", RequiredAttributeNameComparison.FullMatch)
-                                    .Value("~/", RequiredAttributeValueComparison.FullMatch)),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "a",
-                        typeName: "TestNamespace.ATagHelperMultipleSelectors",
-                        assemblyName: "TestAssembly",
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute
-                                    .Name("href", RequiredAttributeNameComparison.FullMatch)
-                                    .Value("~/", RequiredAttributeValueComparison.PrefixMatch))
-                                .RequireAttributeDescriptor(attribute => attribute
-                                    .Name("href", RequiredAttributeNameComparison.FullMatch)
-                                    .Value("?hello=world", RequiredAttributeValueComparison.SuffixMatch)),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute
-                                    .Name("type", RequiredAttributeNameComparison.FullMatch)
-                                    .Value("text", RequiredAttributeValueComparison.FullMatch)),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper2",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute
-                                    .Name("ty", RequiredAttributeNameComparison.PrefixMatch)),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "*",
-                        typeName: "TestNamespace.CatchAllTagHelper",
-                        assemblyName: "TestAssembly",
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute
-                                    .Name("href", RequiredAttributeNameComparison.FullMatch)
-                                    .Value("~/", RequiredAttributeValueComparison.PrefixMatch)),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "*",
-                        typeName: "TestNamespace.CatchAllTagHelper2",
-                        assemblyName: "TestAssembly",
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute
-                                    .Name("type", RequiredAttributeNameComparison.FullMatch)),
-                        }),
-                };
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "a",
+                    typeName: "TestNamespace.ATagHelper",
+                    assemblyName: "TestAssembly",
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute
+                                .Name("href", RequiredAttributeNameComparison.FullMatch)
+                                .Value("~/", RequiredAttributeValueComparison.FullMatch)),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "a",
+                    typeName: "TestNamespace.ATagHelperMultipleSelectors",
+                    assemblyName: "TestAssembly",
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute
+                                .Name("href", RequiredAttributeNameComparison.FullMatch)
+                                .Value("~/", RequiredAttributeValueComparison.PrefixMatch))
+                            .RequireAttributeDescriptor(attribute => attribute
+                                .Name("href", RequiredAttributeNameComparison.FullMatch)
+                                .Value("?hello=world", RequiredAttributeValueComparison.SuffixMatch)),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute
+                                .Name("type", RequiredAttributeNameComparison.FullMatch)
+                                .Value("text", RequiredAttributeValueComparison.FullMatch)),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper2",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute
+                                .Name("ty", RequiredAttributeNameComparison.PrefixMatch)),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "*",
+                    typeName: "TestNamespace.CatchAllTagHelper",
+                    assemblyName: "TestAssembly",
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute
+                                .Name("href", RequiredAttributeNameComparison.FullMatch)
+                                .Value("~/", RequiredAttributeValueComparison.PrefixMatch)),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "*",
+                    typeName: "TestNamespace.CatchAllTagHelper2",
+                    assemblyName: "TestAssembly",
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute
+                                .Name("type", RequiredAttributeNameComparison.FullMatch)),
+                    ]),
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> EnumTagHelperDescriptors
+    public static TagHelperCollection EnumTagHelperDescriptors
     {
         get
         {
-            return new[]
-            {
+            return
+            [
                 CreateTagHelperDescriptor(
                     tagName: "*",
                     typeName: "TestNamespace.CatchAllTagHelper",
                     assemblyName: "TestAssembly",
-                    attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                    {
+                    attributes:
+                    [
                         builder => builder
                             .Name("catch-all")
                             .PropertyName("CatchAll")
                             .AsEnum()
                             .TypeName("Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestTagHelperDescriptors.MyEnum"),
-                    }),
+                    ]),
                 CreateTagHelperDescriptor(
                     tagName: "input",
                     typeName: "TestNamespace.InputTagHelper",
                     assemblyName: "TestAssembly",
-                    attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                    {
+                    attributes:
+                    [
                         builder => builder
                             .Name("value")
                             .PropertyName("Value")
                             .AsEnum()
                             .TypeName("Microsoft.AspNetCore.Razor.Language.IntegrationTests.TestTagHelperDescriptors.MyEnum"),
-                    }),
-            };
+                    ]),
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> SymbolBoundTagHelperDescriptors
+    public static TagHelperCollection SymbolBoundTagHelperDescriptors
     {
         get
         {
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "*",
-                        typeName: "TestNamespace.CatchAllTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .Name("[item]")
-                                .PropertyName("ListItems")
-                                .TypeName("System.Collections.Generic.List<string>"),
-                            builder => builder
-                                .Name("[(item)]")
-                                .PropertyName("ArrayItems")
-                                .TypeName(typeof(string[]).FullName),
-                            builder => builder
-                                .Name("(click)")
-                                .PropertyName("Event1")
-                                .TypeName(typeof(Action).FullName),
-                            builder => builder
-                                .Name("(^click)")
-                                .PropertyName("Event2")
-                                .TypeName(typeof(Action).FullName),
-                            builder => builder
-                                .Name("*something")
-                                .PropertyName("StringProperty1")
-                                .TypeName(typeof(string).FullName),
-                            builder => builder
-                                .Name("#local")
-                                .PropertyName("StringProperty2")
-                                .TypeName(typeof(string).FullName),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("bound")),
-                        }),
-                };
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "*",
+                    typeName: "TestNamespace.CatchAllTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => builder
+                            .Name("[item]")
+                            .PropertyName("ListItems")
+                            .TypeName("System.Collections.Generic.List<string>"),
+                        builder => builder
+                            .Name("[(item)]")
+                            .PropertyName("ArrayItems")
+                            .TypeName(typeof(string[]).FullName),
+                        builder => builder
+                            .Name("(click)")
+                            .PropertyName("Event1")
+                            .TypeName(typeof(Action).FullName),
+                        builder => builder
+                            .Name("(^click)")
+                            .PropertyName("Event2")
+                            .TypeName(typeof(Action).FullName),
+                        builder => builder
+                            .Name("*something")
+                            .PropertyName("StringProperty1")
+                            .TypeName(typeof(string).FullName),
+                        builder => builder
+                            .Name("#local")
+                            .PropertyName("StringProperty2")
+                            .TypeName(typeof(string).FullName),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("bound")),
+                    ]),
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> MinimizedTagHelpers_Descriptors
+    public static TagHelperCollection MinimizedTagHelpers_Descriptors
     {
         get
         {
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "*",
-                        typeName: "TestNamespace.CatchAllTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .Name("catchall-bound-string")
-                                .PropertyName("BoundRequiredString")
-                                .TypeName(typeof(string).FullName),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("catchall-unbound-required")),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .Name("input-bound-required-string")
-                                .PropertyName("BoundRequiredString")
-                                .TypeName(typeof(string).FullName),
-                            builder => builder
-                                .Name("input-bound-string")
-                                .PropertyName("BoundString")
-                                .TypeName(typeof(string).FullName),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute.Name("input-bound-required-string"))
-                                .RequireAttributeDescriptor(attribute => attribute.Name("input-unbound-required")),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "div",
-                        typeName: "DivTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .Name("boundbool")
-                                .PropertyName("BoundBoolProp")
-                                .TypeName(typeof(bool).FullName),
-                            builder => builder
-                                .Name("booldict")
-                                .PropertyName("BoolDictProp")
-                                .TypeName("System.Collections.Generic.IDictionary<string, bool>")
-                                .AsDictionaryAttribute("booldict-prefix-", typeof(bool).FullName),
-                        }),
-                };
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "*",
+                    typeName: "TestNamespace.CatchAllTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => builder
+                            .Name("catchall-bound-string")
+                            .PropertyName("BoundRequiredString")
+                            .TypeName(typeof(string).FullName),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("catchall-unbound-required")),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => builder
+                            .Name("input-bound-required-string")
+                            .PropertyName("BoundRequiredString")
+                            .TypeName(typeof(string).FullName),
+                        builder => builder
+                            .Name("input-bound-string")
+                            .PropertyName("BoundString")
+                            .TypeName(typeof(string).FullName),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute.Name("input-bound-required-string"))
+                            .RequireAttributeDescriptor(attribute => attribute.Name("input-unbound-required")),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "div",
+                    typeName: "DivTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => builder
+                            .Name("boundbool")
+                            .PropertyName("BoundBoolProp")
+                            .TypeName(typeof(bool).FullName),
+                        builder => builder
+                            .Name("booldict")
+                            .PropertyName("BoolDictProp")
+                            .TypeName("System.Collections.Generic.IDictionary<string, bool>")
+                            .AsDictionaryAttribute("booldict-prefix-", typeof(bool).FullName),
+                    ]),
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> DynamicAttributeTagHelpers_Descriptors
+    public static TagHelperCollection DynamicAttributeTagHelpers_Descriptors
     {
         get
         {
-            return new[]
-            {
+            return
+            [
                 CreateTagHelperDescriptor(
                     tagName: "input",
                     typeName: "TestNamespace.InputTagHelper",
                     assemblyName: "TestAssembly",
-                    attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                    {
+                    attributes:
+                    [
                         builder => builder
                             .Name("bound")
                             .PropertyName("Bound")
                             .TypeName(typeof(string).FullName)
-                    }),
-                };
+                    ]),
+                ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> DuplicateTargetTagHelperDescriptors
+    public static TagHelperCollection DuplicateTargetTagHelperDescriptors
     {
         get
         {
-            var typePropertyInfo = typeof(TestType).GetRuntimeProperty("Type");
-            var checkedPropertyInfo = typeof(TestType).GetRuntimeProperty("Checked");
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "*",
-                        typeName: "TestNamespace.CatchAllTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", typePropertyInfo),
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", checkedPropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("type")),
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("checked"))
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", typePropertyInfo),
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", checkedPropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("type")),
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("checked"))
-                        })
-                };
+            var typePropertyInfo = GetTestTypeRuntimeProperty("Type");
+            var checkedPropertyInfo = GetTestTypeRuntimeProperty("Checked");
+
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "*",
+                    typeName: "TestNamespace.CatchAllTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", typePropertyInfo),
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", checkedPropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("type")),
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("checked"))
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", typePropertyInfo),
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", checkedPropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("type")),
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("checked"))
+                    ])
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> AttributeTargetingTagHelperDescriptors
+    public static TagHelperCollection AttributeTargetingTagHelperDescriptors
     {
         get
         {
-            var inputTypePropertyInfo = typeof(TestType).GetRuntimeProperty("Type");
-            var inputCheckedPropertyInfo = typeof(TestType).GetRuntimeProperty("Checked");
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "p",
-                        typeName: "TestNamespace.PTagHelper",
-                        assemblyName: "TestAssembly",
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("class")),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("type")),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper2",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", inputCheckedPropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder
-                                .RequireAttributeDescriptor(attribute => attribute.Name("type"))
-                                .RequireAttributeDescriptor(attribute => attribute.Name("checked")),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "*",
-                        typeName: "TestNamespace.CatchAllTagHelper",
-                        assemblyName: "TestAssembly",
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("catchAll")),
-                        }),
-                };
+            var inputTypePropertyInfo = GetTestTypeRuntimeProperty("Type");
+            var inputCheckedPropertyInfo = GetTestTypeRuntimeProperty("Checked");
+
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "p",
+                    typeName: "TestNamespace.PTagHelper",
+                    assemblyName: "TestAssembly",
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("class")),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("type")),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper2",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", inputCheckedPropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder
+                            .RequireAttributeDescriptor(attribute => attribute.Name("type"))
+                            .RequireAttributeDescriptor(attribute => attribute.Name("checked")),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "*",
+                    typeName: "TestNamespace.CatchAllTagHelper",
+                    assemblyName: "TestAssembly",
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireAttributeDescriptor(attribute => attribute.Name("catchAll")),
+                    ]),
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> PrefixedAttributeTagHelperDescriptors
+    public static TagHelperCollection PrefixedAttributeTagHelperDescriptors
     {
         get
         {
-            return new[]
-            {
+            return
+            [
                 CreateTagHelperDescriptor(
                     tagName: "input",
                     typeName: "TestNamespace.InputTagHelper1",
                     assemblyName: "TestAssembly",
-                    attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                    {
+                    attributes:
+                    [
                         builder => builder
                             .Name("int-prefix-grabber")
                             .PropertyName("IntProperty")
@@ -473,13 +474,13 @@ public static IEnumerable<TagHelperDescriptor> PrefixedAttributeTagHelperDescrip
                             .PropertyName("StringDictionaryProperty")
                             .TypeName("Namespace.DictionaryWithoutParameterlessConstructor<string, string>")
                             .AsDictionaryAttribute("string-prefix-", typeof(string).FullName),
-                    }),
+                    ]),
                 CreateTagHelperDescriptor(
                     tagName: "input",
                     typeName: "TestNamespace.InputTagHelper2",
                     assemblyName: "TestAssembly",
-                    attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                    {
+                    attributes:
+                    [
                         builder => builder
                             .Name("int-dictionary")
                             .PropertyName("IntDictionaryProperty")
@@ -490,78 +491,79 @@ public static IEnumerable<TagHelperDescriptor> PrefixedAttributeTagHelperDescrip
                             .PropertyName("StringDictionaryProperty")
                             .TypeName("Namespace.DictionaryWithoutParameterlessConstructor<string, string>")
                             .AsDictionaryAttribute("string-prefix-", typeof(string).FullName),
-                    }),
-            };
+                    ]),
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> TagHelpersInSectionDescriptors
+    public static TagHelperCollection TagHelpersInSectionDescriptors
     {
         get
         {
-            var propertyInfo = typeof(TestType).GetRuntimeProperty("BoundProperty");
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "MyTagHelper",
-                        typeName: "TestNamespace.MyTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "BoundProperty", propertyInfo),
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "NestedTagHelper",
-                        typeName: "TestNamespace.NestedTagHelper",
-                        assemblyName: "TestAssembly"),
-                };
+            var propertyInfo = GetTestTypeRuntimeProperty("BoundProperty");
+
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "MyTagHelper",
+                    typeName: "TestNamespace.MyTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "BoundProperty", propertyInfo),
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "NestedTagHelper",
+                    typeName: "TestNamespace.NestedTagHelper",
+                    assemblyName: "TestAssembly"),
+            ];
         }
     }
 
-    public static IEnumerable<TagHelperDescriptor> DefaultPAndInputTagHelperDescriptors
+    public static TagHelperCollection DefaultPAndInputTagHelperDescriptors
     {
         get
         {
-            var pAgePropertyInfo = typeof(TestType).GetRuntimeProperty("Age");
-            var inputTypePropertyInfo = typeof(TestType).GetRuntimeProperty("Type");
-            var checkedPropertyInfo = typeof(TestType).GetRuntimeProperty("Checked");
+            var pAgePropertyInfo = GetTestTypeRuntimeProperty("Age");
+            var inputTypePropertyInfo = GetTestTypeRuntimeProperty("Type");
+            var checkedPropertyInfo = GetTestTypeRuntimeProperty("Checked");
 
-            return new[]
-            {
-                    CreateTagHelperDescriptor(
-                        tagName: "p",
-                        typeName: "TestNamespace.PTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "age", pAgePropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireTagStructure(TagStructure.NormalOrSelfClosing)
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
-                        },
-                        ruleBuilders: new Action<TagMatchingRuleDescriptorBuilder>[]
-                        {
-                            builder => builder.RequireTagStructure(TagStructure.WithoutEndTag)
-                        }),
-                    CreateTagHelperDescriptor(
-                        tagName: "input",
-                        typeName: "TestNamespace.InputTagHelper2",
-                        assemblyName: "TestAssembly",
-                        attributes: new Action<BoundAttributeDescriptorBuilder>[]
-                        {
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
-                            builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", checkedPropertyInfo),
-                        }),
-                };
+            return
+            [
+                CreateTagHelperDescriptor(
+                    tagName: "p",
+                    typeName: "TestNamespace.PTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "age", pAgePropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireTagStructure(TagStructure.NormalOrSelfClosing)
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
+                    ],
+                    ruleBuilders:
+                    [
+                        builder => builder.RequireTagStructure(TagStructure.WithoutEndTag)
+                    ]),
+                CreateTagHelperDescriptor(
+                    tagName: "input",
+                    typeName: "TestNamespace.InputTagHelper2",
+                    assemblyName: "TestAssembly",
+                    attributes:
+                    [
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "type", inputTypePropertyInfo),
+                        builder => BuildBoundAttributeDescriptorFromPropertyInfo(builder, "checked", checkedPropertyInfo),
+                    ]),
+            ];
         }
     }
 
@@ -569,8 +571,8 @@ private static TagHelperDescriptor CreateTagHelperDescriptor(
         string tagName,
         string typeName,
         string assemblyName,
-        IEnumerable<Action<BoundAttributeDescriptorBuilder>> attributes = null,
-        IEnumerable<Action<TagMatchingRuleDescriptorBuilder>> ruleBuilders = null)
+        IEnumerable<Action<BoundAttributeDescriptorBuilder>>? attributes = null,
+        IEnumerable<Action<TagMatchingRuleDescriptorBuilder>>? ruleBuilders = null)
     {
         var builder = TagHelperDescriptorBuilder.CreateTagHelper(typeName, assemblyName);
         builder.SetTypeName(typeName, typeNamespace: null, typeNameIdentifier: null);
@@ -604,6 +606,14 @@ private static TagHelperDescriptor CreateTagHelperDescriptor(
         return descriptor;
     }
 
+    private static PropertyInfo GetTestTypeRuntimeProperty(string name)
+    {
+        var result = typeof(TestType).GetRuntimeProperty(name);
+        Assert.NotNull(result);
+
+        return result;
+    }
+
     private static void BuildBoundAttributeDescriptorFromPropertyInfo(
         BoundAttributeDescriptorBuilder builder,
         string name,
@@ -624,11 +634,11 @@ private class TestType
     {
         public int Age { get; set; }
 
-        public string Type { get; set; }
+        public string? Type { get; set; }
 
         public bool Checked { get; set; }
 
-        public string BoundProperty { get; set; }
+        public string? BoundProperty { get; set; }
     }
 
     public static readonly string Code = """
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperBlockRewriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperBlockRewriterTest.cs
index 3bbcb7584ee..b1c2d8b7d0f 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperBlockRewriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperBlockRewriterTest.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Globalization;
 using Microsoft.AspNetCore.Razor.Language.Components;
 using Roslyn.Test.Utilities;
@@ -13,7 +12,7 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy;
 
 public class TagHelperBlockRewriterTest : TagHelperRewritingTestBase
 {
-    public static ImmutableArray<TagHelperDescriptor> SymbolBoundAttributes_Descriptors =
+    public static readonly TagHelperCollection SymbolBoundAttributes_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("CatchAllTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -49,46 +48,46 @@ public class TagHelperBlockRewriterTest : TagHelperRewritingTestBase
     [Fact]
     public void CanHandleSymbolBoundAttributes1()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<ul bound [item]='items'></ul>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<ul bound [item]='items'></ul>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes2()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<ul bound [(item)]='items'></ul>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<ul bound [(item)]='items'></ul>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes3()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<button bound (click)='doSomething()'>Click Me</button>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<button bound (click)='doSomething()'>Click Me</button>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes4()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<button bound (^click)='doSomething()'>Click Me</button>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<button bound (^click)='doSomething()'>Click Me</button>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes5()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<template bound *something='value'></template>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<template bound *something='value'></template>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes6()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<div bound #localminimized></div>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<div bound #localminimized></div>");
     }
 
     [Fact]
     public void CanHandleSymbolBoundAttributes7()
     {
-        EvaluateData(SymbolBoundAttributes_Descriptors, "<div bound #local='value'></div>");
+        EvaluateData(SymbolBoundAttributes_TagHelpers, "<div bound #local='value'></div>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> WithoutEndTag_Descriptors =
+    public static readonly TagHelperCollection WithoutEndTag_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -100,34 +99,34 @@ public void CanHandleSymbolBoundAttributes7()
     [Fact]
     public void CanHandleWithoutEndTagTagStructure1()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure2()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input type='text'>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input type='text'>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure3()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input><input>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input><input>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure4()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<input type='text'><input>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<input type='text'><input>");
     }
 
     [Fact]
     public void CanHandleWithoutEndTagTagStructure5()
     {
-        EvaluateData(WithoutEndTag_Descriptors, "<div><input><input></div>");
+        EvaluateData(WithoutEndTag_TagHelpers, "<div><input><input></div>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> GetTagStructureCompatibilityDescriptors(TagStructure structure1, TagStructure structure2)
+    public static TagHelperCollection GetTagStructureCompatibilityTagHelpers(TagStructure structure1, TagStructure structure2)
     {
         return
         [
@@ -148,7 +147,7 @@ public static ImmutableArray<TagHelperDescriptor> GetTagStructureCompatibilityDe
     public void AllowsCompatibleTagStructures1()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.Unspecified);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.Unspecified);
 
         // Act & Assert
         EvaluateData(descriptors, "<input></input>");
@@ -158,7 +157,7 @@ public void AllowsCompatibleTagStructures1()
     public void AllowsCompatibleTagStructures2()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.Unspecified);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.Unspecified);
 
         // Act & Assert
         EvaluateData(descriptors, "<input />");
@@ -168,7 +167,7 @@ public void AllowsCompatibleTagStructures2()
     public void AllowsCompatibleTagStructures3()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.WithoutEndTag);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.WithoutEndTag);
 
         // Act & Assert
         EvaluateData(descriptors, "<input type='text'>");
@@ -178,7 +177,7 @@ public void AllowsCompatibleTagStructures3()
     public void AllowsCompatibleTagStructures4()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.WithoutEndTag, TagStructure.WithoutEndTag);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.WithoutEndTag, TagStructure.WithoutEndTag);
 
         // Act & Assert
         EvaluateData(descriptors, "<input><input>");
@@ -188,7 +187,7 @@ public void AllowsCompatibleTagStructures4()
     public void AllowsCompatibleTagStructures5()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.NormalOrSelfClosing);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.NormalOrSelfClosing);
 
         // Act & Assert
         EvaluateData(descriptors, "<input type='text'></input>");
@@ -198,7 +197,7 @@ public void AllowsCompatibleTagStructures5()
     public void AllowsCompatibleTagStructures6()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.Unspecified, TagStructure.WithoutEndTag);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.Unspecified, TagStructure.WithoutEndTag);
 
         // Act & Assert
         EvaluateData(descriptors, "<input />");
@@ -208,7 +207,7 @@ public void AllowsCompatibleTagStructures6()
     public void AllowsCompatibleTagStructures7()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.NormalOrSelfClosing, TagStructure.Unspecified);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.NormalOrSelfClosing, TagStructure.Unspecified);
 
         // Act & Assert
         EvaluateData(descriptors, "<input />");
@@ -218,7 +217,7 @@ public void AllowsCompatibleTagStructures7()
     public void AllowsCompatibleTagStructures8()
     {
         // Arrange
-        var descriptors = GetTagStructureCompatibilityDescriptors(TagStructure.WithoutEndTag, TagStructure.Unspecified);
+        var descriptors = GetTagStructureCompatibilityTagHelpers(TagStructure.WithoutEndTag, TagStructure.Unspecified);
 
         // Act & Assert
         EvaluateData(descriptors, "<input></input>");
@@ -228,7 +227,7 @@ public void AllowsCompatibleTagStructures8()
     public void AllowsCompatibleTagStructures_DirectiveAttribute_SelfClosing()
     {
         // Arrange
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection descriptors =
         [
             TagHelperDescriptorBuilder.CreateEventHandler("InputTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -247,7 +246,7 @@ public void AllowsCompatibleTagStructures_DirectiveAttribute_SelfClosing()
     public void AllowsCompatibleTagStructures_DirectiveAttribute_Void()
     {
         // Arrange
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection descriptors =
         [
             TagHelperDescriptorBuilder.CreateEventHandler("InputTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -430,7 +429,7 @@ public void CreatesErrorForMalformedTagHelper8()
         RunParseTreeRewriterTest("<str<strong></p></strong>", "strong", "p");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> CodeTagHelperAttributes_Descriptors =
+    public static TagHelperCollection CodeTagHelperAttributes_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("PersonTagHelper", "personAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("person"))
@@ -460,85 +459,85 @@ public void CreatesErrorForMalformedTagHelper8()
     [Fact]
     public void UnderstandsMultipartNonStringTagHelperAttributes()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"(() => 123)()\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"(() => 123)()\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes1()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes2()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person birthday=\"DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person birthday=\"DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes3()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"@DateTime.Now.Year\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"@DateTime.Now.Year\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes4()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\" @DateTime.Now.Year\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\" @DateTime.Now.Year\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes5()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person name=\"John\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person name=\"John\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes6()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person name=\"Time: @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person name=\"Time: @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes7()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"1 + @value + 2\" birthday='(bool)@Bag[\"val\"] ? @@DateTime : @DateTime.Now'/>");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"1 + @value + 2\" birthday='(bool)@Bag[\"val\"] ? @@DateTime : @DateTime.Now'/>");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes8()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes9()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @@ @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"Time: @@ @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes10()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"@@BoundStringAttribute\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"12\" birthday=\"DateTime.Now\" name=\"@@BoundStringAttribute\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes11()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"@@@(11+1)\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"@@@(11+1)\" birthday=\"DateTime.Now\" name=\"Time: @DateTime.Now\" />");
     }
 
     [Fact]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes12()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, "<person age=\"@{flag == 0 ? 11 : 12}\" />");
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, "<person age=\"@{flag == 0 ? 11 : 12}\" />");
     }
 
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes13()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var count = "1";
             }
@@ -549,7 +548,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes13()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes14()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var @string = "1";
             }
@@ -560,7 +559,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes14()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes15()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var count = "1";
             }
@@ -571,7 +570,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes15()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes16()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var count = "1";
             }
@@ -582,7 +581,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes16()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes17()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var count = 1;
             }
@@ -593,7 +592,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes17()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes18()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var count = 1;
             }
@@ -604,7 +603,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes18()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes19()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var count = 1;
             }
@@ -615,7 +614,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes19()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes20()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var isAlive = true;
             }
@@ -626,7 +625,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes20()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes21()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var obj = new { Prop = (object)1 };
             }
@@ -637,7 +636,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes21()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10186")]
     public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes22()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             @{ 
                 var obj = new { Prop = (object)1 };
             }
@@ -668,7 +667,7 @@ public void CreatesMarkupCodeSpansForNonStringTagHelperAttributes23()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_01()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag='@new string("1, 2")' />
             """);
     }
@@ -676,7 +675,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_01()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_02()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag="@(new string("1, 2"))" />
             """);
     }
@@ -684,7 +683,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_02()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_03()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag="@new string(@x("1, 2"))" />
             """);
     }
@@ -692,7 +691,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_03()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_04()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag='new string("1, 2")' />
             """);
     }
@@ -700,7 +699,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_04()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_05()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag='new string(@x("1, 2"))' />
             """);
     }
@@ -708,7 +707,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_05()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_06()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag='@new string("1 2")' />
             """);
     }
@@ -716,7 +715,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_06()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_07()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag="@(new string("1 2"))" />
             """);
     }
@@ -724,7 +723,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_07()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_08()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag="@(new string(@x("1 2")))" />
             """);
     }
@@ -732,7 +731,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_08()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_09()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag='"0" + new string("1 2")' />
             """);
     }
@@ -740,7 +739,7 @@ public void CreatesMarkupCodeSpans_EscapedExpression_09()
     [Fact, WorkItem("https://github.com/dotnet/razor/issues/10426")]
     public void CreatesMarkupCodeSpans_EscapedExpression_10()
     {
-        EvaluateData(CodeTagHelperAttributes_Descriptors, """
+        EvaluateData(CodeTagHelperAttributes_TagHelpers, """
             <person tag='"0" + new @String("1 2")' />
             """);
     }
@@ -1057,7 +1056,7 @@ public void UnderstandsEmptyAttributeTagHelpers5()
         RunParseTreeRewriterTest("<p class1=''class2=\"\"class3= />", "p");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> EmptyTagHelperBoundAttribute_Descriptors =
+    public static TagHelperCollection EmptyTagHelperBoundAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("mythTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("myth"))
@@ -1075,85 +1074,85 @@ public void UnderstandsEmptyAttributeTagHelpers5()
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes1()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes2()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    true' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    true' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes3()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    ' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes4()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound=''  bound=\"\" />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound=''  bound=\"\" />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes5()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound=' '  bound=\"  \" />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound=' '  bound=\"  \" />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes6()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='true' bound=  />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='true' bound=  />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes7()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound= name='' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound= name='' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes8()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound= name='  ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound= name='  ' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes9()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='true' name='john' bound= name= />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='true' name='john' bound= name= />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes10()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth BouND='' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth BouND='' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes11()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth BOUND=''    bOUnd=\"\" />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth BOUND=''    bOUnd=\"\" />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes12()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth BOUND= nAMe='john'></myth>");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth BOUND= nAMe='john'></myth>");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes13()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    @true  ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    @true  ' />");
     }
 
     [Fact]
     public void CreatesErrorForEmptyTagHelperBoundAttributes14()
     {
-        EvaluateData(EmptyTagHelperBoundAttribute_Descriptors, "<myth bound='    @(true)  ' />");
+        EvaluateData(EmptyTagHelperBoundAttribute_TagHelpers, "<myth bound='    @(true)  ' />");
     }
 
     [Fact]
@@ -1469,7 +1468,7 @@ public void GeneratesExpectedOutputForUnboundDataDashAttributes_Block7()
         RunParseTreeRewriterTest(document, "input");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> MinimizedAttribute_Descriptors =
+    public static TagHelperCollection MinimizedAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -1525,7 +1524,7 @@ public void UnderstandsMinimizedAttributes_Document1()
         var document = "<input unbound-required />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1535,7 +1534,7 @@ public void UnderstandsMinimizedAttributes_Document2()
         var document = "<p bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1545,7 +1544,7 @@ public void UnderstandsMinimizedAttributes_Document3()
         var document = "<input bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1555,7 +1554,7 @@ public void UnderstandsMinimizedAttributes_Document4()
         var document = "<input bound-required-int />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1565,7 +1564,7 @@ public void UnderstandsMinimizedAttributes_Document5()
         var document = "<p bound-int></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1575,7 +1574,7 @@ public void UnderstandsMinimizedAttributes_Document6()
         var document = "<input int-dictionary/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1585,7 +1584,7 @@ public void UnderstandsMinimizedAttributes_Document7()
         var document = "<input string-dictionary />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1595,7 +1594,7 @@ public void UnderstandsMinimizedAttributes_Document8()
         var document = "<input int-prefix- />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1605,7 +1604,7 @@ public void UnderstandsMinimizedAttributes_Document9()
         var document = "<input string-prefix-/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1615,7 +1614,7 @@ public void UnderstandsMinimizedAttributes_Document10()
         var document = "<input int-prefix-value/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1625,7 +1624,7 @@ public void UnderstandsMinimizedAttributes_Document11()
         var document = "<input string-prefix-value />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1635,7 +1634,7 @@ public void UnderstandsMinimizedAttributes_Document12()
         var document = "<input int-prefix-value='' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1645,7 +1644,7 @@ public void UnderstandsMinimizedAttributes_Document13()
         var document = "<input string-prefix-value=''/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1655,7 +1654,7 @@ public void UnderstandsMinimizedAttributes_Document14()
         var document = "<input int-prefix-value='3'/>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1665,7 +1664,7 @@ public void UnderstandsMinimizedAttributes_Document15()
         var document = "<input string-prefix-value='some string' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1675,7 +1674,7 @@ public void UnderstandsMinimizedAttributes_Document16()
         var document = "<input unbound-required bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1685,7 +1684,7 @@ public void UnderstandsMinimizedAttributes_Document17()
         var document = "<p bound-int bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1695,7 +1694,7 @@ public void UnderstandsMinimizedAttributes_Document18()
         var document = "<input bound-required-int unbound-required bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1705,7 +1704,7 @@ public void UnderstandsMinimizedAttributes_Document19()
         var document = "<p bound-int bound-string bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1715,7 +1714,7 @@ public void UnderstandsMinimizedAttributes_Document20()
         var document = "<input unbound-required class='btn' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1725,7 +1724,7 @@ public void UnderstandsMinimizedAttributes_Document21()
         var document = "<p bound-string class='btn'></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1735,7 +1734,7 @@ public void UnderstandsMinimizedAttributes_Document22()
         var document = "<input class='btn' unbound-required />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1745,7 +1744,7 @@ public void UnderstandsMinimizedAttributes_Document23()
         var document = "<p class='btn' bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1755,7 +1754,7 @@ public void UnderstandsMinimizedAttributes_Document24()
         var document = "<input bound-required-string class='btn' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1765,7 +1764,7 @@ public void UnderstandsMinimizedAttributes_Document25()
         var document = "<input class='btn' bound-required-string />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1775,7 +1774,7 @@ public void UnderstandsMinimizedAttributes_Document26()
         var document = "<input bound-required-int class='btn' />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1785,7 +1784,7 @@ public void UnderstandsMinimizedAttributes_Document27()
         var document = "<p bound-int class='btn'></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1795,7 +1794,7 @@ public void UnderstandsMinimizedAttributes_Document28()
         var document = "<input class='btn' bound-required-int />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1805,7 +1804,7 @@ public void UnderstandsMinimizedAttributes_Document29()
         var document = "<p class='btn' bound-int></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1816,7 +1815,7 @@ public void UnderstandsMinimizedAttributes_Document30()
         var document = $"<input class='{expressionString}' bound-required-int />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1827,7 +1826,7 @@ public void UnderstandsMinimizedAttributes_Document31()
         var document = $"<p class='{expressionString}' bound-int></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1838,7 +1837,7 @@ public void UnderstandsMinimizedAttributes_Document32()
         var document = $"<input    bound-required-int class='{expressionString}'   bound-required-string class='{expressionString}'  unbound-required  />";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1849,7 +1848,7 @@ public void UnderstandsMinimizedAttributes_Document33()
         var document = $"<p    bound-int class='{expressionString}'   bound-string class='{expressionString}'  bound-string></p>";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1862,7 +1861,7 @@ public void UnderstandsMinimizedAttributes_Block1()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1875,7 +1874,7 @@ public void UnderstandsMinimizedAttributes_Block2()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1888,7 +1887,7 @@ public void UnderstandsMinimizedAttributes_Block3()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1901,7 +1900,7 @@ public void UnderstandsMinimizedAttributes_Block4()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1914,7 +1913,7 @@ public void UnderstandsMinimizedAttributes_Block5()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1927,7 +1926,7 @@ public void UnderstandsMinimizedAttributes_Block6()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1940,7 +1939,7 @@ public void UnderstandsMinimizedAttributes_Block7()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1953,7 +1952,7 @@ public void UnderstandsMinimizedAttributes_Block8()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1966,7 +1965,7 @@ public void UnderstandsMinimizedAttributes_Block9()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1979,7 +1978,7 @@ public void UnderstandsMinimizedAttributes_Block10()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -1992,7 +1991,7 @@ public void UnderstandsMinimizedAttributes_Block11()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2005,7 +2004,7 @@ public void UnderstandsMinimizedAttributes_Block12()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2018,7 +2017,7 @@ public void UnderstandsMinimizedAttributes_Block13()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2031,7 +2030,7 @@ public void UnderstandsMinimizedAttributes_Block14()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2044,7 +2043,7 @@ public void UnderstandsMinimizedAttributes_Block15()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2057,7 +2056,7 @@ public void UnderstandsMinimizedAttributes_Block16()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2070,7 +2069,7 @@ public void UnderstandsMinimizedAttributes_Block17()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2083,7 +2082,7 @@ public void UnderstandsMinimizedAttributes_Block18()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2096,7 +2095,7 @@ public void UnderstandsMinimizedAttributes_Block19()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2109,7 +2108,7 @@ public void UnderstandsMinimizedAttributes_Block20()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2122,7 +2121,7 @@ public void UnderstandsMinimizedAttributes_Block21()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2135,7 +2134,7 @@ public void UnderstandsMinimizedAttributes_Block22()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2148,7 +2147,7 @@ public void UnderstandsMinimizedAttributes_Block23()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2161,7 +2160,7 @@ public void UnderstandsMinimizedAttributes_Block24()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2174,7 +2173,7 @@ public void UnderstandsMinimizedAttributes_Block25()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2187,7 +2186,7 @@ public void UnderstandsMinimizedAttributes_Block26()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2200,7 +2199,7 @@ public void UnderstandsMinimizedAttributes_Block27()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2213,7 +2212,7 @@ public void UnderstandsMinimizedAttributes_Block28()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2226,7 +2225,7 @@ public void UnderstandsMinimizedAttributes_Block29()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2240,7 +2239,7 @@ public void UnderstandsMinimizedAttributes_Block30()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2254,7 +2253,7 @@ public void UnderstandsMinimizedAttributes_Block31()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2268,7 +2267,7 @@ public void UnderstandsMinimizedAttributes_Block32()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
@@ -2282,55 +2281,55 @@ public void UnderstandsMinimizedAttributes_Block33()
         document = $"@{{{document}}}";
 
         // Act & Assert
-        EvaluateData(MinimizedAttribute_Descriptors, document);
+        EvaluateData(MinimizedAttribute_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags1()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input unbound-required");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input unbound-required");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags2()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags3()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-int");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-int");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags4()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-int unbound-required bound-required-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-int unbound-required bound-required-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags5()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<p bound-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<p bound-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags6()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<p bound-int");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<p bound-int");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags7()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<p bound-int bound-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<p bound-int bound-string");
     }
 
     [Fact]
     public void UnderstandsMinimizedAttributes_PartialTags8()
     {
-        EvaluateData(MinimizedAttribute_Descriptors, "<input bound-required-int unbound-required bound-required-string<p bound-int bound-string");
+        EvaluateData(MinimizedAttribute_TagHelpers, "<input bound-required-int unbound-required bound-required-string<p bound-int bound-string");
     }
 
     [Fact]
@@ -2338,7 +2337,7 @@ public void UnderstandsMinimizedBooleanBoundAttributes()
     {
         // Arrange
         var document = "<input boundbool boundbooldict-key />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection descriptors =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -2364,7 +2363,7 @@ public void FeatureDisabled_AddsErrorForMinimizedBooleanBoundAttributes()
     {
         // Arrange
         var document = "<input boundbool boundbooldict-key />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection descriptors =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule
@@ -2390,7 +2389,7 @@ public void Rewrites_ComponentDirectiveAttributes()
     {
         // Arrange
         var document = @"<input @bind-value=""Message"" @bind-value:event=""onchange"" />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection descriptors =
         [
             TagHelperDescriptorBuilder.Create(TagHelperKind.Bind, "Bind", ComponentsApi.AssemblyName)
                 .TypeName(
@@ -2434,7 +2433,7 @@ public void Rewrites_MinimizedComponentDirectiveAttributes()
     {
         // Arrange
         var document = @"<input @bind-foo @bind-foo:param />";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection descriptors =
         [
             TagHelperDescriptorBuilder.Create(TagHelperKind.Bind, "Bind", ComponentsApi.AssemblyName)
                 .TypeName(
@@ -2477,7 +2476,8 @@ public void Rewrites_MinimizedComponentDirectiveAttributes()
     public void TagHelper_AttributeAfterRazorComment()
     {
         // Arrange
-        var descriptors = ImmutableArray.Create(
+        TagHelperCollection tagHelpers =
+        [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "TestAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
                 .BoundAttributeDescriptor(attribute => attribute
@@ -2488,10 +2488,11 @@ public void TagHelper_AttributeAfterRazorComment()
                     .Name("not-visible")
                     .PropertyName("NotVisible")
                     .TypeName(typeof(bool).FullName))
-                .Build());
+                .Build()
+        ];
 
         // Act & Assert
-        EvaluateData(descriptors, """
+        EvaluateData(tagHelpers, """
             <p
               attribute-1="true"
               @* visible *@
@@ -2504,7 +2505,8 @@ public void TagHelper_AttributeAfterRazorComment()
     public void TagHelper_MultipleAttributesAfterRazorComment()
     {
         // Arrange
-        var descriptors = ImmutableArray.Create(
+        TagHelperCollection tagHelpers =
+        [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "TestAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
                 .BoundAttributeDescriptor(attribute => attribute
@@ -2519,10 +2521,11 @@ public void TagHelper_MultipleAttributesAfterRazorComment()
                     .Name("attr-3")
                     .PropertyName("Attr3")
                     .TypeName(typeof(string).FullName))
-                .Build());
+                .Build()
+        ];
 
         // Act & Assert
-        EvaluateData(descriptors, """
+        EvaluateData(tagHelpers, """
             <p attr-1="first" @* comment *@ attr-2="second" attr-3="third"></p>
             """);
     }
@@ -2531,7 +2534,8 @@ public void TagHelper_MultipleAttributesAfterRazorComment()
     public void TagHelper_MultipleInterleavedRazorComments()
     {
         // Arrange
-        var descriptors = ImmutableArray.Create(
+        TagHelperCollection tagHelpers =
+        [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "TestAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("input"))
                 .BoundAttributeDescriptor(attribute => attribute
@@ -2542,10 +2546,11 @@ public void TagHelper_MultipleInterleavedRazorComments()
                     .Name("value")
                     .PropertyName("Value")
                     .TypeName(typeof(string).FullName))
-                .Build());
+                .Build()
+        ];
 
         // Act & Assert
-        EvaluateData(descriptors, """
+        EvaluateData(tagHelpers, """
             <input @* comment1 *@ type="text" @* comment2 *@ value="test" @* comment3 *@ />
             """);
     }
@@ -2554,7 +2559,8 @@ public void TagHelper_MultipleInterleavedRazorComments()
     public void TagHelper_MinimizedAttributeAfterRazorComment()
     {
         // Arrange
-        var descriptors = ImmutableArray.Create(
+        TagHelperCollection tagHelpers =
+        [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "TestAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("input"))
                 .BoundAttributeDescriptor(attribute => attribute
@@ -2565,10 +2571,11 @@ public void TagHelper_MinimizedAttributeAfterRazorComment()
                     .Name("checked")
                     .PropertyName("Checked")
                     .TypeName(typeof(bool).FullName))
-                .Build());
+                .Build()
+        ];
 
         // Act & Assert
-        EvaluateData(descriptors, """
+        EvaluateData(tagHelpers, """
             <input type="checkbox" @* comment *@ checked />
             """);
     }
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperParseTreeRewriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperParseTreeRewriterTest.cs
index 1af193083e2..5047a11285b 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperParseTreeRewriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperParseTreeRewriterTest.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Xunit;
@@ -66,7 +65,7 @@ public void GetAttributeNameValuePairs_ParsesPairsCorrectly(
         Assert.Equal(expectedPairs, pairs);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> PartialRequiredParentTags_Descriptors =
+    public static readonly TagHelperCollection PartialRequiredParentTags_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("StrongTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
@@ -84,45 +83,45 @@ public void GetAttributeNameValuePairs_ParsesPairsCorrectly(
     public void UnderstandsPartialRequiredParentTags1()
     {
         var document = "<p><strong>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags2()
     {
         var document = "<p><strong></strong>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags3()
     {
         var document = "<p><strong></p><strong>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags4()
     {
         var document = "<<p><<strong></</strong</strong></p>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags5()
     {
         var document = "<<p><<strong></</strong></strong></p>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsPartialRequiredParentTags6()
     {
         var document = "<<p><<custom></<</custom></custom></p>";
-        EvaluateData(PartialRequiredParentTags_Descriptors, document);
+        EvaluateData(PartialRequiredParentTags_TagHelpers, document);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> NestedVoidSelfClosingRequiredParent_Descriptors =
+    public static readonly TagHelperCollection NestedVoidSelfClosingRequiredParent_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -145,7 +144,7 @@ public void UnderstandsPartialRequiredParentTags6()
             .Build(),
     ];
 
-    public static ImmutableArray<TagHelperDescriptor> CatchAllAttribute_Descriptors =
+    public static readonly TagHelperCollection CatchAllAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateEventHandler("InputTagHelper1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
@@ -161,66 +160,66 @@ public void UnderstandsPartialRequiredParentTags6()
     public void UnderstandsInvalidHtml()
     {
         var document = @"<a onclick=""() => {}""><a/></a><strong>Miscolored!</strong>";
-        EvaluateData(CatchAllAttribute_Descriptors, document);
+        EvaluateData(CatchAllAttribute_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent1()
     {
         var document = "<input><strong></strong>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent2()
     {
         var document = "<p><input><strong></strong></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent3()
     {
         var document = "<p><br><strong></strong></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent4()
     {
         var document = "<p><p><br></p><strong></strong></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent5()
     {
         var document = "<input><strong></strong>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent6()
     {
         var document = "<p><input /><strong /></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent7()
     {
         var document = "<p><br /><strong /></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedVoidSelfClosingRequiredParent8()
     {
         var document = "<p><p><br /></p><strong /></p>";
-        EvaluateData(NestedVoidSelfClosingRequiredParent_Descriptors, document);
+        EvaluateData(NestedVoidSelfClosingRequiredParent_TagHelpers, document);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> NestedRequiredParent_Descriptors =
+    public static readonly TagHelperCollection NestedRequiredParent_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("StrongTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -241,35 +240,35 @@ public void UnderstandsNestedVoidSelfClosingRequiredParent8()
     public void UnderstandsNestedRequiredParent1()
     {
         var document = "<strong></strong>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent2()
     {
         var document = "<p><strong></strong></p>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent3()
     {
         var document = "<div><strong></strong></div>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent4()
     {
         var document = "<strong><strong></strong></strong>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
     public void UnderstandsNestedRequiredParent5()
     {
         var document = "<p><strong><strong></strong></strong></p>";
-        EvaluateData(NestedRequiredParent_Descriptors, document);
+        EvaluateData(NestedRequiredParent_TagHelpers, document);
     }
 
     [Fact]
@@ -277,7 +276,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildren()
     {
         // Arrange
         var documentContent = "<th:p><th:strong></th:strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -290,7 +289,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildren()
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -300,7 +299,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildrenAndRequireParent()
     {
         // Arrange
         var documentContent = "<th:p><th:strong></th:strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -313,7 +312,7 @@ public void UnderstandsTagHelperPrefixAndAllowedChildrenAndRequireParent()
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -324,7 +323,7 @@ public void InvalidStructure_UnderstandsTHPrefixAndAllowedChildrenAndRequirePare
         // Rewrite_InvalidStructure_UnderstandsTagHelperPrefixAndAllowedChildrenAndRequireParent
         // Arrange
         var documentContent = "<th:p></th:strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -337,7 +336,7 @@ public void InvalidStructure_UnderstandsTHPrefixAndAllowedChildrenAndRequirePare
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -347,7 +346,7 @@ public void NonTagHelperChild_UnderstandsTagHelperPrefixAndAllowedChildren()
     {
         // Arrange
         var documentContent = "<th:p><strong></strong></th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -357,7 +356,7 @@ public void NonTagHelperChild_UnderstandsTagHelperPrefixAndAllowedChildren()
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             documentContent,
             tagHelperPrefix: "th:");
     }
@@ -429,7 +428,7 @@ public void CanHandleInvalidChildrenWithWhitespace()
                 </strong>
             </p>
             """;
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -438,7 +437,7 @@ public void CanHandleInvalidChildrenWithWhitespace()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -446,7 +445,7 @@ public void RecoversWhenRequiredAttributeMismatchAndRestrictedChildren()
     {
         // Arrange
         var documentContent = "<strong required><strong></strong></strong>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("StrongTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -458,7 +457,7 @@ public void RecoversWhenRequiredAttributeMismatchAndRestrictedChildren()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -466,7 +465,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren_OneNull()
     {
         // Arrange
         var documentContent = "<p><strong>Hello World</strong><br></p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -488,7 +487,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren_OneNull()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -496,7 +495,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren()
     {
         // Arrange
         var documentContent = "<p><strong>Hello World</strong><br></p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -518,7 +517,7 @@ public void CanHandleMultipleTagHelpersWithAllowedChildren()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -526,10 +525,10 @@ public void UnderstandsAllowedChildren1()
     {
         // Arrange
         var documentContent = "<p><br /></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -541,10 +540,10 @@ public void UnderstandsAllowedChildren2()
             <br />
             </p>
             """;
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -552,10 +551,10 @@ public void UnderstandsAllowedChildren3()
     {
         // Arrange
         var documentContent = "<p><br></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -563,10 +562,10 @@ public void UnderstandsAllowedChildren4()
     {
         // Arrange
         var documentContent = "<p>Hello</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -574,10 +573,10 @@ public void UnderstandsAllowedChildren5()
     {
         // Arrange
         var documentContent = "<p><hr /></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["br", "strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["br", "strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -585,10 +584,10 @@ public void UnderstandsAllowedChildren6()
     {
         // Arrange
         var documentContent = "<p><br>Hello</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -596,10 +595,10 @@ public void UnderstandsAllowedChildren7()
     {
         // Arrange
         var documentContent = "<p><strong>Title:</strong><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -607,10 +606,10 @@ public void UnderstandsAllowedChildren8()
     {
         // Arrange
         var documentContent = "<p><strong>Title:</strong><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong", "br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong", "br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -618,10 +617,10 @@ public void UnderstandsAllowedChildren9()
     {
         // Arrange
         var documentContent = "<p>  <strong>Title:</strong>  <br />  Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong", "br"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong", "br"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -629,10 +628,10 @@ public void UnderstandsAllowedChildren10()
     {
         // Arrange
         var documentContent = "<p><strong>Title:<br><em>A Very Cool</em></strong><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -640,10 +639,10 @@ public void UnderstandsAllowedChildren11()
     {
         // Arrange
         var documentContent = "<p><custom>Title:<br><em>A Very Cool</em></custom><br />Something</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -651,10 +650,10 @@ public void UnderstandsAllowedChildren12()
     {
         // Arrange
         var documentContent = "<p></</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -662,10 +661,10 @@ public void UnderstandsAllowedChildren13()
     {
         // Arrange
         var documentContent = "<p><</p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -673,13 +672,13 @@ public void UnderstandsAllowedChildren14()
     {
         // Arrange
         var documentContent = "<p><custom><br>:<strong><strong>Hello</strong></strong>:<input></custom></p>";
-        var descriptors = GetAllowedChildrenTagHelperDescriptors(["custom", "strong"]);
+        var tagHelpers = GetAllowedChildrenTagHelpers(["custom", "strong"]);
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
-    private static ImmutableArray<TagHelperDescriptor> GetAllowedChildrenTagHelperDescriptors(string[] allowedChildren)
+    private static TagHelperCollection GetAllowedChildrenTagHelpers(string[] allowedChildren)
     {
         var pTagHelperBuilder = TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"));
@@ -722,13 +721,13 @@ public void AllowsSimpleHtmlCommentsAsChildren()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -747,14 +746,14 @@ public void DoesntAllowSimpleHtmlCommentsAsChildrenWhenFeatureFlagIsOff()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
         EvaluateData(
-            descriptors,
+            tagHelpers,
             document,
             languageVersion: RazorLanguageVersion.Version_2_0,
             fileKind: RazorFileKind.Legacy);
@@ -778,13 +777,13 @@ public void FailsForContentWithCommentsAsChildren()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -804,13 +803,13 @@ public void AllowsRazorCommentsAsChildren()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -833,13 +832,13 @@ public void AllowsRazorMarkupInHtmlComment()
             pTagHelperBuilder.AllowChildTag(childTag);
         }
 
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             pTagHelperBuilder.Build()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, document);
+        EvaluateData(tagHelpers, document);
     }
 
     [Fact]
@@ -847,7 +846,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAll()
     {
         // Arrange
         var documentContent = "<p></</p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -859,7 +858,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAll()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -867,7 +866,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAllWithPrefix()
     {
         // Arrange
         var documentContent = "<th:p></</th:p>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
@@ -879,7 +878,7 @@ public void UnderstandsNullTagNameWithAllowedChildrenForCatchAllWithPrefix()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent, "th:");
+        EvaluateData(tagHelpers, documentContent, "th:");
     }
 
     [Fact]
@@ -887,7 +886,7 @@ public void CanHandleStartTagOnlyTagTagMode()
     {
         // Arrange
         var documentContent = "<input>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -898,7 +897,7 @@ public void CanHandleStartTagOnlyTagTagMode()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -906,7 +905,7 @@ public void CreatesErrorForWithoutEndTagTagStructureForEndTags()
     {
         // Arrange
         var documentContent = "</input>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -917,7 +916,7 @@ public void CreatesErrorForWithoutEndTagTagStructureForEndTags()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
     [Fact]
@@ -925,7 +924,7 @@ public void CreatesErrorForInconsistentTagStructures()
     {
         // Arrange
         var documentContent = "<input>";
-        ImmutableArray<TagHelperDescriptor> descriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("InputTagHelper1", "SomeAssembly")
                 .TagMatchingRuleDescriptor(rule =>
@@ -942,10 +941,10 @@ public void CreatesErrorForInconsistentTagStructures()
         ];
 
         // Act & Assert
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> RequiredAttribute_Descriptors =
+    public static readonly TagHelperCollection RequiredAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -971,184 +970,184 @@ public void CreatesErrorForInconsistentTagStructures()
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly1()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly2()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p></p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p></p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly3()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly4()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div></div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div></div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly5()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly6()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"@DateTime.Now\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"@DateTime.Now\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly7()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly8()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"@DateTime.Now\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"@DateTime.Now\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly9()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\">words<strong>and</strong>spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\">words<strong>and</strong>spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly10()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"hi\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"hi\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly11()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"@DateTime.Now\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"@DateTime.Now\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly12()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"hi\">words and spaces</strong>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"hi\">words and spaces</strong>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly13()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<strong catchAll=\"@DateTime.Now\">words and spaces</strong>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<strong catchAll=\"@DateTime.Now\">words and spaces</strong>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly14()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly15()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div class=\"btn\"></div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div class=\"btn\"></div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly16()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p notRequired=\"a\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p notRequired=\"a\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly17()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p notRequired=\"@DateTime.Now\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p notRequired=\"@DateTime.Now\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly18()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p notRequired=\"a\" class=\"btn\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p notRequired=\"a\" class=\"btn\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly19()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly20()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"@DateTime.Now\" class=\"btn\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"@DateTime.Now\" class=\"btn\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly21()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\">words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\">words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly22()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\">words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\">words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly23()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\">words<strong>and</strong>spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\">words<strong>and</strong>spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly24()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\" catchAll=\"hi\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\" catchAll=\"hi\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly25()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<p class=\"btn\" catchAll=\"hi\">words and spaces</p>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<p class=\"btn\" catchAll=\"hi\">words and spaces</p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly26()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"hi\" />");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"hi\" />");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly27()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly28()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"@@hi\" >words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"@@hi\" >words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly29()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\" catchAll=\"@DateTime.Now\" >words and spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"@DateTime.Now\" class=\"@DateTime.Now\" catchAll=\"@DateTime.Now\" >words and spaces</div>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly30()
     {
-        EvaluateData(RequiredAttribute_Descriptors, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words<strong>and</strong>spaces</div>");
+        EvaluateData(RequiredAttribute_TagHelpers, "<div style=\"\" class=\"btn\" catchAll=\"hi\" >words<strong>and</strong>spaces</div>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> NestedRequiredAttribute_Descriptors =
+    public static readonly TagHelperCollection NestedRequiredAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -1167,64 +1166,64 @@ public void RequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly30()
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly1()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><p></p></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><p></p></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly2()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><strong></strong></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><strong></strong></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly3()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><strong><p></p></strong></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><strong><p></p></strong></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly4()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><p><strong></strong></p></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><p><strong></strong></p></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly5()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><strong catchAll=\"hi\"><p></p></strong></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><strong catchAll=\"hi\"><p></p></strong></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly6()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><p class=\"btn\"><strong></strong></p></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><p class=\"btn\"><strong></strong></p></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly7()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><p class=\"btn\"><p></p></p></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><p class=\"btn\"><p></p></p></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly8()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><strong catchAll=\"hi\"><strong></strong></strong></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><strong catchAll=\"hi\"><strong></strong></strong></strong>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly9()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<p class=\"btn\"><p><p><p class=\"btn\"><p></p></p></p></p></p>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<p class=\"btn\"><p><p><p class=\"btn\"><p></p></p></p></p></p>");
     }
 
     [Fact]
     public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly10()
     {
-        EvaluateData(NestedRequiredAttribute_Descriptors, "<strong catchAll=\"hi\"><strong><strong><strong catchAll=\"hi\"><strong></strong></strong></strong></strong></strong>");
+        EvaluateData(NestedRequiredAttribute_TagHelpers, "<strong catchAll=\"hi\"><strong><strong><strong catchAll=\"hi\"><strong></strong></strong></strong></strong></strong>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> MalformedRequiredAttribute_Descriptors =
+    public static readonly TagHelperCollection MalformedRequiredAttribute_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule =>
@@ -1237,71 +1236,71 @@ public void NestedRequiredAttributeDescriptorsCreateTagHelperBlocksCorrectly10()
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly1()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly2()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\"");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\"");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly3()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\"");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\"");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly4()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p></p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p></p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly5()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\"></p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\"></p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly6()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\"></p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\"></p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly7()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\" <p>");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\" <p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly8()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\" <p>");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\" <p>");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly9()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p class=\"btn\" </p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p class=\"btn\" </p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly10()
     {
-        EvaluateData(MalformedRequiredAttribute_Descriptors, "<p notRequired=\"hi\" class=\"btn\" </p");
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, "<p notRequired=\"hi\" class=\"btn\" </p");
     }
 
     [Fact]
     public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly11()
     {
         var document = "<p class='foo'>@if(true){</p>}</p>";
-        EvaluateData(MalformedRequiredAttribute_Descriptors, document);
+        EvaluateData(MalformedRequiredAttribute_TagHelpers, document);
     }
 
-    public static ImmutableArray<TagHelperDescriptor> PrefixedTagHelperColon_Descriptors =
+    public static readonly TagHelperCollection PrefixedTagHelperColon_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("mythTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("myth"))
@@ -1316,7 +1315,7 @@ public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly1
             .Build()
     ];
 
-    public static ImmutableArray<TagHelperDescriptor> PrefixedTagHelperCatchAll_Descriptors =
+    public static readonly TagHelperCollection PrefixedTagHelperCatchAll_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("mythTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
@@ -1326,67 +1325,67 @@ public void RequiredAttributeDescriptorsCreateMalformedTagHelperBlocksCorrectly1
     [Fact]
     public void AllowsPrefixedTagHelpers1()
     {
-        EvaluateData(PrefixedTagHelperCatchAll_Descriptors, "<th: />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperCatchAll_TagHelpers, "<th: />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers2()
     {
-        EvaluateData(PrefixedTagHelperCatchAll_Descriptors, "<th:>words and spaces</th:>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperCatchAll_TagHelpers, "<th:>words and spaces</th:>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers3()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers4()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth></th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth></th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers5()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth><th:my2th></th:my2th></th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth><th:my2th></th:my2th></th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers6()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<!th:myth />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<!th:myth />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers7()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<!th:myth></!th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<!th:myth></!th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers8()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth class=\"btn\" />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth class=\"btn\" />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers9()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth2 class=\"btn\" />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth2 class=\"btn\" />", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers10()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth class=\"btn\">words and spaces</th:myth>", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth class=\"btn\">words and spaces</th:myth>", tagHelperPrefix: "th:");
     }
 
     [Fact]
     public void AllowsPrefixedTagHelpers11()
     {
-        EvaluateData(PrefixedTagHelperColon_Descriptors, "<th:myth2 bound=\"@DateTime.Now\" />", tagHelperPrefix: "th:");
+        EvaluateData(PrefixedTagHelperColon_TagHelpers, "<th:myth2 bound=\"@DateTime.Now\" />", tagHelperPrefix: "th:");
     }
 
     [Fact]
@@ -1911,7 +1910,7 @@ public void HandlesNonTagHelperStartAndEndVoidTags_Correctly()
         RunParseTreeRewriterTest("<input>Foo</input>");
     }
 
-    public static ImmutableArray<TagHelperDescriptor> CaseSensitive_Descriptors =
+    public static readonly TagHelperCollection CaseSensitive_TagHelpers =
     [
         TagHelperDescriptorBuilder.CreateTagHelper("pTagHelper", "SomeAssembly")
             .SetCaseSensitive()
@@ -1936,30 +1935,30 @@ public void HandlesNonTagHelperStartAndEndVoidTags_Correctly()
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly1()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<p class='foo' catchAll></p>");
+        EvaluateData(CaseSensitive_TagHelpers, "<p class='foo' catchAll></p>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly2()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<p CLASS='foo' CATCHAll></p>");
+        EvaluateData(CaseSensitive_TagHelpers, "<p CLASS='foo' CATCHAll></p>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly3()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<P class='foo' CATCHAll></P>");
+        EvaluateData(CaseSensitive_TagHelpers, "<P class='foo' CATCHAll></P>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly4()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<P class='foo'></P>");
+        EvaluateData(CaseSensitive_TagHelpers, "<P class='foo'></P>");
     }
 
     [Fact]
     public void HandlesCaseSensitiveTagHelpersCorrectly5()
     {
-        EvaluateData(CaseSensitive_Descriptors, "<p Class='foo'></p>");
+        EvaluateData(CaseSensitive_TagHelpers, "<p Class='foo'></p>");
     }
 }
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperRewritingTestBase.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperRewritingTestBase.cs
index aca41009202..6b163169ab5 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperRewritingTestBase.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Legacy/TagHelperRewritingTestBase.cs
@@ -1,10 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using System;
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using Xunit;
 
@@ -12,39 +9,38 @@ namespace Microsoft.AspNetCore.Razor.Language.Legacy;
 
 public class TagHelperRewritingTestBase() : ParserTestBase(layer: TestProject.Layer.Compiler)
 {
-    internal void RunParseTreeRewriterTest(string documentContent, params string[] tagNames)
+    internal void RunParseTreeRewriterTest(string documentContent, params ImmutableArray<string> tagNames)
     {
-        var descriptors = BuildDescriptors(tagNames);
+        var tagHelpers = BuildTagHelpers(tagNames);
 
-        EvaluateData(descriptors, documentContent);
+        EvaluateData(tagHelpers, documentContent);
     }
 
-    internal ImmutableArray<TagHelperDescriptor> BuildDescriptors(params string[] tagNames)
+    internal static TagHelperCollection BuildTagHelpers(params ImmutableArray<string> tagNames)
     {
-        var descriptors = new List<TagHelperDescriptor>();
-
-        foreach (var tagName in tagNames)
+        return TagHelperCollection.Build(tagNames, (ref builder, tagNames) =>
         {
-            var descriptor = TagHelperDescriptorBuilder.CreateTagHelper(tagName + "taghelper", "SomeAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName(tagName))
-                .Build();
-            descriptors.Add(descriptor);
-        }
-
-        return descriptors.ToImmutableArray();
+            foreach (var tagName in tagNames)
+            {
+                var tagHelper = TagHelperDescriptorBuilder.CreateTagHelper(tagName + "taghelper", "SomeAssembly")
+                    .TagMatchingRuleDescriptor(rule => rule.RequireTagName(tagName))
+                    .Build();
+                builder.Add(tagHelper);
+            }
+        });
     }
 
     internal void EvaluateData(
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         string documentContent,
-        string tagHelperPrefix = null,
-        RazorLanguageVersion languageVersion = null,
+        string? tagHelperPrefix = null,
+        RazorLanguageVersion? languageVersion = null,
         RazorFileKind? fileKind = null,
-        Action<RazorParserOptions.Builder> configureParserOptions = null)
+        Action<RazorParserOptions.Builder>? configureParserOptions = null)
     {
         var syntaxTree = ParseDocument(languageVersion, documentContent, directives: default, fileKind: fileKind, configureParserOptions: configureParserOptions);
 
-        var binder = new TagHelperBinder(tagHelperPrefix, descriptors);
+        var binder = new TagHelperBinder(tagHelperPrefix, tagHelpers);
         var rewrittenTree = TagHelperParseTreeRewriter.Rewrite(syntaxTree, binder);
 
         Assert.Equal(syntaxTree.Root.Width, rewrittenTree.Root.Width);
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/RazorCodeDocumentExtensionsTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/RazorCodeDocumentExtensionsTest.cs
index 0948fa7b0d7..22865048809 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/RazorCodeDocumentExtensionsTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/RazorCodeDocumentExtensionsTest.cs
@@ -32,10 +32,10 @@ public void GetAndSetTagHelpers_ReturnsTagHelpers()
         // Arrange
         var codeDocument = TestRazorCodeDocument.CreateEmpty();
 
-        var expected = new[]
-        {
+        TagHelperCollection expected =
+        [
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly").Build()
-        };
+        ];
 
         codeDocument.SetTagHelpers(expected);
 
@@ -52,7 +52,7 @@ public void GetAndSetTagHelperContext_ReturnsTagHelperContext()
         // Arrange
         var codeDocument = TestRazorCodeDocument.CreateEmpty();
 
-        var expected = TagHelperDocumentContext.Create(prefix: null, tagHelpers: []);
+        var expected = TagHelperDocumentContext.Create(tagHelpers: []);
         codeDocument.SetTagHelperContext(expected);
 
         // Act
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TagHelperBinderTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TagHelperBinderTest.cs
index b5e72bb7d24..6c9f4738086 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TagHelperBinderTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TagHelperBinderTest.cs
@@ -1,12 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Linq;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Razor.Language;
@@ -20,25 +17,26 @@ public void GetBinding_ReturnsBindingWithInformation()
         var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors = [divTagHelper];
+        TagHelperCollection expectedTagHelpers = [divTagHelper];
         var expectedAttributes = ImmutableArray.Create(
             new KeyValuePair<string, string>("class", "something"));
-        var tagHelperBinder = new TagHelperBinder("th:", expectedDescriptors);
+        var binder = new TagHelperBinder("th:", expectedTagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "th:div",
             attributes: expectedAttributes,
             parentTagName: "body",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.Equal<TagHelperDescriptor>(expectedDescriptors, bindingResult.Descriptors);
-        Assert.Equal("th:div", bindingResult.TagName);
-        Assert.Equal("body", bindingResult.ParentTagName);
-        Assert.Equal<KeyValuePair<string, string>>(expectedAttributes, bindingResult.Attributes);
-        Assert.Equal("th:", bindingResult.TagNamePrefix);
-        Assert.Equal<TagMatchingRuleDescriptor>(divTagHelper.TagMatchingRules, bindingResult.GetBoundRules(divTagHelper));
+        Assert.NotNull(binding);
+        Assert.Equal(expectedTagHelpers, binding.TagHelpers);
+        Assert.Equal("th:div", binding.TagName);
+        Assert.Equal("body", binding.ParentTagName);
+        Assert.Equal<KeyValuePair<string, string>>(expectedAttributes, binding.Attributes);
+        Assert.Equal("th:", binding.TagNamePrefix);
+        Assert.Equal<TagMatchingRuleDescriptor>(divTagHelper.TagMatchingRules, binding.GetBoundRules(divTagHelper));
     }
 
     [Fact]
@@ -50,37 +48,37 @@ public void GetBinding_With_Multiple_TagNameRules_SingleHelper()
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("a"))
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("img"))
             .Build();
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors = [multiTagHelper];
-        var tagHelperBinder = new TagHelperBinder("", expectedDescriptors);
+        TagHelperCollection expectedTagHelpers = [multiTagHelper];
+        var binder = new TagHelperBinder("", expectedTagHelpers);
 
         TestTagName("div", multiTagHelper.TagMatchingRules[0]);
         TestTagName("a", multiTagHelper.TagMatchingRules[1]);
         TestTagName("img", multiTagHelper.TagMatchingRules[2]);
         TestTagName("p", null);
         TestTagName("*", null);
-        void TestTagName(string tagName, TagMatchingRuleDescriptor expectedBindingResult)
+
+        void TestTagName(string tagName, TagMatchingRuleDescriptor? expectedBindingResult)
         {
             // Act
-            var bindingResult = tagHelperBinder.GetBinding(
-
+            var binding = binder.GetBinding(
                 tagName: tagName,
-                attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+                attributes: [],
                 parentTagName: "body",
                 parentIsTagHelper: false);
 
             // Assert
             if (expectedBindingResult == null)
             {
-                Assert.Null(bindingResult);
+                Assert.Null(binding);
                 return;
             }
             else
             {
-                Assert.NotNull(bindingResult);
-                Assert.Equal<TagHelperDescriptor>(expectedDescriptors, bindingResult.Descriptors);
+                Assert.NotNull(binding);
+                Assert.Equal(expectedTagHelpers, binding.TagHelpers);
 
-                Assert.Equal(tagName, bindingResult.TagName);
-                var mapping = Assert.Single(bindingResult.GetBoundRules(multiTagHelper));
+                Assert.Equal(tagName, binding.TagName);
+                var mapping = Assert.Single(binding.GetBoundRules(multiTagHelper));
                 Assert.Equal(expectedBindingResult, mapping);
             }
         }
@@ -102,7 +100,7 @@ public void GetBinding_With_Multiple_TagNameRules_MultipleHelpers()
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("table"))
             .Build();
 
-        var tagHelperBinder = new TagHelperBinder("", [multiTagHelper1, multiTagHelper2]);
+        var binder = new TagHelperBinder("", [multiTagHelper1, multiTagHelper2]);
 
         TestTagName("div", [multiTagHelper1, multiTagHelper2], [multiTagHelper1.TagMatchingRules[0], multiTagHelper2.TagMatchingRules[0]]);
         TestTagName("a", [multiTagHelper1], [multiTagHelper1.TagMatchingRules[1]]);
@@ -111,38 +109,38 @@ public void GetBinding_With_Multiple_TagNameRules_MultipleHelpers()
         TestTagName("table", [multiTagHelper2], [multiTagHelper2.TagMatchingRules[2]]);
         TestTagName("*", null, null);
 
-
-        void TestTagName(string tagName, TagHelperDescriptor[] expectedDescriptors, TagMatchingRuleDescriptor[] expectedBindingResults)
+        void TestTagName(string tagName, TagHelperCollection? expectedTagHelpers, TagMatchingRuleDescriptor[]? expectedBindingResults)
         {
             // Act
-            var bindingResult = tagHelperBinder.GetBinding(
+            var binding = binder.GetBinding(
                 tagName: tagName,
                 attributes: [],
                 parentTagName: "body",
                 parentIsTagHelper: false);
 
             // Assert
-            if (expectedDescriptors is null)
+            if (expectedTagHelpers is null)
             {
-                Assert.Null(bindingResult);
+                Assert.Null(binding);
             }
             else
             {
-                Assert.NotNull(bindingResult);
-                Assert.Equal(expectedDescriptors, bindingResult.Descriptors);
+                Assert.NotNull(binding);
+                Assert.Equal(expectedTagHelpers, binding.TagHelpers);
+                Assert.NotNull(expectedBindingResults);
 
-                Assert.Equal(tagName, bindingResult.TagName);
+                Assert.Equal(tagName, binding.TagName);
 
-                for (int i = 0; i < expectedDescriptors.Length; i++)
+                for (var i = 0; i < expectedTagHelpers.Count; i++)
                 {
-                    var mapping = Assert.Single(bindingResult.GetBoundRules(expectedDescriptors[i]));
+                    var mapping = Assert.Single(binding.GetBoundRules(expectedTagHelpers[i]));
                     Assert.Equal(expectedBindingResults[i], mapping);
                 }
             }
         }
     }
 
-    public static TheoryData RequiredParentData
+    public static TheoryData<string, string, TagHelperCollection, TagHelperCollection> RequiredParentData
     {
         get
         {
@@ -163,37 +161,34 @@ public static TheoryData RequiredParentData
                     .RequireParentTag("p"))
                 .Build();
 
-            return new TheoryData<
-                string, // tagName
-                string, // parentTagName
-                ImmutableArray<TagHelperDescriptor>, // availableDescriptors
-                ImmutableArray<TagHelperDescriptor>> // expectedDescriptors
+            // tagName, parentTagName, availableTagHelpers, expectedTagHelpers
+            return new()
+            {
+                {
+                    "strong",
+                    "p",
+                    [strongPDivParent],
+                    [strongPDivParent]
+                },
                 {
-                    {
-                        "strong",
-                        "p",
-                        [strongPDivParent],
-                        [strongPDivParent]
-                    },
-                    {
-                        "strong",
-                        "div",
-                        [strongPDivParent, catchAllPParent],
-                        [strongPDivParent]
-                    },
-                    {
-                        "strong",
-                        "p",
-                        [strongPDivParent, catchAllPParent],
-                        [strongPDivParent, catchAllPParent]
-                    },
-                    {
-                        "custom",
-                        "p",
-                        [strongPDivParent, catchAllPParent],
-                        [catchAllPParent]
-                    },
-                };
+                    "strong",
+                    "div",
+                    [strongPDivParent, catchAllPParent],
+                    [strongPDivParent]
+                },
+                {
+                    "strong",
+                    "p",
+                    [strongPDivParent, catchAllPParent],
+                    [strongPDivParent, catchAllPParent]
+                },
+                {
+                    "custom",
+                    "p",
+                    [strongPDivParent, catchAllPParent],
+                    [catchAllPParent]
+                }
+            };
         }
     }
 
@@ -202,24 +197,25 @@ public static TheoryData RequiredParentData
     public void GetBinding_ReturnsBindingResultWithDescriptorsParentTags(
         string tagName,
         string parentTagName,
-        ImmutableArray<TagHelperDescriptor> availableDescriptors,
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors)
+        TagHelperCollection availableTagHelpers,
+        TagHelperCollection expectedTagHelpers)
     {
         // Arrange
-        var tagHelperBinder = new TagHelperBinder(null, availableDescriptors);
+        var binder = new TagHelperBinder(null, availableTagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName,
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: parentTagName,
             parentIsTagHelper: false);
 
         // Assert
-        Assert.Equal<TagHelperDescriptor>(expectedDescriptors, bindingResult.Descriptors);
+        Assert.NotNull(binding);
+        Assert.Equal(expectedTagHelpers, binding.TagHelpers);
     }
 
-    public static TheoryData RequiredAttributeData
+    public static TheoryData<string, ImmutableArray<KeyValuePair<string, string>>, TagHelperCollection, TagHelperCollection?> RequiredAttributeData
     {
         get
         {
@@ -257,100 +253,97 @@ public static TheoryData RequiredAttributeData
                     .RequireAttributeDescriptor(attribute => attribute
                         .Name("prefix-", RequiredAttributeNameComparison.PrefixMatch)))
                 .Build();
-            ImmutableArray<TagHelperDescriptor> defaultAvailableDescriptors =
+            TagHelperCollection defaultAvailableDescriptors =
                 [divDescriptor, inputDescriptor, catchAllDescriptor, catchAllDescriptor2];
-            ImmutableArray<TagHelperDescriptor> defaultWildcardDescriptors =
+            TagHelperCollection defaultWildcardDescriptors =
                 [inputWildcardPrefixDescriptor, catchAllWildcardPrefixDescriptor];
             Func<string, KeyValuePair<string, string>> kvp =
                 (name) => new KeyValuePair<string, string>(name, "test value");
 
-            return new TheoryData<
-                string, // tagName
-                ImmutableArray<KeyValuePair<string, string>>, // providedAttributes
-                ImmutableArray<TagHelperDescriptor>, // availableDescriptors
-                ImmutableArray<TagHelperDescriptor>> // expectedDescriptors
+            // tagName, providedAttributes, availableTagHelpers, expectedTagHelpers
+            return new()
+            {
+                {
+                    "div",
+                    ImmutableArray.Create(kvp("custom")),
+                    defaultAvailableDescriptors,
+                    default
+                },
+                { "div", ImmutableArray.Create(kvp("style")), defaultAvailableDescriptors, [divDescriptor] },
+                { "div", ImmutableArray.Create(kvp("class")), defaultAvailableDescriptors, [catchAllDescriptor] },
+                {
+                    "div",
+                    ImmutableArray.Create(kvp("class"), kvp("style")),
+                    defaultAvailableDescriptors,
+                    [divDescriptor, catchAllDescriptor]
+                },
+                {
+                    "div",
+                    ImmutableArray.Create(kvp("class"), kvp("style"), kvp("custom")),
+                    defaultAvailableDescriptors,
+                    [divDescriptor, catchAllDescriptor, catchAllDescriptor2]
+                },
                 {
-                    {
-                        "div",
-                        ImmutableArray.Create(kvp("custom")),
-                        defaultAvailableDescriptors,
-                        default
-                    },
-                    { "div", ImmutableArray.Create(kvp("style")), defaultAvailableDescriptors, [divDescriptor] },
-                    { "div", ImmutableArray.Create(kvp("class")), defaultAvailableDescriptors, [catchAllDescriptor] },
-                    {
-                        "div",
-                        ImmutableArray.Create(kvp("class"), kvp("style")),
-                        defaultAvailableDescriptors,
-                        [divDescriptor, catchAllDescriptor]
-                    },
-                    {
-                        "div",
-                        ImmutableArray.Create(kvp("class"), kvp("style"), kvp("custom")),
-                        defaultAvailableDescriptors,
-                        [divDescriptor, catchAllDescriptor, catchAllDescriptor2]
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("class"), kvp("style")),
-                        defaultAvailableDescriptors,
-                        [inputDescriptor, catchAllDescriptor]
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("nodashprefixA")),
-                        defaultWildcardDescriptors,
-                        [inputWildcardPrefixDescriptor]
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("nodashprefix-ABC-DEF"), kvp("random")),
-                        defaultWildcardDescriptors,
-                        [inputWildcardPrefixDescriptor]
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("prefixABCnodashprefix")),
-                        defaultWildcardDescriptors,
-                        default
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("prefix-")),
-                        defaultWildcardDescriptors,
-                        default
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("nodashprefix")),
-                        defaultWildcardDescriptors,
-                        default
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("prefix-A")),
-                        defaultWildcardDescriptors,
-                        [catchAllWildcardPrefixDescriptor]
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("prefix-ABC-DEF"), kvp("random")),
-                        defaultWildcardDescriptors,
-                        [catchAllWildcardPrefixDescriptor]
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("prefix-abc"), kvp("nodashprefix-def")),
-                        defaultWildcardDescriptors,
-                        [inputWildcardPrefixDescriptor, catchAllWildcardPrefixDescriptor]
-                    },
-                    {
-                        "input",
-                        ImmutableArray.Create(kvp("class"), kvp("prefix-abc"), kvp("onclick"), kvp("nodashprefix-def"), kvp("style")),
-                        defaultWildcardDescriptors,
-                        [inputWildcardPrefixDescriptor, catchAllWildcardPrefixDescriptor]
-                    },
-                };
+                    "input",
+                    ImmutableArray.Create(kvp("class"), kvp("style")),
+                    defaultAvailableDescriptors,
+                    [inputDescriptor, catchAllDescriptor]
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("nodashprefixA")),
+                    defaultWildcardDescriptors,
+                    [inputWildcardPrefixDescriptor]
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("nodashprefix-ABC-DEF"), kvp("random")),
+                    defaultWildcardDescriptors,
+                    [inputWildcardPrefixDescriptor]
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("prefixABCnodashprefix")),
+                    defaultWildcardDescriptors,
+                    null
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("prefix-")),
+                    defaultWildcardDescriptors,
+                    null
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("nodashprefix")),
+                    defaultWildcardDescriptors,
+                    null
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("prefix-A")),
+                    defaultWildcardDescriptors,
+                    [catchAllWildcardPrefixDescriptor]
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("prefix-ABC-DEF"), kvp("random")),
+                    defaultWildcardDescriptors,
+                    [catchAllWildcardPrefixDescriptor]
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("prefix-abc"), kvp("nodashprefix-def")),
+                    defaultWildcardDescriptors,
+                    [inputWildcardPrefixDescriptor, catchAllWildcardPrefixDescriptor]
+                },
+                {
+                    "input",
+                    ImmutableArray.Create(kvp("class"), kvp("prefix-abc"), kvp("onclick"), kvp("nodashprefix-def"), kvp("style")),
+                    defaultWildcardDescriptors,
+                    [inputWildcardPrefixDescriptor, catchAllWildcardPrefixDescriptor]
+                },
+            };
         }
     }
 
@@ -359,24 +352,24 @@ public static TheoryData RequiredAttributeData
     public void GetBinding_ReturnsBindingResultDescriptorsWithRequiredAttributes(
         string tagName,
         ImmutableArray<KeyValuePair<string, string>> providedAttributes,
-        ImmutableArray<TagHelperDescriptor> availableDescriptors,
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors)
+        TagHelperCollection availableTagHelpers,
+        TagHelperCollection? expectedTagHelpers)
     {
         // Arrange
-        var tagHelperBinder = new TagHelperBinder(null, availableDescriptors);
+        var binder = new TagHelperBinder(null, availableTagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(tagName, providedAttributes, parentTagName: "p", parentIsTagHelper: false);
-        var descriptors = bindingResult?.Descriptors ?? default;
+        var binding = binder.GetBinding(tagName, providedAttributes, parentTagName: "p", parentIsTagHelper: false);
+        var tagHelpers = binding?.TagHelpers;
 
         // Assert
-        if (expectedDescriptors.IsDefault)
+        if (expectedTagHelpers is null)
         {
-            Assert.True(descriptors.IsDefault);
+            Assert.Null(tagHelpers);
         }
         else
         {
-            Assert.Equal<TagHelperDescriptor>(expectedDescriptors, descriptors);
+            Assert.Equal(expectedTagHelpers, tagHelpers);
         }
     }
 
@@ -384,72 +377,75 @@ public void GetBinding_ReturnsBindingResultDescriptorsWithRequiredAttributes(
     public void GetBinding_ReturnsNullBindingResultPrefixAsTagName()
     {
         // Arrange
-        var catchAllDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var catchAllTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName(TagHelperMatchingConventions.ElementCatchAllName))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [catchAllDescriptor];
-        var tagHelperBinder = new TagHelperBinder("th", descriptors);
+        TagHelperCollection tagHelpers = [catchAllTagHelper];
+        var tagHelperBinder = new TagHelperBinder("th", tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = tagHelperBinder.GetBinding(
             tagName: "th",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.Null(bindingResult);
+        Assert.Null(binding);
     }
 
     [Fact]
     public void GetBinding_ReturnsBindingResultCatchAllDescriptorsForPrefixedTags()
     {
         // Arrange
-        var catchAllDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var catchAllTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName(TagHelperMatchingConventions.ElementCatchAllName))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [catchAllDescriptor];
-        var tagHelperBinder = new TagHelperBinder("th:", descriptors);
+        TagHelperCollection tagHelpers = [catchAllTagHelper];
+        var tagHelperBinder = new TagHelperBinder("th:", tagHelpers);
 
         // Act
-        var bindingResultDiv = tagHelperBinder.GetBinding(
+        var bindingDiv = tagHelperBinder.GetBinding(
             tagName: "th:div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
-        var bindingResultSpan = tagHelperBinder.GetBinding(
+        var bindingSpan = tagHelperBinder.GetBinding(
             tagName: "th:span",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        var descriptor = Assert.Single(bindingResultDiv.Descriptors);
-        Assert.Same(catchAllDescriptor, descriptor);
-        descriptor = Assert.Single(bindingResultSpan.Descriptors);
-        Assert.Same(catchAllDescriptor, descriptor);
+        Assert.NotNull(bindingDiv);
+        var tagHelper = Assert.Single(bindingDiv.TagHelpers);
+        Assert.Same(catchAllTagHelper, tagHelper);
+        Assert.NotNull(bindingSpan);
+        tagHelper = Assert.Single(bindingSpan.TagHelpers);
+        Assert.Same(catchAllTagHelper, tagHelper);
     }
 
     [Fact]
     public void GetBinding_ReturnsBindingResultDescriptorsForPrefixedTags()
     {
         // Arrange
-        var divDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor];
-        var tagHelperBinder = new TagHelperBinder("th:", descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper];
+        var tagHelperBinder = new TagHelperBinder("th:", tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = tagHelperBinder.GetBinding(
             tagName: "th:div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        var descriptor = Assert.Single(bindingResult.Descriptors);
-        Assert.Same(divDescriptor, descriptor);
+        Assert.NotNull(binding);
+        var tagHelper = Assert.Single(binding.TagHelpers);
+        Assert.Same(divTagHelper, tagHelper);
     }
 
     [Theory]
@@ -458,114 +454,117 @@ public void GetBinding_ReturnsBindingResultDescriptorsForPrefixedTags()
     public void GetBinding_ReturnsNullForUnprefixedTags(string tagName)
     {
         // Arrange
-        var divDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName(tagName))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor];
-        var tagHelperBinder = new TagHelperBinder("th:", descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper];
+        var binder = new TagHelperBinder("th:", tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.Null(bindingResult);
+        Assert.Null(binding);
     }
 
     [Fact]
     public void GetDescriptors_ReturnsNothingForUnregisteredTags()
     {
         // Arrange
-        var divDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
-        var spanDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo2", "SomeAssembly")
+        var spanTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo2", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("span"))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor, spanDescriptor];
-        var tagHelperBinder = new TagHelperBinder(null, descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper, spanTagHelper];
+        var binder = new TagHelperBinder(null, tagHelpers);
 
         // Act
-        var tagHelperBinding = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "foo",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.Null(tagHelperBinding);
+        Assert.Null(binding);
     }
 
     [Fact]
     public void GetDescriptors_ReturnsCatchAllsWithEveryTagName()
     {
         // Arrange
-        var divDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
-        var spanDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo2", "SomeAssembly")
+        var spanTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo2", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("span"))
             .Build();
-        var catchAllDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo3", "SomeAssembly")
+        var catchAllTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo3", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName(TagHelperMatchingConventions.ElementCatchAllName))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor, spanDescriptor, catchAllDescriptor];
-        var tagHelperBinder = new TagHelperBinder(null, descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper, spanTagHelper, catchAllTagHelper];
+        var binder = new TagHelperBinder(null, tagHelpers);
 
         // Act
-        var divBinding = tagHelperBinder.GetBinding(
+        var divBinding = binder.GetBinding(
             tagName: "div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
-        var spanBinding = tagHelperBinder.GetBinding(
+        var spanBinding = binder.GetBinding(
             tagName: "span",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
         // For divs
-        Assert.Equal(2, divBinding.Descriptors.Count());
-        Assert.Contains(divDescriptor, divBinding.Descriptors);
-        Assert.Contains(catchAllDescriptor, divBinding.Descriptors);
+        Assert.NotNull(divBinding);
+        Assert.Equal(2, divBinding.TagHelpers.Count);
+        Assert.Contains(divTagHelper, divBinding.TagHelpers);
+        Assert.Contains(catchAllTagHelper, divBinding.TagHelpers);
 
         // For spans
-        Assert.Equal(2, spanBinding.Descriptors.Count());
-        Assert.Contains(spanDescriptor, spanBinding.Descriptors);
-        Assert.Contains(catchAllDescriptor, spanBinding.Descriptors);
+        Assert.NotNull(spanBinding);
+        Assert.Equal(2, spanBinding.TagHelpers.Count);
+        Assert.Contains(spanTagHelper, spanBinding.TagHelpers);
+        Assert.Contains(catchAllTagHelper, spanBinding.TagHelpers);
     }
 
     [Fact]
     public void GetDescriptors_DuplicateDescriptorsAreNotPartOfTagHelperDescriptorPool()
     {
         // Arrange
-        var divDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor, divDescriptor];
-        var tagHelperBinder = new TagHelperBinder(null, descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper, divTagHelper];
+        var binder = new TagHelperBinder(null, tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        var descriptor = Assert.Single(bindingResult.Descriptors);
-        Assert.Same(divDescriptor, descriptor);
+        Assert.NotNull(binding);
+        var tagHelper = Assert.Single(binding.TagHelpers);
+        Assert.Same(divTagHelper, tagHelper);
     }
 
     [Fact]
     public void GetBinding_DescriptorWithMultipleRules_CorrectlySelectsMatchingRules()
     {
         // Arrange
-        var multiRuleDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo", "SomeAssembly")
+        var multiRuleTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule
                 .RequireTagName(TagHelperMatchingConventions.ElementCatchAllName)
                 .RequireParentTag("body"))
@@ -574,20 +573,21 @@ public void GetBinding_DescriptorWithMultipleRules_CorrectlySelectsMatchingRules
             .TagMatchingRuleDescriptor(rule => rule
                 .RequireTagName("span"))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [multiRuleDescriptor];
-        var tagHelperBinder = new TagHelperBinder(null, descriptors);
+        TagHelperCollection tagHelper = [multiRuleTagHelper];
+        var binder = new TagHelperBinder(null, tagHelper);
 
         // Act
-        var binding = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        var boundDescriptor = Assert.Single(binding.Descriptors);
-        Assert.Same(multiRuleDescriptor, boundDescriptor);
-        var boundRules = binding.GetBoundRules(boundDescriptor);
+        Assert.NotNull(binding);
+        var boundTagHelper = Assert.Single(binding.TagHelpers);
+        Assert.Same(multiRuleTagHelper, boundTagHelper);
+        var boundRules = binding.GetBoundRules(boundTagHelper);
         var boundRule = Assert.Single(boundRules);
         Assert.Equal("div", boundRule.TagName);
     }
@@ -596,26 +596,27 @@ public void GetBinding_DescriptorWithMultipleRules_CorrectlySelectsMatchingRules
     public void GetBinding_PrefixedParent_ReturnsBinding()
     {
         // Arrange
-        var divDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div").RequireParentTag("p"))
             .Build();
-        var pDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo2", "SomeAssembly")
+        var pTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo2", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("p"))
             .Build();
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor, pDescriptor];
-        var tagHelperBinder = new TagHelperBinder("th:", descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper, pTagHelper];
+        var binder = new TagHelperBinder("th:", tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "th:div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "th:p",
             parentIsTagHelper: true);
 
         // Assert
-        var boundDescriptor = Assert.Single(bindingResult.Descriptors);
-        Assert.Same(divDescriptor, boundDescriptor);
-        var boundRules = bindingResult.GetBoundRules(boundDescriptor);
+        Assert.NotNull(binding);
+        var boundTagHelper = Assert.Single(binding.TagHelpers);
+        Assert.Same(divTagHelper, boundTagHelper);
+        var boundRules = binding.GetBoundRules(boundTagHelper);
         var boundRule = Assert.Single(boundRules);
         Assert.Equal("div", boundRule.TagName);
         Assert.Equal("p", boundRule.ParentTag);
@@ -625,78 +626,81 @@ public void GetBinding_PrefixedParent_ReturnsBinding()
     public void GetBinding_IsAttributeMatch_SingleAttributeMatch()
     {
         // Arrange
-        var divDescriptor = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .ClassifyAttributesOnly(true)
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
 
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor];
-        var tagHelperBinder = new TagHelperBinder("", descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper];
+        var binder = new TagHelperBinder("", tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.True(bindingResult.IsAttributeMatch);
+        Assert.NotNull(binding);
+        Assert.True(binding.IsAttributeMatch);
     }
 
     [Fact]
     public void GetBinding_IsAttributeMatch_MultipleAttributeMatches()
     {
         // Arrange
-        var divDescriptor1 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper1 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .ClassifyAttributesOnly(true)
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
 
-        var divDescriptor2 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper2 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .ClassifyAttributesOnly(true)
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
 
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor1, divDescriptor2];
-        var tagHelperBinder = new TagHelperBinder("", descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper1, divTagHelper2];
+        var binder = new TagHelperBinder("", tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.True(bindingResult.IsAttributeMatch);
+        Assert.NotNull(binding);
+        Assert.True(binding.IsAttributeMatch);
     }
 
     [Fact]
     public void GetBinding_IsAttributeMatch_MixedAttributeMatches()
     {
         // Arrange
-        var divDescriptor1 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper1 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .ClassifyAttributesOnly(true)
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
 
-        var divDescriptor2 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
+        var divTagHelper2 = TagHelperDescriptorBuilder.CreateTagHelper("foo1", "SomeAssembly")
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .Build();
 
-        ImmutableArray<TagHelperDescriptor> descriptors = [divDescriptor1, divDescriptor2];
-        var tagHelperBinder = new TagHelperBinder("", descriptors);
+        TagHelperCollection tagHelpers = [divTagHelper1, divTagHelper2];
+        var tagHelperBinder = new TagHelperBinder("", tagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = tagHelperBinder.GetBinding(
             tagName: "div",
-            attributes: ImmutableArray<KeyValuePair<string, string>>.Empty,
+            attributes: [],
             parentTagName: "p",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.False(bindingResult.IsAttributeMatch);
+        Assert.NotNull(binding);
+        Assert.False(binding.IsAttributeMatch);
     }
 
     [Fact]
@@ -707,20 +711,20 @@ public void GetBinding_CaseSensitiveRule_CaseMismatch_ReturnsNull()
             .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
             .SetCaseSensitive()
             .Build();
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors = [divTagHelper];
+        TagHelperCollection expectedTagHelpers = [divTagHelper];
         var expectedAttributes = ImmutableArray.Create(
             new KeyValuePair<string, string>("class", "something"));
-        var tagHelperBinder = new TagHelperBinder("th:", expectedDescriptors);
+        var binder = new TagHelperBinder("th:", expectedTagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "th:Div",
             attributes: expectedAttributes,
             parentTagName: "body",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.Null(bindingResult);
+        Assert.Null(binding);
     }
 
     [Fact]
@@ -733,19 +737,19 @@ public void GetBinding_CaseSensitiveRequiredAttribute_CaseMismatch_ReturnsNull()
                 .RequireAttributeDescriptor(attribute => attribute.Name("class")))
             .SetCaseSensitive()
             .Build();
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors = [divTagHelper];
+        TagHelperCollection expectedTagHelpers = [divTagHelper];
         var expectedAttributes = ImmutableArray.Create(
             new KeyValuePair<string, string>("CLASS", "something"));
-        var tagHelperBinder = new TagHelperBinder(null, expectedDescriptors);
+        var binder = new TagHelperBinder(null, expectedTagHelpers);
 
         // Act
-        var bindingResult = tagHelperBinder.GetBinding(
+        var binding = binder.GetBinding(
             tagName: "div",
             attributes: expectedAttributes,
             parentTagName: "body",
             parentIsTagHelper: false);
 
         // Assert
-        Assert.Null(bindingResult);
+        Assert.Null(binding);
     }
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/CompilationTagHelperFeature.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/CompilationTagHelperFeature.cs
index 9e52ee57431..40f8909b4d3 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/CompilationTagHelperFeature.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/CompilationTagHelperFeature.cs
@@ -15,7 +15,7 @@ public sealed class CompilationTagHelperFeature : RazorEngineFeatureBase, ITagHe
     private ImmutableArray<ITagHelperDescriptorProvider> _providers;
     private IMetadataReferenceFeature? _referenceFeature;
 
-    public IReadOnlyList<TagHelperDescriptor> GetDescriptors(CancellationToken cancellationToken = default)
+    public TagHelperCollection GetTagHelpers(CancellationToken cancellationToken = default)
     {
         var compilation = CSharpCompilation.Create("__TagHelpers", references: _referenceFeature?.References);
         if (!IsValidCompilation(compilation))
@@ -23,15 +23,15 @@ public IReadOnlyList<TagHelperDescriptor> GetDescriptors(CancellationToken cance
             return [];
         }
 
-        var results = new List<TagHelperDescriptor>();
-        var context = new TagHelperDescriptorProviderContext(compilation, results);
+        using var builder = new TagHelperCollection.Builder();
+        var context = new TagHelperDescriptorProviderContext(compilation, builder);
 
         foreach (var provider in _providers)
         {
             provider.Execute(context, cancellationToken);
         }
 
-        return results;
+        return builder.ToCollection();
     }
 
     protected override void OnInitialized()
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorIntermediateNodeLoweringPhase.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorIntermediateNodeLoweringPhase.cs
index 8f100de820f..24a45e86fd1 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorIntermediateNodeLoweringPhase.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorIntermediateNodeLoweringPhase.cs
@@ -1035,7 +1035,7 @@ public override void VisitMarkupTagHelperElement(MarkupTagHelperElementSyntax no
                 TagName = tagName,
                 TagMode = info.TagMode,
                 Source = BuildSourceSpanFromNode(node),
-                TagHelpers = info.BindingResult.Descriptors
+                TagHelpers = info.BindingResult.TagHelpers
             };
 
             _builder.Push(tagHelperNode);
@@ -1080,11 +1080,11 @@ public override void VisitMarkupMinimizedTagHelperAttribute(MarkupMinimizedTagHe
             }
 
             var element = node.FirstAncestorOrSelf<MarkupTagHelperElementSyntax>();
-            var descriptors = element.TagHelperInfo.BindingResult.Descriptors;
+            var tagHelpers = element.TagHelperInfo.BindingResult.TagHelpers;
             var attributeName = node.Name.GetContent();
 
             using var matches = new PooledArrayBuilder<TagHelperAttributeMatch>();
-            TagHelperMatchingConventions.GetAttributeMatches(descriptors, attributeName, ref matches.AsRef());
+            TagHelperMatchingConventions.GetAttributeMatches(tagHelpers, attributeName, ref matches.AsRef());
 
             if (matches.Any() && _renderedBoundAttributeNames.Add(attributeName))
             {
@@ -1121,12 +1121,12 @@ public override void VisitMarkupMinimizedTagHelperAttribute(MarkupMinimizedTagHe
         public override void VisitMarkupTagHelperAttribute(MarkupTagHelperAttributeSyntax node)
         {
             var element = node.FirstAncestorOrSelf<MarkupTagHelperElementSyntax>();
-            var descriptors = element.TagHelperInfo.BindingResult.Descriptors;
+            var tagHelpers = element.TagHelperInfo.BindingResult.TagHelpers;
             var attributeName = node.Name.GetContent();
             var attributeValueNode = node.Value;
 
             using var matches = new PooledArrayBuilder<TagHelperAttributeMatch>();
-            TagHelperMatchingConventions.GetAttributeMatches(descriptors, attributeName, ref matches.AsRef());
+            TagHelperMatchingConventions.GetAttributeMatches(tagHelpers, attributeName, ref matches.AsRef());
 
             if (matches.Any() && _renderedBoundAttributeNames.Add(attributeName))
             {
@@ -1753,7 +1753,7 @@ public override void VisitMarkupTagHelperElement(MarkupTagHelperElementSyntax no
                 TagName = tagName,
                 TagMode = info.TagMode,
                 Source = BuildSourceSpanFromNode(node),
-                TagHelpers = info.BindingResult.Descriptors,
+                TagHelpers = info.BindingResult.TagHelpers,
                 StartTagSpan = node.StartTag.Name.GetSourceSpan(SourceDocument)
             };
 
@@ -1828,11 +1828,11 @@ public override void VisitMarkupMinimizedTagHelperAttribute(MarkupMinimizedTagHe
             }
 
             var element = node.FirstAncestorOrSelf<MarkupTagHelperElementSyntax>();
-            var descriptors = element.TagHelperInfo.BindingResult.Descriptors;
+            var tagHelpers = element.TagHelperInfo.BindingResult.TagHelpers;
             var attributeName = node.Name.GetContent();
 
             using var matches = new PooledArrayBuilder<TagHelperAttributeMatch>();
-            TagHelperMatchingConventions.GetAttributeMatches(descriptors, attributeName, ref matches.AsRef());
+            TagHelperMatchingConventions.GetAttributeMatches(tagHelpers, attributeName, ref matches.AsRef());
 
             if (matches.Any() && _renderedBoundAttributeNames.Add(attributeName))
             {
@@ -1877,11 +1877,11 @@ public override void VisitMarkupMinimizedTagHelperDirectiveAttribute(MarkupMinim
             }
 
             var element = node.FirstAncestorOrSelf<MarkupTagHelperElementSyntax>();
-            var descriptors = element.TagHelperInfo.BindingResult.Descriptors;
+            var tagHelpers = element.TagHelperInfo.BindingResult.TagHelpers;
             var attributeName = node.FullName;
 
             using var matches = new PooledArrayBuilder<TagHelperAttributeMatch>();
-            TagHelperMatchingConventions.GetAttributeMatches(descriptors, attributeName, ref matches.AsRef());
+            TagHelperMatchingConventions.GetAttributeMatches(tagHelpers, attributeName, ref matches.AsRef());
 
             if (matches.Any() && _renderedBoundAttributeNames.Add(attributeName))
             {
@@ -1930,12 +1930,12 @@ public override void VisitMarkupMinimizedTagHelperDirectiveAttribute(MarkupMinim
         public override void VisitMarkupTagHelperAttribute(MarkupTagHelperAttributeSyntax node)
         {
             var element = node.FirstAncestorOrSelf<MarkupTagHelperElementSyntax>();
-            var descriptors = element.TagHelperInfo.BindingResult.Descriptors;
+            var tagHelpers = element.TagHelperInfo.BindingResult.TagHelpers;
             var attributeName = node.Name.GetContent();
             var attributeValueNode = node.Value;
 
             using var matches = new PooledArrayBuilder<TagHelperAttributeMatch>();
-            TagHelperMatchingConventions.GetAttributeMatches(descriptors, attributeName, ref matches.AsRef());
+            TagHelperMatchingConventions.GetAttributeMatches(tagHelpers, attributeName, ref matches.AsRef());
 
             if (matches.Any() && _renderedBoundAttributeNames.Add(attributeName))
             {
@@ -1971,12 +1971,12 @@ public override void VisitMarkupTagHelperAttribute(MarkupTagHelperAttributeSynta
         public override void VisitMarkupTagHelperDirectiveAttribute(MarkupTagHelperDirectiveAttributeSyntax node)
         {
             var element = node.FirstAncestorOrSelf<MarkupTagHelperElementSyntax>();
-            var descriptors = element.TagHelperInfo.BindingResult.Descriptors;
+            var tagHelpers = element.TagHelperInfo.BindingResult.TagHelpers;
             var attributeName = node.FullName;
             var attributeValueNode = node.Value;
 
             using var matches = new PooledArrayBuilder<TagHelperAttributeMatch>();
-            TagHelperMatchingConventions.GetAttributeMatches(descriptors, attributeName, ref matches.AsRef());
+            TagHelperMatchingConventions.GetAttributeMatches(tagHelpers, attributeName, ref matches.AsRef());
 
             if (matches.Any() && _renderedBoundAttributeNames.Add(attributeName))
             {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase.cs
index 2e4ad2a7365..7b0ac035e2b 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase.cs
@@ -3,10 +3,8 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Threading;
 using Microsoft.AspNetCore.Razor.Language.Components;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
@@ -30,7 +28,7 @@ protected override void ExecuteCore(RazorCodeDocument codeDocument, Cancellation
                 return;
             }
 
-            tagHelpers = tagHelperFeature.GetDescriptors(cancellationToken);
+            tagHelpers = tagHelperFeature.GetTagHelpers(cancellationToken);
         }
 
         using var _ = GetPooledVisitor(codeDocument, tagHelpers, cancellationToken, out var visitor);
@@ -79,7 +77,9 @@ internal abstract class DirectiveVisitor : SyntaxWalker, IPoolableObject
         private RazorSourceDocument? _source;
         private CancellationToken _cancellationToken;
 
-        private readonly HashSet<TagHelperDescriptor> _matches = [];
+        private TagHelperCollection.Builder? _matches;
+
+        private TagHelperCollection.Builder Matches => _matches ??= [];
 
         protected bool IsInitialized => _isInitialized;
         protected RazorSourceDocument Source => _source.AssumeNotNull();
@@ -100,7 +100,7 @@ public void Visit(RazorSyntaxTree tree)
             Visit(tree.Root);
         }
 
-        public ImmutableArray<TagHelperDescriptor> GetResults() => [.. _matches];
+        public TagHelperCollection GetResults() => _matches?.ToCollection() ?? [];
 
         protected void Initialize(string? filePath, CancellationToken cancellationToken)
         {
@@ -111,7 +111,12 @@ protected void Initialize(string? filePath, CancellationToken cancellationToken)
 
         public virtual void Reset()
         {
-            _matches.Clear();
+            if (_matches is { } matches)
+            {
+                matches.Dispose();
+                _matches = null;
+            }
+
             _filePath = null;
             _source = null;
             _cancellationToken = default;
@@ -121,7 +126,7 @@ public virtual void Reset()
         protected void AddMatch(TagHelperDescriptor tagHelper)
         {
             _cancellationToken.ThrowIfCancellationRequested();
-            _matches.Add(tagHelper);
+            Matches.Add(tagHelper);
         }
 
         protected void AddMatches(List<TagHelperDescriptor> tagHelpers)
@@ -130,14 +135,14 @@ protected void AddMatches(List<TagHelperDescriptor> tagHelpers)
 
             foreach (var tagHelper in tagHelpers)
             {
-                _matches.Add(tagHelper);
+                Matches.Add(tagHelper);
             }
         }
 
         protected void RemoveMatch(TagHelperDescriptor tagHelper)
         {
             _cancellationToken.ThrowIfCancellationRequested();
-            _matches.Remove(tagHelper);
+            Matches.Remove(tagHelper);
         }
 
         protected void RemoveMatches(List<TagHelperDescriptor> tagHelpers)
@@ -146,7 +151,7 @@ protected void RemoveMatches(List<TagHelperDescriptor> tagHelpers)
 
             foreach (var tagHelper in tagHelpers)
             {
-                _matches.Remove(tagHelper);
+                Matches.Remove(tagHelper);
             }
         }
 
@@ -180,7 +185,7 @@ internal sealed class TagHelperDirectiveVisitor : DirectiveVisitor
         /// </summary>
         private readonly Dictionary<string, List<TagHelperDescriptor>> _tagHelperMap = new(StringComparer.Ordinal);
 
-        private IReadOnlyList<TagHelperDescriptor>? _descriptors;
+        private TagHelperCollection? _tagHelpers;
         private bool _tagHelperMapComputed;
         private string? _tagHelperPrefix;
 
@@ -201,13 +206,13 @@ private Dictionary<string, List<TagHelperDescriptor>> TagHelperMap
 
                 void ComputeTagHelperMap()
                 {
-                    var tagHelpers = _descriptors.AssumeNotNull();
+                    var tagHelpers = _tagHelpers.AssumeNotNull();
 
                     string? currentAssemblyName = null;
                     List<TagHelperDescriptor>? currentTagHelpers = null;
 
                     // We don't want to consider components in a view document.
-                    foreach (var tagHelper in tagHelpers.AsEnumerable())
+                    foreach (var tagHelper in tagHelpers)
                     {
                         if (!tagHelper.IsAnyComponentDocumentTagHelper())
                         {
@@ -230,13 +235,13 @@ void ComputeTagHelperMap()
         }
 
         public void Initialize(
-            IReadOnlyList<TagHelperDescriptor> descriptors,
+            TagHelperCollection tagHelpers,
             string? filePath,
             CancellationToken cancellationToken = default)
         {
             Debug.Assert(!IsInitialized);
 
-            _descriptors = descriptors;
+            _tagHelpers = tagHelpers;
 
             base.Initialize(filePath, cancellationToken);
         }
@@ -250,7 +255,7 @@ public override void Reset()
 
             _tagHelperMap.Clear();
             _tagHelperMapComputed = false;
-            _descriptors = null;
+            _tagHelpers = null;
             _tagHelperPrefix = null;
 
             base.Reset();
@@ -381,14 +386,14 @@ internal sealed class ComponentDirectiveVisitor : DirectiveVisitor
         private List<TagHelperDescriptor>? _componentsWithoutNamespace;
 
         public void Initialize(
-            IReadOnlyList<TagHelperDescriptor> descriptors,
+            TagHelperCollection tagHelpers,
             string? filePath,
             string? currentNamespace,
             CancellationToken cancellationToken = default)
         {
             Debug.Assert(!IsInitialized);
 
-            foreach (var component in descriptors.AsEnumerable())
+            foreach (var component in tagHelpers)
             {
                 cancellationToken.ThrowIfCancellationRequested();
 
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase_Pooling.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase_Pooling.cs
index 1107139723e..83eff11bdec 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase_Pooling.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperContextDiscoveryPhase_Pooling.cs
@@ -30,7 +30,7 @@ public void Dispose()
 
     internal static PooledDirectiveVisitor GetPooledVisitor(
         RazorCodeDocument codeDocument,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers,
+        TagHelperCollection tagHelpers,
         CancellationToken cancellationToken,
         out DirectiveVisitor visitor)
     {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperRewritePhase.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperRewritePhase.cs
index f0e3b7277a1..0b959abc1c7 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperRewritePhase.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DefaultRazorTagHelperRewritePhase.cs
@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Threading;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
 
@@ -18,15 +16,15 @@ protected override void ExecuteCore(RazorCodeDocument codeDocument, Cancellation
         {
             // No descriptors, so no need to see if any are used. Without setting this though,
             // we trigger an Assert in the ProcessRemaining method in the source generator.
-            codeDocument.SetReferencedTagHelpers(ImmutableHashSet<TagHelperDescriptor>.Empty);
+            codeDocument.SetReferencedTagHelpers([]);
             return;
         }
 
         var binder = context.GetBinder();
-        var usedHelpers = new HashSet<TagHelperDescriptor>();
+        using var usedHelpers = new TagHelperCollection.Builder();
         var rewrittenSyntaxTree = TagHelperParseTreeRewriter.Rewrite(syntaxTree, binder, usedHelpers, cancellationToken);
 
-        codeDocument.SetReferencedTagHelpers(usedHelpers);
+        codeDocument.SetReferencedTagHelpers(usedHelpers.ToCollection());
         codeDocument.SetSyntaxTree(rewrittenSyntaxTree);
     }
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/ITagHelperFeature.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/ITagHelperFeature.cs
index d69f3fcf62c..2d4bdc9abc8 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/ITagHelperFeature.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/ITagHelperFeature.cs
@@ -1,12 +1,11 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Generic;
 using System.Threading;
 
 namespace Microsoft.AspNetCore.Razor.Language;
 
 public interface ITagHelperFeature : IRazorEngineFeature
 {
-    IReadOnlyList<TagHelperDescriptor> GetDescriptors(CancellationToken cancellationToken = default);
+    TagHelperCollection GetTagHelpers(CancellationToken cancellationToken = default);
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Intermediate/TagHelperIntermediateNode.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Intermediate/TagHelperIntermediateNode.cs
index ce69f80f4ed..393833562b9 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Intermediate/TagHelperIntermediateNode.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Intermediate/TagHelperIntermediateNode.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using System.Linq;
 
 namespace Microsoft.AspNetCore.Razor.Language.Intermediate;
@@ -16,7 +15,7 @@ public sealed class TagHelperIntermediateNode : IntermediateNode
     /// </summary>
     public SourceSpan? StartTagSpan { get; init; }
 
-    public ImmutableArray<TagHelperDescriptor> TagHelpers { get; init => field = value.NullToEmpty(); } = [];
+    public TagHelperCollection TagHelpers { get; init => field = value ?? []; } = [];
 
     public override IntermediateNodeCollection Children { get => field ??= []; }
 
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperBlockRewriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperBlockRewriter.cs
index 1b69b0860bc..fde22e52249 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperBlockRewriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperBlockRewriter.cs
@@ -61,7 +61,7 @@ public static MarkupTagHelperStartTagSyntax Rewrite(
         string tagName,
         RazorParserOptions options,
         MarkupStartTagSyntax startTag,
-        TagHelperBinding bindingResult,
+        TagHelperBinding binding,
         ErrorSink errorSink,
         RazorSourceDocument source)
     {
@@ -83,7 +83,7 @@ public static MarkupTagHelperStartTagSyntax Rewrite(
                 result = TryParseAttribute(
                     tagName,
                     attributeBlock,
-                    bindingResult.Descriptors,
+                    binding.TagHelpers,
                     errorSink,
                     processedBoundAttributeNames,
                     options);
@@ -96,7 +96,7 @@ public static MarkupTagHelperStartTagSyntax Rewrite(
                 result = TryParseMinimizedAttribute(
                     tagName,
                     minimizedAttributeBlock,
-                    bindingResult.Descriptors,
+                    binding.TagHelpers,
                     errorSink,
                     processedBoundAttributeNames);
                 attributeBuilder.Add(result.RewrittenAttribute);
@@ -181,7 +181,7 @@ public static MarkupTagHelperStartTagSyntax Rewrite(
                  string.IsNullOrWhiteSpace(GetAttributeValueContent(result.RewrittenAttribute))))
             {
                 var errorLocation = new SourceSpan(attributeNameLocation, result.AttributeName.Length);
-                var propertyTypeName = GetPropertyType(result.AttributeName, bindingResult.Descriptors);
+                var propertyTypeName = GetPropertyType(result.AttributeName, binding.TagHelpers);
                 var diagnostic = RazorDiagnosticFactory.CreateTagHelper_EmptyBoundAttribute(errorLocation, result.AttributeName, tagName, propertyTypeName);
                 errorSink.OnError(diagnostic);
             }
@@ -216,12 +216,12 @@ public static MarkupTagHelperStartTagSyntax Rewrite(
     private static TryParseResult TryParseMinimizedAttribute(
         string tagName,
         MarkupMinimizedAttributeBlockSyntax attributeBlock,
-        IEnumerable<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         ErrorSink errorSink,
         HashSet<string> processedBoundAttributeNames)
     {
         // Have a name now. Able to determine correct isBoundNonStringAttribute value.
-        var result = CreateTryParseResult(attributeBlock.Name.GetContent(), descriptors, processedBoundAttributeNames);
+        var result = CreateTryParseResult(attributeBlock.Name.GetContent(), tagHelpers, processedBoundAttributeNames);
 
         result.AttributeStructure = AttributeStructure.Minimized;
 
@@ -253,13 +253,13 @@ private static TryParseResult TryParseMinimizedAttribute(
     private static TryParseResult TryParseAttribute(
         string tagName,
         MarkupAttributeBlockSyntax attributeBlock,
-        IEnumerable<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         ErrorSink errorSink,
         HashSet<string> processedBoundAttributeNames,
         RazorParserOptions options)
     {
         // Have a name now. Able to determine correct isBoundNonStringAttribute value.
-        var result = CreateTryParseResult(attributeBlock.Name.GetContent(), descriptors, processedBoundAttributeNames);
+        var result = CreateTryParseResult(attributeBlock.Name.GetContent(), tagHelpers, processedBoundAttributeNames);
 
         if (attributeBlock.ValuePrefix == null)
         {
@@ -465,11 +465,11 @@ private static MarkupTagHelperAttributeValueSyntax RewriteAttributeValue(TryPars
     }
 
     // Determines the full name of the Type of the property corresponding to an attribute with the given name.
-    private static string GetPropertyType(string name, IEnumerable<TagHelperDescriptor> descriptors)
+    private static string GetPropertyType(string name, TagHelperCollection tagHelpers)
     {
-        foreach (var descriptor in descriptors)
+        foreach (var tagHelper in tagHelpers)
         {
-            if (TagHelperMatchingConventions.TryGetFirstBoundAttributeMatch(descriptor, name, out var match))
+            if (TagHelperMatchingConventions.TryGetFirstBoundAttributeMatch(tagHelper, name, out var match))
             {
                 return match.IsIndexerMatch
                     ? match.Attribute.IndexerTypeName
@@ -483,7 +483,7 @@ private static string GetPropertyType(string name, IEnumerable<TagHelperDescript
     // Create a TryParseResult for given name, filling in binding details.
     private static TryParseResult CreateTryParseResult(
         string name,
-        IEnumerable<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         HashSet<string> processedBoundAttributeNames)
     {
         var isBoundAttribute = false;
@@ -493,9 +493,9 @@ private static TryParseResult CreateTryParseResult(
         var isDirectiveAttribute = false;
         var isDuplicateAttribute = false;
 
-        foreach (var descriptor in descriptors)
+        foreach (var tagHelper in tagHelpers)
         {
-            if (TagHelperMatchingConventions.TryGetFirstBoundAttributeMatch(descriptor, name, out var match))
+            if (TagHelperMatchingConventions.TryGetFirstBoundAttributeMatch(tagHelper, name, out var match))
             {
                 isBoundAttribute = true;
                 isBoundNonStringAttribute = !match.ExpectsStringValue;
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperParseTreeRewriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperParseTreeRewriter.cs
index 26dc3dae791..7706ba59913 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperParseTreeRewriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperParseTreeRewriter.cs
@@ -18,7 +18,7 @@ internal static class TagHelperParseTreeRewriter
     public static RazorSyntaxTree Rewrite(
         RazorSyntaxTree syntaxTree,
         TagHelperBinder binder,
-        ISet<TagHelperDescriptor>? usedDescriptors = null,
+        TagHelperCollection.Builder? usedDescriptors = null,
         CancellationToken cancellationToken = default)
     {
         using var errorSink = new ErrorSink();
@@ -41,7 +41,7 @@ public static RazorSyntaxTree Rewrite(
         builder.AddRange(treeDiagnostics);
         builder.AddRange(sinkDiagnostics);
 
-        foreach (var descriptor in binder.Descriptors)
+        foreach (var descriptor in binder.TagHelpers)
         {
             descriptor.AppendAllDiagnostics(ref builder.AsRef());
         }
@@ -57,7 +57,7 @@ internal sealed class Rewriter(
         TagHelperBinder binder,
         RazorParserOptions options,
         ErrorSink errorSink,
-        ISet<TagHelperDescriptor>? usedDescriptors,
+        TagHelperCollection.Builder? usedDescriptors,
         CancellationToken cancellationToken) : SyntaxRewriter
     {
         // Internal for testing.
@@ -69,7 +69,7 @@ internal sealed class Rewriter(
         private readonly Stack<TagTracker> _trackerStack = new();
         private readonly ErrorSink _errorSink = errorSink;
         private readonly RazorParserOptions _options = options;
-        private readonly ISet<TagHelperDescriptor> _usedDescriptors = usedDescriptors ?? new HashSet<TagHelperDescriptor>();
+        private readonly TagHelperCollection.Builder? _usedDescriptors = usedDescriptors;
         private readonly CancellationToken _cancellationToken = cancellationToken;
 
         private TagTracker? CurrentTracker => _trackerStack.Count > 0 ? _trackerStack.Peek() : null;
@@ -282,10 +282,7 @@ private bool TryRewriteTagHelperStart(
                 return false;
             }
 
-            foreach (var descriptor in tagHelperBinding.Descriptors)
-            {
-                _usedDescriptors.Add(descriptor);
-            }
+            _usedDescriptors?.AddRange(tagHelperBinding.TagHelpers);
 
             ValidateParentAllowsTagHelper(tagName, startTag);
             ValidateBinding(tagHelperBinding, tagName, startTag);
@@ -774,7 +771,7 @@ public bool AllowsChild(string tagName, bool nameIncludesPrefix)
 
                 using var result = new PooledArrayBuilder<string>();
 
-                foreach (var tagHelper in _binding.Descriptors)
+                foreach (var tagHelper in _binding.TagHelpers)
                 {
                     foreach (var allowedChildTag in tagHelper.AllowedChildTags)
                     {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperSpanInternal.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperSpanInternal.cs
index 67737ae0700..df90720bfc8 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperSpanInternal.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Legacy/TagHelperSpanInternal.cs
@@ -1,11 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
-
 namespace Microsoft.AspNetCore.Razor.Language.Legacy;
 
 internal readonly record struct TagHelperSpanInternal(SourceSpan Span, TagHelperBinding Binding)
 {
-    public ImmutableArray<TagHelperDescriptor> TagHelpers => Binding.Descriptors;
+    public TagHelperCollection TagHelpers => Binding.TagHelpers;
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.PropertyTable.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.PropertyTable.cs
index c8f829e5f98..f613688d0a3 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.PropertyTable.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.PropertyTable.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
@@ -25,8 +24,8 @@ private readonly struct PropertyTable()
 
         private readonly object?[] _values = new object?[Size];
 
-        public Property<IReadOnlyList<TagHelperDescriptor>> TagHelpers => new(_values, 0);
-        public Property<ISet<TagHelperDescriptor>> ReferencedTagHelpers => new(_values, 1);
+        public Property<TagHelperCollection> TagHelpers => new(_values, 0);
+        public Property<TagHelperCollection> ReferencedTagHelpers => new(_values, 1);
         public Property<RazorSyntaxTree> PreTagHelperSyntaxTree => new(_values, 2);
         public Property<RazorSyntaxTree> SyntaxTree => new(_values, 3);
         public BoxedProperty<ImmutableArray<RazorSyntaxTree>> ImportSyntaxTrees => new(_values, 4);
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.cs
index b48baabb2c2..ab668c4d145 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorCodeDocument.cs
@@ -63,28 +63,28 @@ public static RazorCodeDocument Create(
         return new RazorCodeDocument(source, imports, parserOptions, codeGenerationOptions);
     }
 
-    internal bool TryGetTagHelpers([NotNullWhen(true)] out IReadOnlyList<TagHelperDescriptor>? result)
+    internal bool TryGetTagHelpers([NotNullWhen(true)] out TagHelperCollection? result)
         => _properties.TagHelpers.TryGetValue(out result);
 
-    internal IReadOnlyList<TagHelperDescriptor>? GetTagHelpers()
+    internal TagHelperCollection? GetTagHelpers()
         => _properties.TagHelpers.Value;
 
-    internal IReadOnlyList<TagHelperDescriptor> GetRequiredTagHelpers()
+    internal TagHelperCollection GetRequiredTagHelpers()
         => _properties.TagHelpers.RequiredValue;
 
-    internal void SetTagHelpers(IReadOnlyList<TagHelperDescriptor>? value)
+    internal void SetTagHelpers(TagHelperCollection? value)
         => _properties.TagHelpers.SetValue(value);
 
-    internal bool TryGetReferencedTagHelpers([NotNullWhen(true)] out ISet<TagHelperDescriptor>? result)
+    internal bool TryGetReferencedTagHelpers([NotNullWhen(true)] out TagHelperCollection? result)
         => _properties.ReferencedTagHelpers.TryGetValue(out result);
 
-    internal ISet<TagHelperDescriptor>? GetReferencedTagHelpers()
+    internal TagHelperCollection? GetReferencedTagHelpers()
         => _properties.ReferencedTagHelpers.Value;
 
-    internal ISet<TagHelperDescriptor> GetRequiredReferencedTagHelpers()
+    internal TagHelperCollection GetRequiredReferencedTagHelpers()
         => _properties.ReferencedTagHelpers.RequiredValue;
 
-    internal void SetReferencedTagHelpers(ISet<TagHelperDescriptor> value)
+    internal void SetReferencedTagHelpers(TagHelperCollection value)
     {
         ArgHelper.ThrowIfNull(value);
         _properties.ReferencedTagHelpers.SetValue(value);
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngine.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngine.cs
index 702782fd46b..e755e4e8317 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngine.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngine.cs
@@ -71,7 +71,7 @@ public RazorCodeDocument Process(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers,
+        TagHelperCollection? tagHelpers,
         CancellationToken cancellationToken = default)
     {
         ArgHelper.ThrowIfNull(source);
@@ -99,7 +99,7 @@ public RazorCodeDocument ProcessDeclarationOnly(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers,
+        TagHelperCollection? tagHelpers,
         CancellationToken cancellationToken = default)
     {
         ArgHelper.ThrowIfNull(source);
@@ -127,7 +127,7 @@ public RazorCodeDocument ProcessDesignTime(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers,
+        TagHelperCollection? tagHelpers,
         CancellationToken cancellationToken = default)
     {
         ArgHelper.ThrowIfNull(source);
@@ -151,7 +151,7 @@ internal RazorCodeDocument CreateCodeDocument(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers,
+        TagHelperCollection? tagHelpers,
         string? cssScope)
     {
         ArgHelper.ThrowIfNull(source);
@@ -163,7 +163,7 @@ internal RazorCodeDocument CreateDesignTimeCodeDocument(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers)
+        TagHelperCollection? tagHelpers)
     {
         ArgHelper.ThrowIfNull(source);
 
@@ -186,7 +186,7 @@ private RazorCodeDocument CreateCodeDocumentCore(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers,
+        TagHelperCollection? tagHelpers,
         string? cssScope,
         Action<RazorParserOptions.Builder>? configureParser,
         Action<RazorCodeGenerationOptions.Builder>? configureCodeGeneration)
@@ -216,7 +216,7 @@ private RazorCodeDocument CreateCodeDocumentDesignTimeCore(
         RazorSourceDocument sourceDocument,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers,
+        TagHelperCollection? tagHelpers,
         Action<RazorParserOptions.Builder>? configureParser,
         Action<RazorCodeGenerationOptions.Builder>? configureCodeGeneration)
     {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngineExtensions.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngineExtensions.cs
index 8db362d70ab..89c00fac19b 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngineExtensions.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorProjectEngineExtensions.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Generic;
 using System.Collections.Immutable;
 
 namespace Microsoft.AspNetCore.Razor.Language;
@@ -32,21 +31,21 @@ public static RazorCodeDocument CreateCodeDocument(
     public static RazorCodeDocument CreateCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorSourceDocument source,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(source, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorSourceDocument source,
         RazorFileKind fileKind,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(source, fileKind, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorSourceDocument source,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(source, importSources: importSources, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateCodeDocument(
@@ -54,7 +53,7 @@ public static RazorCodeDocument CreateCodeDocument(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(source, fileKind, importSources, tagHelpers);
 
     private static RazorCodeDocument CreateCodeDocumentCore(
@@ -62,7 +61,7 @@ private static RazorCodeDocument CreateCodeDocumentCore(
         RazorSourceDocument source,
         RazorFileKind? fileKind = null,
         ImmutableArray<RazorSourceDocument> importSources = default,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers = null)
+        TagHelperCollection? tagHelpers = null)
     {
         var fileKindValue = fileKind ?? (source.FilePath is string filePath
             ? FileKinds.GetFileKindFromPath(filePath)
@@ -93,21 +92,21 @@ public static RazorCodeDocument CreateDesignTimeCodeDocument(
     public static RazorCodeDocument CreateDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorSourceDocument source,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(source, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorSourceDocument source,
         RazorFileKind fileKind,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(source, fileKind, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorSourceDocument source,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(source, importSources: importSources, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateDesignTimeCodeDocument(
@@ -115,7 +114,7 @@ public static RazorCodeDocument CreateDesignTimeCodeDocument(
         RazorSourceDocument source,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(source, fileKind, importSources, tagHelpers);
 
     private static RazorCodeDocument CreateDesignTimeCodeDocumentCore(
@@ -123,7 +122,7 @@ private static RazorCodeDocument CreateDesignTimeCodeDocumentCore(
         RazorSourceDocument source,
         RazorFileKind? fileKind = null,
         ImmutableArray<RazorSourceDocument> importSources = default,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers = null)
+        TagHelperCollection? tagHelpers = null)
     {
         var fileKindValue = fileKind ?? (source.FilePath is string filePath
             ? FileKinds.GetFileKindFromPath(filePath)
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/SyntaxSerializer.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/SyntaxSerializer.cs
index ba11e20c6ee..363f4ebb7f2 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/SyntaxSerializer.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Syntax/SyntaxSerializer.cs
@@ -133,12 +133,12 @@ private void WriteTagHelperElement(MarkupTagHelperElementSyntax node)
         WriteValue($"{tagHelperInfo.TagName}[{tagHelperInfo.TagMode}]");
 
         // Write descriptors
-        foreach (var descriptor in tagHelperInfo.BindingResult.Descriptors)
+        foreach (var tagHelper in tagHelperInfo.BindingResult.TagHelpers)
         {
             WriteSeparator();
 
             // Get the type name without the namespace.
-            var typeName = descriptor.Name[(descriptor.Name.LastIndexOf('.') + 1)..];
+            var typeName = tagHelper.Name[(tagHelper.Name.LastIndexOf('.') + 1)..];
             WriteValue(typeName);
         }
     }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinder.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinder.cs
index c48b61748f1..90d57d1577b 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinder.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinder.cs
@@ -15,28 +15,28 @@ namespace Microsoft.AspNetCore.Razor.Language;
 /// </summary>
 internal sealed partial class TagHelperBinder
 {
-    private readonly TagHelperSet _catchAllDescriptors;
-    private readonly ReadOnlyDictionary<string, TagHelperSet> _tagNameToDescriptorsMap;
+    private readonly TagHelperSet _catchAllTagHelpers;
+    private readonly ReadOnlyDictionary<string, TagHelperSet> _tagNameToTagHelpersMap;
 
     public string? TagNamePrefix { get; }
-    public ImmutableArray<TagHelperDescriptor> Descriptors { get; }
+    public TagHelperCollection TagHelpers { get; }
 
     /// <summary>
     /// Instantiates a new instance of the <see cref="TagHelperBinder"/>.
     /// </summary>
     /// <param name="tagNamePrefix">The tag helper prefix being used by the document.</param>
-    /// <param name="descriptors">The <see cref="TagHelperDescriptor"/>s that the <see cref="TagHelperBinder"/>
+    /// <param name="tagHelpers">The <see cref="TagHelperDescriptor"/>s that the <see cref="TagHelperBinder"/>
     /// will pull from.</param>
-    public TagHelperBinder(string? tagNamePrefix, ImmutableArray<TagHelperDescriptor> descriptors)
+    public TagHelperBinder(string? tagNamePrefix, TagHelperCollection tagHelpers)
     {
         TagNamePrefix = tagNamePrefix;
-        Descriptors = descriptors.NullToEmpty();
+        TagHelpers = tagHelpers;
 
-        ProcessDescriptors(descriptors, tagNamePrefix, out _tagNameToDescriptorsMap, out _catchAllDescriptors);
+        ProcessDescriptors(tagHelpers, tagNamePrefix, out _tagNameToTagHelpersMap, out _catchAllTagHelpers);
     }
 
     private static void ProcessDescriptors(
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection descriptors,
         string? tagNamePrefix,
         out ReadOnlyDictionary<string, TagHelperSet> tagNameToDescriptorsMap,
         out TagHelperSet catchAllDescriptors)
@@ -47,29 +47,19 @@ private static void ProcessDescriptors(
         // Keep track of what needs to be added in the second pass.
         // There will be an entry for every tag matching rule.
         // Each entry consists of an index to identify a builder and the TagHelperDescriptor to add to it.
-        using var toAdd = new MemoryBuilder<(int, TagHelperDescriptor)>(initialCapacity: descriptors.Length * 4, clearArray: true);
+        using var toAdd = new MemoryBuilder<(int, TagHelperDescriptor)>(initialCapacity: descriptors.Count * 4, clearArray: true);
 
         // Use a special TagHelperSet.Builder to track catch-all tag helpers.
         var catchAllBuilder = new TagHelperSet.Builder();
 
         // At most, there should only be one catch-all tag helper per descriptor.
-        using var catchAllToAdd = new MemoryBuilder<TagHelperDescriptor>(initialCapacity: descriptors.Length, clearArray: true);
+        using var catchAllToAdd = new MemoryBuilder<TagHelperDescriptor>(initialCapacity: descriptors.Count, clearArray: true);
 
         // The builders are indexed using a map of "tag name" to the index of the builder in the array.
         using var _1 = SpecializedPools.GetPooledStringDictionary<int>(ignoreCase: true, out var tagNameToBuilderIndexMap);
-        using var _2 = HashSetPool<TagHelperDescriptor>.GetPooledObject(out var tagHelperSet);
-
-#if NET
-        tagHelperSet.EnsureCapacity(descriptors.Length);
-#endif
 
         foreach (var tagHelper in descriptors)
         {
-            if (!tagHelperSet.Add(tagHelper))
-            {
-                // We've already seen this tag helper. Skip.
-                continue;
-            }
 
             foreach (var rule in tagHelper.TagMatchingRules)
             {
@@ -167,7 +157,7 @@ private static void ProcessDescriptors(
         using var pooledSet = HashSetPool<TagHelperDescriptor>.GetPooledObject(out var distinctSet);
 
         // First, try any tag helpers with this tag name.
-        if (_tagNameToDescriptorsMap.TryGetValue(tagName, out var matchingDescriptors))
+        if (_tagNameToTagHelpersMap.TryGetValue(tagName, out var matchingDescriptors))
         {
             CollectBoundRulesInfo(
                 matchingDescriptors,
@@ -177,7 +167,7 @@ private static void ProcessDescriptors(
 
         // Next, try any "catch all" descriptors.
         CollectBoundRulesInfo(
-            _catchAllDescriptors,
+            _catchAllTagHelpers,
             tagNameSpan, parentTagNameSpan, attributes,
             ref resultsBuilder.AsRef(), ref tempRulesBuilder.AsRef(), distinctSet);
 
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinding.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinding.cs
index d67122cf217..4d9d796b565 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinding.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperBinding.cs
@@ -1,9 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using Microsoft.AspNetCore.Razor.Threading;
 
 namespace Microsoft.AspNetCore.Razor.Language;
 
@@ -15,7 +15,15 @@ internal sealed class TagHelperBinding
     public string? ParentTagName { get; }
     public ImmutableArray<KeyValuePair<string, string>> Attributes { get; }
 
-    private ImmutableArray<TagHelperDescriptor> _descriptors;
+    private LazyValue<ImmutableArray<TagHelperBoundRulesInfo>, TagHelperCollection> _lazyTagHelpers = new(static allBoundRules =>
+        TagHelperCollection.Build(allBoundRules, initialCapacity: allBoundRules.Length, static (ref builder, allBoundRules) =>
+        {
+            foreach (var boundRule in allBoundRules)
+            {
+                builder.Add(boundRule.Descriptor);
+            }
+        }));
+
     private bool? _isAttributeMatch;
 
     internal TagHelperBinding(
@@ -32,18 +40,7 @@ internal TagHelperBinding(
         TagNamePrefix = tagNamePrefix;
     }
 
-    public ImmutableArray<TagHelperDescriptor> Descriptors
-    {
-        get
-        {
-            if (_descriptors.IsDefault)
-            {
-                ImmutableInterlocked.InterlockedInitialize(ref _descriptors, AllBoundRules.SelectAsArray(x => x.Descriptor));
-            }
-
-            return _descriptors;
-        }
-    }
+    public TagHelperCollection TagHelpers => _lazyTagHelpers.GetValue(AllBoundRules);
 
     public ImmutableArray<TagMatchingRuleDescriptor> GetBoundRules(TagHelperDescriptor descriptor)
         => AllBoundRules.First(descriptor, static (info, d) => info.Descriptor.Equals(d)).Rules;
@@ -62,13 +59,13 @@ public bool IsAttributeMatch
     {
         get
         {
-            return _isAttributeMatch ??= ComputeIsAttributeMatch(Descriptors);
+            return _isAttributeMatch ??= ComputeIsAttributeMatch(TagHelpers);
 
-            static bool ComputeIsAttributeMatch(ImmutableArray<TagHelperDescriptor> descriptors)
+            static bool ComputeIsAttributeMatch(TagHelperCollection tagHelpers)
             {
-                foreach (var descriptor in descriptors)
+                foreach (var tagHelper in tagHelpers)
                 {
-                    if (!descriptor.ClassifyAttributesOnly)
+                    if (!tagHelper.ClassifyAttributesOnly)
                     {
                         return false;
                     }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperDocumentContext.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperDocumentContext.cs
index 0a9409ac177..4311327518f 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperDocumentContext.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperDocumentContext.cs
@@ -1,9 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
-using System.Collections.Immutable;
-
 namespace Microsoft.AspNetCore.Razor.Language;
 
 /// <summary>
@@ -13,22 +10,26 @@ namespace Microsoft.AspNetCore.Razor.Language;
 internal sealed class TagHelperDocumentContext
 {
     public string? Prefix { get; }
-    public ImmutableArray<TagHelperDescriptor> TagHelpers { get; }
+    public TagHelperCollection TagHelpers { get; }
 
     private TagHelperBinder? _binder;
 
-    private TagHelperDocumentContext(string? prefix, ImmutableArray<TagHelperDescriptor> tagHelpers)
+    private TagHelperDocumentContext(string? prefix, TagHelperCollection tagHelpers)
     {
         Prefix = prefix;
         TagHelpers = tagHelpers;
     }
 
-    public static TagHelperDocumentContext Create(string? prefix, ImmutableArray<TagHelperDescriptor> tagHelpers)
+    public static TagHelperDocumentContext Create(TagHelperCollection tagHelpers)
+    {
+        ArgHelper.ThrowIfNull(tagHelpers);
+
+        return new(prefix: null, tagHelpers);
+    }
+
+    public static TagHelperDocumentContext Create(string? prefix, TagHelperCollection tagHelpers)
     {
-        if (tagHelpers.IsDefault)
-        {
-            throw new ArgumentNullException(nameof(tagHelpers));
-        }
+        ArgHelper.ThrowIfNull(tagHelpers);
 
         return new(prefix, tagHelpers);
     }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperMatchingConventions.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperMatchingConventions.cs
index 3d6e23a4b48..4689327fc06 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperMatchingConventions.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperMatchingConventions.cs
@@ -187,7 +187,7 @@ private static bool TryGetBoundAttributeParameter(string fullAttributeName, out
     ///  for the specified attribute name. Each successful match is added to the provided matches collection.
     /// </remarks>
     public static void GetAttributeMatches(
-        ImmutableArray<TagHelperDescriptor> tagHelpers,
+        TagHelperCollection tagHelpers,
         string name,
         ref PooledArrayBuilder<TagHelperAttributeMatch> matches)
     {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorGeneratorResult.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorGeneratorResult.cs
index 943913aa799..b7aab9a94ab 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorGeneratorResult.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorGeneratorResult.cs
@@ -1,15 +1,14 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System.Collections.Generic;
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
+using System.Collections.Immutable;
 
 namespace Microsoft.NET.Sdk.Razor.SourceGenerators
 {
-    internal sealed class RazorGeneratorResult(IReadOnlyList<TagHelperDescriptor> tagHelpers, ImmutableDictionary<string, (string hintName, RazorCodeDocument document)> filePathToDocument, ImmutableDictionary<string, string> hintNameToFilePath)
+    internal sealed class RazorGeneratorResult(TagHelperCollection tagHelpers, ImmutableDictionary<string, (string hintName, RazorCodeDocument document)> filePathToDocument, ImmutableDictionary<string, string> hintNameToFilePath)
     {
-        public IReadOnlyList<TagHelperDescriptor> TagHelpers => tagHelpers;
+        public TagHelperCollection TagHelpers => tagHelpers;
 
         public RazorCodeDocument? GetCodeDocument(string physicalPath) => filePathToDocument.TryGetValue(physicalPath, out var pair) ? pair.document : null;
 
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorSourceGenerator.AllTagHelpers.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorSourceGenerator.AllTagHelpers.cs
deleted file mode 100644
index 6852d7c9053..00000000000
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorSourceGenerator.AllTagHelpers.cs
+++ /dev/null
@@ -1,80 +0,0 @@
-// Copyright (c) .NET Foundation. All rights reserved.
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
-
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using Microsoft.AspNetCore.Razor.Language;
-
-namespace Microsoft.NET.Sdk.Razor.SourceGenerators
-{
-    public partial class RazorSourceGenerator
-    {
-        /// <summary>
-        ///  Helper class that joins together two lists of tag helpers to avoid allocating
-        ///  a new array to copy them to.
-        /// </summary>
-        private sealed class AllTagHelpers : IReadOnlyList<TagHelperDescriptor>
-        {
-            private static readonly List<TagHelperDescriptor> s_emptyList = new();
-
-            public static readonly AllTagHelpers Empty = new(
-                tagHelpersFromCompilation: null,
-                tagHelpersFromReferences: null);
-
-            private readonly List<TagHelperDescriptor> _tagHelpersFromCompilation;
-            private readonly List<TagHelperDescriptor> _tagHelpersFromReferences;
-
-            private AllTagHelpers(
-                List<TagHelperDescriptor>? tagHelpersFromCompilation,
-                List<TagHelperDescriptor>? tagHelpersFromReferences)
-            {
-                _tagHelpersFromCompilation = tagHelpersFromCompilation ?? s_emptyList;
-                _tagHelpersFromReferences = tagHelpersFromReferences ?? s_emptyList;
-            }
-
-            public static AllTagHelpers Create(
-                List<TagHelperDescriptor>? tagHelpersFromCompilation,
-                List<TagHelperDescriptor>? tagHelpersFromReferences)
-            {
-                return tagHelpersFromCompilation is null or [] && tagHelpersFromReferences is null or []
-                    ? Empty
-                    : new(tagHelpersFromCompilation, tagHelpersFromReferences);
-            }
-
-            public TagHelperDescriptor this[int index]
-            {
-                get
-                {
-                    if (index >= 0)
-                    {
-                        return index < _tagHelpersFromCompilation.Count
-                            ? _tagHelpersFromCompilation[index]
-                            : _tagHelpersFromReferences[index - _tagHelpersFromCompilation.Count];
-                    }
-
-                    throw new IndexOutOfRangeException();
-                }
-            }
-
-            public int Count
-                => _tagHelpersFromCompilation.Count + _tagHelpersFromReferences.Count;
-
-            public IEnumerator<TagHelperDescriptor> GetEnumerator()
-            {
-                foreach (var tagHelper in _tagHelpersFromCompilation)
-                {
-                    yield return tagHelper;
-                }
-
-                foreach (var tagHelper in _tagHelpersFromReferences)
-                {
-                    yield return tagHelper;
-                }
-            }
-
-            IEnumerator IEnumerable.GetEnumerator()
-                => GetEnumerator();
-        }
-    }
-}
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorSourceGenerator.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorSourceGenerator.cs
index faf72056bfb..66c6ca5d9b5 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorSourceGenerator.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/RazorSourceGenerator.cs
@@ -125,21 +125,21 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                 .Select(static (pair, cancellationToken) =>
                 {
                     var ((compilation, razorSourceGeneratorOptions), isGeneratorSuppressed) = pair;
-                    var results = new List<TagHelperDescriptor>();
-
                     if (isGeneratorSuppressed)
                     {
-                        return results;
+                        return [];
                     }
 
                     RazorSourceGeneratorEventSource.Log.DiscoverTagHelpersFromCompilationStart();
                     var tagHelperFeature = GetStaticTagHelperFeature(compilation);
 
-                    tagHelperFeature.CollectDescriptors(compilation.Assembly, results, cancellationToken);
+                    using var builder = new TagHelperCollection.Builder();
+
+                    tagHelperFeature.CollectDescriptors(compilation.Assembly, builder, cancellationToken);
 
                     RazorSourceGeneratorEventSource.Log.DiscoverTagHelpersFromCompilationStop();
 
-                    return results;
+                    return builder.ToCollection();
                 })
                 .WithLambdaComparer(static (a, b) => a!.SequenceEqual(b!));
 
@@ -222,7 +222,7 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                     if (!hasRazorFiles)
                     {
                         // If there's no razor code in this app, don't do anything.
-                        return null;
+                        return [];
                     }
 
                     RazorSourceGeneratorEventSource.Log.DiscoverTagHelpersFromReferencesStart();
@@ -230,26 +230,26 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
 
                     // Typically a project with Razor files will have many tag helpers in references.
                     // So, we start with a larger capacity to avoid extra array copies.
-                    var results = new List<TagHelperDescriptor>(capacity: 128);
+                    using var builder = new TagHelperCollection.Builder();
 
                     foreach (var reference in compilation.References)
                     {
                         if (compilation.GetAssemblyOrModuleSymbol(reference) is IAssemblySymbol assembly)
                         {
-                            tagHelperFeature.CollectDescriptors(assembly, results, cancellationToken);
+                            tagHelperFeature.CollectDescriptors(assembly, builder, cancellationToken);
                         }
                     }
 
                     RazorSourceGeneratorEventSource.Log.DiscoverTagHelpersFromReferencesStop();
 
-                    return results;
+                    return builder.ToCollection();
                 });
 
             var allTagHelpers = tagHelpersFromCompilation
                 .Combine(tagHelpersFromReferences)
                 .Select(static (pair, _) =>
                 {
-                    return AllTagHelpers.Create(tagHelpersFromCompilation: pair.Left, tagHelpersFromReferences: pair.Right);
+                    return TagHelperCollection.Merge(pair.Left, pair.Right);
                 });
 
             var withOptions = sourceItems
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/SourceGeneratorProjectEngine.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/SourceGeneratorProjectEngine.cs
index 120c2d5f666..67b0359dadf 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/SourceGeneratorProjectEngine.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/SourceGeneratorProjectEngine.cs
@@ -65,7 +65,7 @@ public SourceGeneratorRazorCodeDocument ProcessInitialParse(RazorProjectItem pro
         return new SourceGeneratorRazorCodeDocument(codeDocument);
     }
 
-    public SourceGeneratorRazorCodeDocument ProcessTagHelpers(SourceGeneratorRazorCodeDocument sgDocument, IReadOnlyList<TagHelperDescriptor> tagHelpers, bool checkForIdempotency, CancellationToken cancellationToken)
+    public SourceGeneratorRazorCodeDocument ProcessTagHelpers(SourceGeneratorRazorCodeDocument sgDocument, TagHelperCollection tagHelpers, bool checkForIdempotency, CancellationToken cancellationToken)
     {
         Debug.Assert(sgDocument.CodeDocument.GetPreTagHelperSyntaxTree() is not null);
 
@@ -75,34 +75,32 @@ public SourceGeneratorRazorCodeDocument ProcessTagHelpers(SourceGeneratorRazorCo
         if (checkForIdempotency && codeDocument.TryGetTagHelpers(out var previousTagHelpers))
         {
             // compare the tag helpers with the ones the document last used
-            if (Enumerable.SequenceEqual(tagHelpers, previousTagHelpers))
+            if (tagHelpers.Equals(previousTagHelpers))
             {
                 // tag helpers are the same, nothing to do!
                 return sgDocument;
             }
-            else
+
+            // tag helpers have changed, figure out if we need to re-write
+            var previousTagHelpersInScope = codeDocument.GetRequiredTagHelperContext().TagHelpers;
+            var previousUsedTagHelpers = codeDocument.GetRequiredReferencedTagHelpers();
+
+            // re-run discovery to figure out which tag helpers are now in scope for this document
+            codeDocument.SetTagHelpers(tagHelpers);
+            _discoveryPhase.Execute(codeDocument, cancellationToken);
+            var tagHelpersInScope = codeDocument.GetRequiredTagHelperContext().TagHelpers;
+
+            // Check if any new tag helpers were added or ones we previously used were removed
+            var newVisibleTagHelpers = tagHelpersInScope.Except(previousTagHelpersInScope);
+            var newUnusedTagHelpers = previousUsedTagHelpers.Except(tagHelpersInScope);
+            if (!newVisibleTagHelpers.Any() && !newUnusedTagHelpers.Any())
             {
-                // tag helpers have changed, figure out if we need to re-write
-                var previousTagHelpersInScope = codeDocument.GetRequiredTagHelperContext().TagHelpers;
-                var previousUsedTagHelpers = codeDocument.GetRequiredReferencedTagHelpers();
-
-                // re-run discovery to figure out which tag helpers are now in scope for this document
-                codeDocument.SetTagHelpers(tagHelpers);
-                _discoveryPhase.Execute(codeDocument, cancellationToken);
-                var tagHelpersInScope = codeDocument.GetRequiredTagHelperContext().TagHelpers;
-
-                // Check if any new tag helpers were added or ones we previously used were removed
-                var newVisibleTagHelpers = tagHelpersInScope.Except(previousTagHelpersInScope);
-                var newUnusedTagHelpers = previousUsedTagHelpers.Except(tagHelpersInScope);
-                if (!newVisibleTagHelpers.Any() && !newUnusedTagHelpers.Any())
-                {
-                    // No newly visible tag helpers, and any that got removed weren't used by this document anyway
-                    return sgDocument;
-                }
-
-                // We need to re-write the document, but can skip the scoping as we just performed it
-                startIndex = _rewritePhaseIndex;
+                // No newly visible tag helpers, and any that got removed weren't used by this document anyway
+                return sgDocument;
             }
+
+            // We need to re-write the document, but can skip the scoping as we just performed it
+            startIndex = _rewritePhaseIndex;
         }
         else
         {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/StaticCompilationTagHelperFeature.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/StaticCompilationTagHelperFeature.cs
index 5f5a67e224a..fb0bb071f0b 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/StaticCompilationTagHelperFeature.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/SourceGenerators/StaticCompilationTagHelperFeature.cs
@@ -16,7 +16,7 @@ internal sealed class StaticCompilationTagHelperFeature(Compilation compilation)
 
         public void CollectDescriptors(
             IAssemblySymbol? targetAssembly,
-            List<TagHelperDescriptor> results,
+            TagHelperCollection.Builder results,
             CancellationToken cancellationToken)
         {
             if (_providers.IsDefaultOrEmpty)
@@ -32,12 +32,12 @@ public void CollectDescriptors(
             }
         }
 
-        IReadOnlyList<TagHelperDescriptor> ITagHelperFeature.GetDescriptors(CancellationToken cancellationToken)
+        TagHelperCollection ITagHelperFeature.GetTagHelpers(CancellationToken cancellationToken)
         {
-            var results = new List<TagHelperDescriptor>();
-            CollectDescriptors(targetAssembly: null, results, cancellationToken);
+            using var builder = new TagHelperCollection.Builder();
+            CollectDescriptors(targetAssembly: null, builder, cancellationToken);
 
-            return results;
+            return builder.ToCollection();
         }
 
         protected override void OnInitialized()
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor/test/CompilationTagHelperFeatureTest.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor/test/CompilationTagHelperFeatureTest.cs
index bb4fd061db3..5d9815355aa 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor/test/CompilationTagHelperFeatureTest.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor/test/CompilationTagHelperFeatureTest.cs
@@ -90,7 +90,7 @@ public void GetDescriptors_DoesNotSetCompilation_IfCompilationIsInvalid()
         var feature = engine.Engine.GetFeatures<CompilationTagHelperFeature>().First();
 
         // Act
-        var result = feature.GetDescriptors();
+        var result = feature.GetTagHelpers();
 
         // Assert
         Assert.Empty(result);
@@ -130,7 +130,7 @@ public void GetDescriptors_SetsCompilation_IfCompilationIsValid()
         var feature = engine.Engine.GetFeatures<CompilationTagHelperFeature>().First();
 
         // Act
-        var result = feature.GetDescriptors();
+        var result = feature.GetTagHelpers();
 
         // Assert
         Assert.Empty(result);
diff --git a/src/Compiler/perf/Microbenchmarks/RazorTagHelperParsingBenchmark.cs b/src/Compiler/perf/Microbenchmarks/RazorTagHelperParsingBenchmark.cs
index eeec0a1226b..98c1bf61b01 100644
--- a/src/Compiler/perf/Microbenchmarks/RazorTagHelperParsingBenchmark.cs
+++ b/src/Compiler/perf/Microbenchmarks/RazorTagHelperParsingBenchmark.cs
@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.IO;
 using System.Threading;
 using BenchmarkDotNet.Attributes;
@@ -63,18 +61,18 @@ public void TagHelper_ComponentDirectiveVisitor()
         ComponentDirectiveVisitor.Visit(SyntaxTree);
     }
 
-    private static ImmutableArray<TagHelperDescriptor> ReadTagHelpers(string filePath)
+    private static TagHelperCollection ReadTagHelpers(string filePath)
     {
         using var reader = new StreamReader(filePath);
-        return JsonDataConvert.DeserializeTagHelperArray(reader);
+        var array = JsonDataConvert.DeserializeTagHelperArray(reader);
+
+        return TagHelperCollection.Create(array);
     }
 
-    private sealed class StaticTagHelperFeature(IReadOnlyList<TagHelperDescriptor> descriptors)
+    private sealed class StaticTagHelperFeature(TagHelperCollection tagHelpers)
         : RazorEngineFeatureBase, ITagHelperFeature
     {
-        public IReadOnlyList<TagHelperDescriptor> Descriptors { get; } = descriptors;
-
-        public IReadOnlyList<TagHelperDescriptor> GetDescriptors(CancellationToken cancellationToken = default)
-            => Descriptors;
+        public TagHelperCollection GetTagHelpers(CancellationToken cancellationToken = default)
+            => tagHelpers;
     }
 }
diff --git a/src/Compiler/perf/Microbenchmarks/TagHelperBinderBenchmark.cs b/src/Compiler/perf/Microbenchmarks/TagHelperBinderBenchmark.cs
index bfa62372895..dc50584e42c 100644
--- a/src/Compiler/perf/Microbenchmarks/TagHelperBinderBenchmark.cs
+++ b/src/Compiler/perf/Microbenchmarks/TagHelperBinderBenchmark.cs
@@ -42,7 +42,7 @@ public void ConstructTagHelperBinders()
     {
         for (var i = 0; i < Count; i++)
         {
-            _binders[i] = new TagHelperBinder(tagNamePrefix: null, _tagHelpers);
+            _binders[i] = new TagHelperBinder(tagNamePrefix: null, [.. _tagHelpers]);
         }
     }
 
@@ -51,7 +51,7 @@ public void ConstructTagHelperBinderWithPrefix()
     {
         for (var i = 0; i < Count; i++)
         {
-            _binders[i] = new TagHelperBinder(tagNamePrefix: "abc", _tagHelpers);
+            _binders[i] = new TagHelperBinder(tagNamePrefix: "abc", [.. _tagHelpers]);
         }
     }
 }
diff --git a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/RazorLanguageServerBenchmarkBase.cs b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/RazorLanguageServerBenchmarkBase.cs
index c964397698c..7ad2bd45e2d 100644
--- a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/RazorLanguageServerBenchmarkBase.cs
+++ b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/RazorLanguageServerBenchmarkBase.cs
@@ -71,7 +71,7 @@ await projectManager.UpdateAsync(
             updater =>
             {
                 updater.AddProject(hostProject);
-                var projectWorkspaceState = ProjectWorkspaceState.Create(CommonResources.LegacyTagHelpers);
+                var projectWorkspaceState = ProjectWorkspaceState.Create([.. CommonResources.LegacyTagHelpers]);
                 updater.UpdateProjectWorkspaceState(hostProject.Key, projectWorkspaceState);
                 updater.AddDocument(hostProject.Key, hostDocument, text);
             },
diff --git a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/TagHelperCompletionBenchmark.cs b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/TagHelperCompletionBenchmark.cs
index 962fd66b8d7..4b6158be6e3 100644
--- a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/TagHelperCompletionBenchmark.cs
+++ b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/LanguageServer/TagHelperCompletionBenchmark.cs
@@ -31,7 +31,7 @@ public object GetAttributeCompletions()
     {
         var tagHelperCompletionService = new TagHelperCompletionService();
         var context = new AttributeCompletionContext(
-            TagHelperDocumentContext.Create(prefix: null, CommonResources.TelerikTagHelpers),
+            TagHelperDocumentContext.Create([.. CommonResources.TelerikTagHelpers]),
             existingCompletions: [],
             currentTagName: "PageTitle",
             currentAttributeName: null,
@@ -48,7 +48,7 @@ public object GetElementCompletions()
     {
         var tagHelperCompletionService = new TagHelperCompletionService();
         var context = new ElementCompletionContext(
-            TagHelperDocumentContext.Create(prefix: null, CommonResources.TelerikTagHelpers),
+            TagHelperDocumentContext.Create([.. CommonResources.TelerikTagHelpers]),
             existingCompletions: s_existingElementCompletions,
             containingTagName: null,
             attributes: [],
diff --git a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/CompletionListSerializationBenchmark.cs b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/CompletionListSerializationBenchmark.cs
index 07f643b524d..1aee919617f 100644
--- a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/CompletionListSerializationBenchmark.cs
+++ b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/CompletionListSerializationBenchmark.cs
@@ -6,9 +6,6 @@
 using BenchmarkDotNet.Attributes;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
-using Microsoft.AspNetCore.Razor.LanguageServer;
-using Microsoft.AspNetCore.Razor.LanguageServer.Completion;
-using Microsoft.AspNetCore.Razor.LanguageServer.Hosting;
 using Microsoft.CodeAnalysis.Razor.Completion;
 
 namespace Microsoft.AspNetCore.Razor.Microbenchmarks.Serialization;
@@ -69,7 +66,7 @@ private CompletionList GenerateCompletionList(string documentContent, int queryI
         var sourceDocument = RazorSourceDocument.Create(documentContent, RazorSourceDocumentProperties.Default);
         var codeDocument = RazorCodeDocument.Create(sourceDocument);
         var syntaxTree = RazorSyntaxTree.Parse(sourceDocument);
-        var tagHelperDocumentContext = TagHelperDocumentContext.Create(prefix: string.Empty, CommonResources.LegacyTagHelpers);
+        var tagHelperDocumentContext = TagHelperDocumentContext.Create([.. CommonResources.LegacyTagHelpers]);
 
         var owner = syntaxTree.Root.FindInnermostNode(queryIndex, includeWhitespace: true, walkMarkersBack: true);
         var context = new RazorCompletionContext(codeDocument, queryIndex, owner, syntaxTree, tagHelperDocumentContext);
diff --git a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/RazorProjectInfoSerializationBenchmark.cs b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/RazorProjectInfoSerializationBenchmark.cs
index 8db3ea53989..6b4c3dde1dc 100644
--- a/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/RazorProjectInfoSerializationBenchmark.cs
+++ b/src/Razor/benchmarks/Microsoft.AspNetCore.Razor.Microbenchmarks/Serialization/RazorProjectInfoSerializationBenchmark.cs
@@ -67,7 +67,7 @@ public void Deserialize_Json()
         var projectInfo = DeserializeProjectInfo_Json(reader);
 
         if (projectInfo.ProjectWorkspaceState is null ||
-            projectInfo.ProjectWorkspaceState.TagHelpers.Length != ProjectInfo.ProjectWorkspaceState?.TagHelpers.Length)
+            projectInfo.ProjectWorkspaceState.TagHelpers.Count != ProjectInfo.ProjectWorkspaceState.TagHelpers.Count)
         {
             throw new InvalidDataException();
         }
@@ -89,7 +89,7 @@ public void RoundTrip_Json()
         var projectInfo = DeserializeProjectInfo_Json(reader);
 
         if (projectInfo.ProjectWorkspaceState is null ||
-            projectInfo.ProjectWorkspaceState.TagHelpers.Length != ProjectInfo.ProjectWorkspaceState?.TagHelpers.Length)
+            projectInfo.ProjectWorkspaceState.TagHelpers.Count != ProjectInfo.ProjectWorkspaceState.TagHelpers.Count)
         {
             throw new InvalidDataException();
         }
@@ -128,7 +128,7 @@ public void Deserialize_MessagePack()
         var projectInfo = DeserializeProjectInfo_MessagePack(_projectInfoMessagePackBytes);
 
         if (projectInfo.ProjectWorkspaceState is null ||
-            projectInfo.ProjectWorkspaceState.TagHelpers.Length != ProjectInfo.ProjectWorkspaceState?.TagHelpers.Length)
+            projectInfo.ProjectWorkspaceState.TagHelpers.Count != ProjectInfo.ProjectWorkspaceState.TagHelpers.Count)
         {
             throw new InvalidDataException();
         }
@@ -142,7 +142,7 @@ public void RoundTrip_MessagePack()
         _buffer.Clear();
 
         if (projectInfo.ProjectWorkspaceState is null ||
-            projectInfo.ProjectWorkspaceState.TagHelpers.Length != ProjectInfo.ProjectWorkspaceState?.TagHelpers.Length)
+            projectInfo.ProjectWorkspaceState.TagHelpers.Count != ProjectInfo.ProjectWorkspaceState.TagHelpers.Count)
         {
             throw new InvalidDataException();
         }
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.CodeDocumentWrapper.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.CodeDocumentWrapper.cs
index 21f88c0e7b2..5139552f838 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.CodeDocumentWrapper.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.CodeDocumentWrapper.cs
@@ -47,7 +47,7 @@ public ImmutableArray<TagHelperSpan> GetTagHelperSpans()
             {
                 builder.Add(new TagHelperSpan(
                     ConvertSourceSpan(item.Span),
-                    WrapAll(item.Binding.Descriptors, Wrap)));
+                    WrapAll(item.Binding.TagHelpers, Wrap)));
             }
 
             return builder.ToImmutableAndClear();
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.TagHelperBindingWrapper.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.TagHelperBindingWrapper.cs
index f28d39881aa..9ad1f5b3167 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.TagHelperBindingWrapper.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.TagHelperBindingWrapper.cs
@@ -10,10 +10,10 @@ internal static partial class RazorWrapperFactory
 {
     private class TagHelperBindingWrapper(TagHelperBinding obj) : Wrapper<TagHelperBinding>(obj), IRazorTagHelperBinding
     {
-        private ImmutableArray<IRazorTagHelperDescriptor> _descriptors;
+        private ImmutableArray<IRazorTagHelperDescriptor> _tagHelpers;
 
         public ImmutableArray<IRazorTagHelperDescriptor> Descriptors
-            => InitializeArrayWithWrappedItems(ref _descriptors, Object.Descriptors, Wrap);
+            => InitializeArrayWithWrappedItems(ref _tagHelpers, Object.TagHelpers, Wrap);
 
         public ImmutableArray<IRazorTagMatchingRuleDescriptor> GetBoundRules(IRazorTagHelperDescriptor descriptor)
         {
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.cs
index 13ae732235f..19610b602e6 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor/RazorWrapperFactory.cs
@@ -87,6 +87,21 @@ private static ImmutableArray<TResult> InitializeArrayWithWrappedItems<TInner, T
         return location;
     }
 
+    private static ImmutableArray<TResult> InitializeArrayWithWrappedItems<TInner, TResult>(
+        ref ImmutableArray<TResult> location,
+        IEnumerable<TInner> list,
+        Func<TInner, TResult> createWrapper)
+        where TInner : class
+        where TResult : class
+    {
+        if (location.IsDefault)
+        {
+            ImmutableInterlocked.InterlockedInitialize(ref location, WrapAll(list, createWrapper));
+        }
+
+        return location;
+    }
+
     private static T Unwrap<T>(object obj)
         where T : class
         => ((Wrapper<T>)obj).Object;
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Diagnostics/MissingTagHelperTelemetryReporter.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Diagnostics/MissingTagHelperTelemetryReporter.cs
index e6a3944d3cc..2b4b95ff0da 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Diagnostics/MissingTagHelperTelemetryReporter.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Diagnostics/MissingTagHelperTelemetryReporter.cs
@@ -32,7 +32,7 @@ public async ValueTask ReportRZ10012TelemetryAsync(DocumentContext documentConte
         }
 
         var tagHelpers = await documentContext.Project.GetTagHelpersAsync(cancellationToken).ConfigureAwait(false);
-        var tagHelperCount = tagHelpers.Length;
+        var tagHelperCount = tagHelpers.Count;
         var shouldReport = false;
 
         ImmutableInterlocked.AddOrUpdate(
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/RazorProjectService.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/RazorProjectService.cs
index 24891410954..a5aad1a5b0a 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/RazorProjectService.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/ProjectSystem/RazorProjectService.cs
@@ -400,9 +400,9 @@ private Task AddOrUpdateProjectCoreAsync(
 
                 UpdateProjectDocuments(updater, documents, project.Key);
 
-                if (!projectWorkspaceState.Equals(ProjectWorkspaceState.Default))
+                if (!projectWorkspaceState.IsDefault)
                 {
-                    _logger.LogInformation($"Updating project '{project.Key}' TagHelpers ({projectWorkspaceState.TagHelpers.Length}).");
+                    _logger.LogInformation($"Updating project '{project.Key}' TagHelpers ({projectWorkspaceState.TagHelpers.Count}).");
                 }
 
                 updater.UpdateProjectWorkspaceState(project.Key, projectWorkspaceState);
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/GenerateMethodCodeActionProvider.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/GenerateMethodCodeActionProvider.cs
index a0db39d014f..20f840812dc 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/GenerateMethodCodeActionProvider.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/GenerateMethodCodeActionProvider.cs
@@ -116,20 +116,20 @@ private static bool TryGetEventNameAndMethodName(
         }
 
         var found = false;
-        foreach (var tagHelperDescriptor in binding.Descriptors)
+        foreach (var tagHelper in binding.TagHelpers)
         {
-            foreach (var attribute in tagHelperDescriptor.BoundAttributes)
+            foreach (var attribute in tagHelper.BoundAttributes)
             {
                 if (attribute.Name == attributeName)
                 {
                     // We found the attribute that matches the directive attribute, now we need to check if the
                     // tag helper it's bound to is an event handler. This filters out things like @ref and @rendermode
-                    if (tagHelperDescriptor.Kind == TagHelperKind.EventHandler)
+                    if (tagHelper.Kind == TagHelperKind.EventHandler)
                     {
                         // An event handler like "@onclick"
-                        eventParameterType = tagHelperDescriptor.GetEventArgsType() ?? "";
+                        eventParameterType = tagHelper.GetEventArgsType() ?? "";
                     }
-                    else if (tagHelperDescriptor.Kind == TagHelperKind.Bind)
+                    else if (tagHelper.Kind == TagHelperKind.Bind)
                     {
                         // A bind tag helper, so either @bind-XX:after or @bind-XX:set, the latter of which has a parameter
                         if (markupTagHelperDirectiveAttribute.TagHelperAttributeInfo.ParameterName == "set" &&
@@ -181,9 +181,9 @@ private static bool TryGetEventNameAndMethodName(
         eventParameterType = null;
         allowAsync = true;
 
-        foreach (var tagHelperDescriptor in binding.Descriptors)
+        foreach (var tagHelper in binding.TagHelpers)
         {
-            foreach (var attribute in tagHelperDescriptor.BoundAttributes)
+            foreach (var attribute in tagHelper.BoundAttributes)
             {
                 if (attribute.Name == markupTagHelperDirectiveAttribute.TagHelperAttributeInfo.Name)
                 {
@@ -202,7 +202,7 @@ private static bool TryGetEventNameAndMethodName(
 
                         if (attribute.IsGenericTypedProperty())
                         {
-                            if (tagHelperDescriptor.TryGetGenericTypeNameFromComponent(binding, out var genericType) &&
+                            if (tagHelper.TryGetGenericTypeNameFromComponent(binding, out var genericType) &&
                                 ComponentAttributeIntermediateNode.TryGetGenericActionArgument(attribute.TypeName.AsMemory(), genericType, out var argument))
                             {
                                 eventParameterType = argument.ToString();
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyFullyQualifiedComponentCodeActionProvider.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyFullyQualifiedComponentCodeActionProvider.cs
index ae8fdba5709..7aeabc4e1c0 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyFullyQualifiedComponentCodeActionProvider.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyFullyQualifiedComponentCodeActionProvider.cs
@@ -123,8 +123,8 @@ private static bool IsFullyQualifiedComponent(MarkupTagHelperElementSyntax eleme
         @namespace = string.Empty;
         componentName = string.Empty;
 
-        var descriptors = element.TagHelperInfo.BindingResult.Descriptors;
-        var boundTagHelper = descriptors.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
+        var tagHelpers = element.TagHelperInfo.BindingResult.TagHelpers;
+        var boundTagHelper = tagHelpers.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
         if (boundTagHelper is null)
         {
             return false;
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyTagToSelfClosingCodeActionProvider.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyTagToSelfClosingCodeActionProvider.cs
index e412ae97b03..5afe590e988 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyTagToSelfClosingCodeActionProvider.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/SimplifyTagToSelfClosingCodeActionProvider.cs
@@ -89,7 +89,7 @@ internal static bool IsApplicableTo(MarkupTagHelperElementSyntax markupElementSy
             return false;
         }
 
-        if (markupElementSyntax is not { TagHelperInfo.BindingResult.Descriptors: [.. var descriptors] })
+        if (markupElementSyntax is not { TagHelperInfo.BindingResult.TagHelpers: { Count: > 0 } tagHelpers })
         {
             return false;
         }
@@ -101,7 +101,7 @@ internal static bool IsApplicableTo(MarkupTagHelperElementSyntax markupElementSy
         }
 
         // Get symbols for the markup element
-        var boundTagHelper = descriptors.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
+        var boundTagHelper = tagHelpers.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
         if (boundTagHelper == null)
         {
             return false;
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionContext.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionContext.cs
index 40a2bb2daa7..f55360f696a 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionContext.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionContext.cs
@@ -2,10 +2,11 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Immutable;
+using Microsoft.AspNetCore.Razor.Language;
 
 namespace Microsoft.CodeAnalysis.Razor.Completion;
 
-internal record DirectiveAttributeCompletionContext
+internal sealed record DirectiveAttributeCompletionContext
 {
     public required string SelectedAttributeName { get; init; }
     public string? SelectedParameterName { get; init; }
@@ -14,4 +15,13 @@ internal record DirectiveAttributeCompletionContext
     public bool InAttributeName { get; init; } = true;
     public bool InParameterName { get; init; }
     public RazorCompletionOptions Options { get; init; }
+
+    public bool AlreadySatisfiesParameter(BoundAttributeParameterDescriptor parameter, BoundAttributeDescriptor attribute)
+        => ExistingAttributes.Any(
+            (parameter, attribute),
+            static (name, arg) =>
+                TagHelperMatchingConventions.SatisfiesBoundAttributeWithParameter(arg.parameter, name, arg.attribute));
+
+    public bool CanSatisfyAttribute(BoundAttributeDescriptor attribute)
+        => TagHelperMatchingConventions.CanSatisfyBoundAttribute(SelectedAttributeName, attribute);
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.AttributeCompletionDetails.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.AttributeCompletionDetails.cs
new file mode 100644
index 00000000000..564cb17646f
--- /dev/null
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.AttributeCompletionDetails.cs
@@ -0,0 +1,32 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis.Razor.Tooltip;
+
+namespace Microsoft.CodeAnalysis.Razor.Completion;
+
+internal partial class DirectiveAttributeCompletionItemProvider
+{
+    private readonly struct AttributeCompletionDetails(
+        RazorCompletionItemKind kind,
+        ImmutableArray<BoundAttributeDescriptionInfo> descriptions = default,
+        ImmutableArray<RazorCommitCharacter> commitCharacters = default)
+    {
+        public RazorCompletionItemKind Kind => kind;
+
+        public ImmutableArray<BoundAttributeDescriptionInfo> Descriptions => descriptions.NullToEmpty();
+        public ImmutableArray<RazorCommitCharacter> CommitCharacters => commitCharacters.NullToEmpty();
+
+        public void Deconstruct(
+            out RazorCompletionItemKind kind,
+            out ImmutableArray<BoundAttributeDescriptionInfo> descriptions,
+            out ImmutableArray<RazorCommitCharacter> commitCharacters)
+            => (kind, descriptions, commitCharacters) = (Kind, Descriptions, CommitCharacters);
+
+        public void Deconstruct(
+            out ImmutableArray<BoundAttributeDescriptionInfo> descriptions,
+            out ImmutableArray<RazorCommitCharacter> commitCharacters)
+            => (descriptions, commitCharacters) = (Descriptions, CommitCharacters);
+    }
+}
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.DefaultCommitCharacters.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.DefaultCommitCharacters.cs
new file mode 100644
index 00000000000..72236580200
--- /dev/null
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.DefaultCommitCharacters.cs
@@ -0,0 +1,37 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Immutable;
+
+namespace Microsoft.CodeAnalysis.Razor.Completion;
+
+internal partial class DirectiveAttributeCompletionItemProvider
+{
+    private static class DefaultCommitCharacters
+    {
+        private static readonly ImmutableArray<RazorCommitCharacter> s_equalsCommitCharacters = [EqualsCommit(false)];
+        private static readonly ImmutableArray<RazorCommitCharacter> s_equalsSpaceCommitCharacters = [EqualsCommit(false), SpaceCommit];
+        private static readonly ImmutableArray<RazorCommitCharacter> s_snippetEqualsCommitCharacters = [EqualsCommit(true)];
+        private static readonly ImmutableArray<RazorCommitCharacter> s_snippetEqualsSpaceCommitCharacters = [EqualsCommit(true), SpaceCommit];
+        private static readonly ImmutableArray<RazorCommitCharacter> s_spaceCommitCharacters = [SpaceCommit];
+
+        private static RazorCommitCharacter EqualsCommit(bool snippet) => new("=", Insert: !snippet);
+        private static RazorCommitCharacter SpaceCommit => new(" ");
+
+        public static ImmutableArray<RazorCommitCharacter> Get(bool useEquals, bool useSpace, bool useSnippets)
+            => (useEquals, useSpace, useSnippets) switch
+            {
+                // Use equals with or without space (no snippets)
+                (true, false, false) => s_equalsCommitCharacters,
+                (true, true, false) => s_equalsSpaceCommitCharacters,
+
+                // Use equals with or without space (using snippets)
+                (true, false, true) => s_snippetEqualsCommitCharacters,
+                (true, true, true) => s_snippetEqualsSpaceCommitCharacters,
+
+                // No equals and with or without space (snippets not relevant)
+                (false, true, _) => s_spaceCommitCharacters,
+                (false, false, _) => []
+            };
+    }
+}
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.cs
index 687a9df8cda..ceeef3f3321 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/DirectiveAttributeCompletionItemProvider.cs
@@ -6,6 +6,7 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
+using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.PooledObjects;
@@ -15,13 +16,11 @@
 
 namespace Microsoft.CodeAnalysis.Razor.Completion;
 
-internal class DirectiveAttributeCompletionItemProvider : DirectiveAttributeCompletionItemProviderBase
+internal partial class DirectiveAttributeCompletionItemProvider : DirectiveAttributeCompletionItemProviderBase
 {
-    private static readonly string s_quotedAttributeValueSnippet = "=\"$0\"";
-    private static readonly string s_unquotedAttributeValueSnippet = "=$0";
-
-    private static readonly ImmutableArray<RazorCommitCharacter> s_equalsCommitCharacters = [new("=")];
-    private static readonly ImmutableArray<RazorCommitCharacter> s_snippetEqualsCommitCharacters = [new("=", Insert: false)];
+    private const string Ellipsis = "...";
+    private const string QuotedAttributeValueSnippetSuffix = "=\"$0\"";
+    private const string UnquotedAttributeValueSnippetSuffix = "=$0";
 
     public override ImmutableArray<RazorCompletionItem> GetCompletionItems(RazorCompletionContext context)
     {
@@ -67,7 +66,8 @@ public override ImmutableArray<RazorCompletionItem> GetCompletionItems(RazorComp
         }
 
         var inSnippetContext = InSnippetContext(owner, context.Options);
-        var directiveAttributeCompletionContext = new DirectiveAttributeCompletionContext()
+
+        var completionContext = new DirectiveAttributeCompletionContext()
         {
             SelectedAttributeName = attributeName,
             SelectedParameterName = parameterName,
@@ -78,13 +78,11 @@ public override ImmutableArray<RazorCompletionItem> GetCompletionItems(RazorComp
             Options = context.Options
         };
 
-        return GetAttributeCompletions(containingTagName, directiveAttributeCompletionContext, context.TagHelperDocumentContext);
+        return GetAttributeCompletions(containingTagName, completionContext, context.TagHelperDocumentContext);
 
-        static bool InSnippetContext(
-            RazorSyntaxNode owner,
-            RazorCompletionOptions razorCompletionOptions)
+        static bool InSnippetContext(RazorSyntaxNode owner, RazorCompletionOptions options)
         {
-            return razorCompletionOptions.SnippetsSupported
+            return options.SnippetsSupported
                 // Don't create snippet text when attribute is already in the tag and we are trying to replace it
                 // Otherwise you could have something like @onabort=""=""
                 && owner is not (MarkupTagHelperDirectiveAttributeSyntax or MarkupAttributeBlockSyntax)
@@ -95,315 +93,324 @@ static bool InSnippetContext(
     // Internal for testing
     internal static ImmutableArray<RazorCompletionItem> GetAttributeCompletions(
         string containingTagName,
-        DirectiveAttributeCompletionContext context,
-        TagHelperDocumentContext tagHelperDocumentContext)
+        DirectiveAttributeCompletionContext completionContext,
+        TagHelperDocumentContext documentContext)
     {
-        var descriptorsForTag = TagHelperFacts.GetTagHelpersGivenTag(tagHelperDocumentContext, containingTagName, parentTag: null);
-        if (descriptorsForTag.Length == 0)
+        var tagHelpersForTag = TagHelperFacts.GetTagHelpersGivenTag(documentContext, containingTagName, parentTag: null);
+        if (tagHelpersForTag.IsEmpty)
         {
-            // If the current tag has no possible descriptors then we can't have any directive attributes.
+            // If the current tag has no possible tag helpers then we can't have any directive attributes.
             return [];
         }
 
         // Use ordinal dictionary because attributes are case sensitive when matching
-        using var _ = SpecializedPools.GetPooledStringDictionary<(ImmutableArray<BoundAttributeDescriptionInfo>, ImmutableArray<RazorCommitCharacter>, RazorCompletionItemKind kind)>(out var attributeCompletions);
+        using var _ = SpecializedPools.GetPooledStringDictionary<AttributeCompletionDetails>(out var attributeCompletions);
 
-        // Collect indexer descriptors and their parent tag helper type names. Indexer descriptors indicate an attribute prefix
-        // for which they apply. That can be used in an attribute name context to determine potential parameters. Eg,
+        // Collect indexer bound attributes and their parent tag helper type names. Indexer attributes indicate an attribute prefix
+        // for which they apply. That can be used in an attribute name context to determine potential parameters. E.g.,
         // there exists an indexer indicating it applies to attributes that start with "@bind-" and specifies six different
         // parameters applicable for those attributes (":format", ":event", ":culture", ":get", ":set", ":after")
-        var indexerDescriptors = CollectIndexerDescriptors(descriptorsForTag, context);
-
-        foreach (var descriptor in descriptorsForTag)
+        var indexerAttributes = new MemoryBuilder<BoundAttributeDescriptor>(initialCapacity: 8, clearArray: true);
+        try
         {
-            foreach (var attributeDescriptor in descriptor.BoundAttributes)
+            CollectIndexerDescriptors(tagHelpersForTag, completionContext, ref indexerAttributes);
+
+            foreach (var tagHelper in tagHelpersForTag)
             {
-                if (!attributeDescriptor.IsDirectiveAttribute)
+                foreach (var attribute in tagHelper.BoundAttributes)
                 {
-                    // We don't care about non-directive attributes
-                    continue;
+                    if (attribute.IsDirectiveAttribute)
+                    {
+                        AddAttributeNameCompletions(attribute, completionContext, attributeCompletions);
+                        AddParameterNameCompletions(attribute, indexerAttributes.AsMemory().Span, completionContext, attributeCompletions);
+                    }
                 }
-
-                AddAttributeNameCompletions(descriptor, attributeDescriptor, context, attributeCompletions);
-                AddParameterNameCompletions(descriptor, attributeDescriptor, indexerDescriptors, context, attributeCompletions);
             }
-        }
 
-        // Use the mapping populated above to create completion items
-        return CreateCompletionItems(context, attributeCompletions);
+            // Use the mapping populated above to create completion items
+            return CreateCompletionItems(completionContext, attributeCompletions);
+        }
+        finally
+        {
+            indexerAttributes.Dispose();
+        }
     }
 
-    private static ImmutableArray<(BoundAttributeDescriptor, string)> CollectIndexerDescriptors(
-        ImmutableArray<TagHelperDescriptor> descriptorsForTag,
-        DirectiveAttributeCompletionContext context)
+    private static void CollectIndexerDescriptors(
+        TagHelperCollection tagHelpersForTag,
+        DirectiveAttributeCompletionContext completionContext,
+        ref MemoryBuilder<BoundAttributeDescriptor> builder)
     {
-        if (context.InParameterName)
+        if (completionContext.InParameterName)
         {
             // No need to calculate the indexers When in a parameter name
-            return [];
+            return;
         }
 
-        using var allIndexers = new PooledArrayBuilder<(BoundAttributeDescriptor, string)>();
-
-        foreach (var descriptor in descriptorsForTag)
+        foreach (var tagHelper in tagHelpersForTag)
         {
-            foreach (var attributeDescriptor in descriptor.BoundAttributes)
+            foreach (var attribute in tagHelper.BoundAttributes)
             {
-                if (!attributeDescriptor.IsDirectiveAttribute)
+                if (attribute.IsDirectiveAttribute && !attribute.IndexerNamePrefix.IsNullOrEmpty())
                 {
-                    // We don't care about non-directive attributes
-                    continue;
-                }
-
-                if (!attributeDescriptor.IndexerNamePrefix.IsNullOrEmpty())
-                {
-                    allIndexers.Add((attributeDescriptor, descriptor.TypeName));
+                    builder.Append(attribute);
                 }
             }
         }
-
-        return allIndexers.ToImmutableAndClear();
     }
 
     private static void AddAttributeNameCompletions(
-        TagHelperDescriptor descriptor,
-        BoundAttributeDescriptor attributeDescriptor,
-        DirectiveAttributeCompletionContext context,
-        Dictionary<string, (ImmutableArray<BoundAttributeDescriptionInfo>, ImmutableArray<RazorCommitCharacter>, RazorCompletionItemKind kind)> attributeCompletions)
+        BoundAttributeDescriptor attribute,
+        DirectiveAttributeCompletionContext completionContext,
+        Dictionary<string, AttributeCompletionDetails> attributeCompletions)
     {
-        if (!context.InAttributeName)
+        if (!completionContext.InAttributeName)
         {
             // Only add attribute name completions when in an attribute name context
             return;
         }
 
-        var isIndexer = context.SelectedAttributeName.EndsWith("...", StringComparison.Ordinal);
-        var descriptionInfo = BoundAttributeDescriptionInfo.From(attributeDescriptor, isIndexer, descriptor.TypeName);
+        var isIndexer = completionContext.SelectedAttributeName.EndsWith(Ellipsis, StringComparison.Ordinal);
+        var descriptionInfo = BoundAttributeDescriptionInfo.From(attribute, isIndexer, attribute.Parent.TypeName);
 
-        if (!TryAddCompletion(attributeDescriptor.Name, descriptionInfo, descriptor, context, RazorCompletionItemKind.DirectiveAttribute, attributeCompletions) && attributeDescriptor.Parameters.Length > 0)
+        var tagHelper = attribute.Parent;
+
+        if (!TryAddAttributeCompletion(attribute.Name, descriptionInfo, tagHelper, completionContext, attributeCompletions) &&
+            attribute.Parameters.Length > 0)
         {
             // This attribute has parameters and the base attribute name (@bind) is already satisfied. We need to check if there are any valid
             // parameters left to be provided, if so, we need to still represent the base attribute name in the completion list.
 
-            foreach (var parameterDescriptor in attributeDescriptor.Parameters)
+            foreach (var parameter in attribute.Parameters)
             {
-                if (!context.ExistingAttributes.Any(name => TagHelperMatchingConventions.SatisfiesBoundAttributeWithParameter(parameterDescriptor, name, attributeDescriptor)))
+                if (!completionContext.AlreadySatisfiesParameter(parameter, attribute))
                 {
                     // This bound attribute parameter has not had a completion entry added for it, re-represent the base attribute name in the completion list
-                    AddCompletion(attributeDescriptor.Name, descriptionInfo, descriptor, context, RazorCompletionItemKind.DirectiveAttribute, attributeCompletions);
+                    AddAttributeCompletion(attribute.Name, descriptionInfo, tagHelper, completionContext, attributeCompletions);
                     break;
                 }
             }
         }
 
-        if (!attributeDescriptor.IndexerNamePrefix.IsNullOrEmpty())
+        if (!attribute.IndexerNamePrefix.IsNullOrEmpty())
         {
-            TryAddCompletion(attributeDescriptor.IndexerNamePrefix + "...", descriptionInfo, descriptor, context, RazorCompletionItemKind.DirectiveAttribute, attributeCompletions);
+            TryAddAttributeCompletion(
+                attribute.IndexerNamePrefix + Ellipsis, descriptionInfo, tagHelper, completionContext, attributeCompletions);
         }
     }
 
     private static void AddParameterNameCompletions(
-        TagHelperDescriptor descriptor,
-        BoundAttributeDescriptor attributeDescriptor,
-        ImmutableArray<(BoundAttributeDescriptor, string)> indexerDescriptors,
-        DirectiveAttributeCompletionContext context,
-        Dictionary<string, (ImmutableArray<BoundAttributeDescriptionInfo>, ImmutableArray<RazorCommitCharacter>, RazorCompletionItemKind)> attributeCompletions)
+        BoundAttributeDescriptor attribute,
+        ReadOnlySpan<BoundAttributeDescriptor> indexerAttributes,
+        DirectiveAttributeCompletionContext completionContext,
+        Dictionary<string, AttributeCompletionDetails> attributeCompletions)
     {
-        if (context.InAttributeName && !attributeDescriptor.IndexerNamePrefix.IsNullOrEmpty())
+        if (completionContext.InAttributeName && !attribute.IndexerNamePrefix.IsNullOrEmpty())
         {
             // Don't add parameters on indexers in attribute name contexts
             return;
         }
-        else if (context.InParameterName && !TagHelperMatchingConventions.CanSatisfyBoundAttribute(context.SelectedAttributeName, attributeDescriptor))
+
+        if (completionContext.InParameterName && !completionContext.CanSatisfyAttribute(attribute))
         {
             // Don't add parameters when the selected attribute name can't satisfy the given attribute descriptor in parameter name contexts
             return;
         }
 
         // Add indexer parameter completions first so they display first in completion descriptions.
-        foreach (var (indexerDescriptor, parentTagHelperTypeName) in indexerDescriptors)
+        foreach (var indexerAttribute in indexerAttributes)
         {
-            if (!attributeDescriptor.Name.StartsWith(indexerDescriptor.IndexerNamePrefix!))
+            var indexerNamePrefix = indexerAttribute.IndexerNamePrefix.AssumeNotNull();
+
+            if (!attribute.Name.StartsWith(indexerNamePrefix))
             {
                 continue;
             }
 
-            AddCompletionsForParameters(indexerDescriptor.Parameters, descriptor, attributeDescriptor, parentTagHelperTypeName, context, attributeCompletions);
+            AddCompletionsForParameters(attribute, indexerAttribute.Parameters, completionContext, attributeCompletions);
         }
 
         // Then add regular parameter completions
-        AddCompletionsForParameters(attributeDescriptor.Parameters, descriptor, attributeDescriptor, descriptor.TypeName, context, attributeCompletions);
+        AddCompletionsForParameters(attribute, attribute.Parameters, completionContext, attributeCompletions);
 
         return;
 
         static void AddCompletionsForParameters(
-            ImmutableArray<BoundAttributeParameterDescriptor> parameterDescriptors,
-            TagHelperDescriptor descriptor,
-            BoundAttributeDescriptor attributeDescriptor,
-            string parentTagHelperTypeName,
-            DirectiveAttributeCompletionContext context,
-            Dictionary<string, (ImmutableArray<BoundAttributeDescriptionInfo>, ImmutableArray<RazorCommitCharacter>, RazorCompletionItemKind)> attributeCompletions)
+            BoundAttributeDescriptor attribute,
+            ImmutableArray<BoundAttributeParameterDescriptor> parameters,
+            DirectiveAttributeCompletionContext completionContext,
+            Dictionary<string, AttributeCompletionDetails> attributeCompletions)
         {
-            foreach (var parameterDescriptor in parameterDescriptors)
+            var tagHelper = attribute.Parent;
+
+            foreach (var parameter in parameters)
             {
-                if (context.ExistingAttributes.Any(
-                    (parameterDescriptor, attributeDescriptor),
-                    static (name, arg) =>
-                        TagHelperMatchingConventions.SatisfiesBoundAttributeWithParameter(arg.parameterDescriptor, name, arg.attributeDescriptor)))
+                if (completionContext.AlreadySatisfiesParameter(parameter, attribute))
                 {
                     // There's already an existing attribute that satisfies this parameter, don't show it in the completion list.
                     continue;
                 }
 
-                var descriptionInfo = BoundAttributeDescriptionInfo.From(parameterDescriptor, parentTagHelperTypeName);
-                var displayName = context.InParameterName
-                    ? parameterDescriptor.Name
-                    : $"{attributeDescriptor.Name}:{parameterDescriptor.Name}";
+                var displayName = completionContext.InParameterName
+                    ? parameter.Name
+                    : $"{attribute.Name}:{parameter.Name}";
 
-                AddCompletion(displayName, descriptionInfo, descriptor, context, RazorCompletionItemKind.DirectiveAttributeParameter, attributeCompletions);
+                AddParameterCompletion(
+                    displayName,
+                    descriptionInfo: BoundAttributeDescriptionInfo.From(parameter),
+                    tagHelper,
+                    completionContext,
+                    attributeCompletions);
             }
         }
     }
 
-    private static ImmutableArray<RazorCompletionItem> CreateCompletionItems(DirectiveAttributeCompletionContext context, Dictionary<string, (ImmutableArray<BoundAttributeDescriptionInfo>, ImmutableArray<RazorCommitCharacter>, RazorCompletionItemKind kind)> attributeCompletions)
+    private static ImmutableArray<RazorCompletionItem> CreateCompletionItems(
+        DirectiveAttributeCompletionContext completionContext,
+        Dictionary<string, AttributeCompletionDetails> attributeCompletions)
     {
         using var completionItems = new PooledArrayBuilder<RazorCompletionItem>(capacity: attributeCompletions.Count);
 
-        foreach (var (displayText, (attributeDescriptions, commitCharacters, kind)) in attributeCompletions)
+        foreach (var (displayText, (kind, descriptions, commitCharacters)) in attributeCompletions)
         {
-            var originalInsertTextMemory = displayText.AsMemory();
+            var isIndexer = displayText.EndsWith(Ellipsis, StringComparison.Ordinal);
+            var isSnippet = !isIndexer && completionContext.UseSnippets;
+            var autoInsertAttributeQuotes = completionContext.Options.AutoInsertAttributeQuotes;
 
-            // Strip off the @ from the insertion text. This change is here to align the insertion text with the
-            // completion hooks into VS and VSCode. Basically, completion triggers when `@` is typed so we don't
-            // want to insert `@bind` because `@` already exists.
-            var insertTextMemory = originalInsertTextMemory.Span.StartsWith('@')
-                ? originalInsertTextMemory[1..]
-                : originalInsertTextMemory;
+            var insertText = ComputeInsertText(displayText, isIndexer, isSnippet, autoInsertAttributeQuotes);
 
-            var isSnippet = false;
-            string insertText;
+            Debug.Assert(kind is RazorCompletionItemKind.DirectiveAttribute or RazorCompletionItemKind.DirectiveAttributeParameter);
 
-            // Indexer attribute, we don't want to insert with the triple dot.
-            if (MemoryExtensions.EndsWith(insertTextMemory.Span, "...".AsSpan()))
-            {
-                insertText = insertTextMemory[..^3].ToString();
-            }
-            else if (context.UseSnippets)
-            {
-                var suffixText = context.Options.AutoInsertAttributeQuotes ? s_quotedAttributeValueSnippet : s_unquotedAttributeValueSnippet;
+            var razorCompletionItem = kind == RazorCompletionItemKind.DirectiveAttribute
+                ? RazorCompletionItem.CreateDirectiveAttribute(displayText, insertText, descriptionInfo: new(descriptions), commitCharacters, isSnippet)
+                : RazorCompletionItem.CreateDirectiveAttributeParameter(displayText, insertText, descriptionInfo: new(descriptions), commitCharacters, isSnippet);
 
-                // We are trying for snippet text only for non-indexer attributes, e.g. *not* something like "@bind-..."
-                insertText = string.Create(
-                    length: insertTextMemory.Length + suffixText.Length,
-                    state: (insertTextMemory, suffixText),
-                    static (desination, state) =>
-                    {
-                        var (baseTextMemory, suffixText) = state;
+            completionItems.Add(razorCompletionItem);
+        }
 
-                        baseTextMemory.Span.CopyTo(desination);
-                        suffixText.AsSpan().CopyTo(desination[baseTextMemory.Length..]);
-                    });
+        return completionItems.ToImmutableAndClear();
+    }
 
-                isSnippet = true;
-            }
-            else
-            {
-                // Don't create another string unnecessarily, even though ReadOnlySpan.ToString() special-cases the string to avoid allocation
-                insertText = insertTextMemory.Span == originalInsertTextMemory.Span ? displayText : insertTextMemory.ToString();
-            }
+    private static string ComputeInsertText(string displayText, bool isIndexer, bool isSnippet, bool autoInsertAttributeQuotes)
+    {
+        var originalInsertText = displayText.AsMemory();
 
-            Debug.Assert(kind is RazorCompletionItemKind.DirectiveAttribute or RazorCompletionItemKind.DirectiveAttributeParameter);
-            var razorCompletionItem = (kind == RazorCompletionItemKind.DirectiveAttribute)
-                ? RazorCompletionItem.CreateDirectiveAttribute(displayText, insertText, descriptionInfo: new(attributeDescriptions), commitCharacters, isSnippet)
-                : RazorCompletionItem.CreateDirectiveAttributeParameter(displayText, insertText, descriptionInfo: new(attributeDescriptions), commitCharacters, isSnippet);
+        // Strip off the @ from the insertion text. This change is here to align the insertion text with the
+        // completion hooks into VS and VSCode. Basically, completion triggers when `@` is typed so we don't
+        // want to insert `@bind` because `@` already exists.
+        var insertText = originalInsertText.Span.StartsWith('@')
+            ? originalInsertText[1..]
+            : originalInsertText;
 
-            completionItems.Add(razorCompletionItem);
+        // Indexer attribute, we don't want to insert with the triple dot.
+        if (isIndexer)
+        {
+            Debug.Assert(insertText.Span.EndsWith(Ellipsis, StringComparison.Ordinal));
+            return insertText[..^3].ToString();
         }
 
-        return completionItems.ToImmutableAndClear();
+        if (isSnippet)
+        {
+            var suffixText = autoInsertAttributeQuotes
+                ? QuotedAttributeValueSnippetSuffix
+                : UnquotedAttributeValueSnippetSuffix;
+
+            // We are trying for snippet text only for non-indexer attributes, e.g. *not* something like "@bind-..."
+            return string.Create(
+                length: insertText.Length + suffixText.Length,
+                state: (insertText, suffixText),
+                static (destination, state) =>
+                {
+                    var (insertText, suffixText) = state;
+
+                    insertText.Span.CopyTo(destination);
+                    suffixText.AsSpan().CopyTo(destination[insertText.Length..]);
+                });
+        }
+
+        // Don't create another string unnecessarily, even though ReadOnlySpan.ToString() special-cases
+        // the string to avoid allocation.
+        return insertText.Span == originalInsertText.Span
+            ? displayText
+            : insertText.ToString();
     }
 
-    private static bool TryAddCompletion(
+    private static bool TryAddAttributeCompletion(
         string attributeName,
         BoundAttributeDescriptionInfo descriptionInfo,
-        TagHelperDescriptor tagHelperDescriptor,
-        DirectiveAttributeCompletionContext context,
-        RazorCompletionItemKind kind,
-        Dictionary<string, (ImmutableArray<BoundAttributeDescriptionInfo>, ImmutableArray<RazorCommitCharacter>, RazorCompletionItemKind kind)> attributeCompletions)
+        TagHelperDescriptor tagHelper,
+        DirectiveAttributeCompletionContext completionContext,
+        Dictionary<string, AttributeCompletionDetails> attributeCompletions)
     {
-        if (context.SelectedAttributeName != attributeName &&
-            context.ExistingAttributes.Any(attributeName, static (name, attributeName) => name == attributeName))
+        if (completionContext.SelectedAttributeName != attributeName &&
+            completionContext.ExistingAttributes.Contains(attributeName))
         {
             // Attribute is already present on this element and it is not the selected attribute.
             // It shouldn't exist in the completion list.
             return false;
         }
 
-        AddCompletion(attributeName, descriptionInfo, tagHelperDescriptor, context, kind, attributeCompletions);
+        AddAttributeCompletion(attributeName, descriptionInfo, tagHelper, completionContext, attributeCompletions);
         return true;
     }
 
-    private static void AddCompletion(
+    private static void AddAttributeCompletion(
         string attributeName,
         BoundAttributeDescriptionInfo descriptionInfo,
-        TagHelperDescriptor tagHelperDescriptor,
-        DirectiveAttributeCompletionContext context,
+        TagHelperDescriptor tagHelper,
+        DirectiveAttributeCompletionContext completionContext,
+        Dictionary<string, AttributeCompletionDetails> attributeCompletions)
+        => AddCompletion(RazorCompletionItemKind.DirectiveAttribute,
+            attributeName, descriptionInfo, tagHelper, completionContext, attributeCompletions);
+
+    private static void AddParameterCompletion(
+        string attributeName,
+        BoundAttributeDescriptionInfo descriptionInfo,
+        TagHelperDescriptor tagHelper,
+        DirectiveAttributeCompletionContext completionContext,
+        Dictionary<string, AttributeCompletionDetails> attributeCompletions)
+        => AddCompletion(RazorCompletionItemKind.DirectiveAttributeParameter,
+            attributeName, descriptionInfo, tagHelper, completionContext, attributeCompletions);
+
+    private static void AddCompletion(
         RazorCompletionItemKind kind,
-        Dictionary<string, (ImmutableArray<BoundAttributeDescriptionInfo>, ImmutableArray<RazorCommitCharacter>, RazorCompletionItemKind kind)> attributeCompletions)
+        string attributeName,
+        BoundAttributeDescriptionInfo descriptionInfo,
+        TagHelperDescriptor tagHelper,
+        DirectiveAttributeCompletionContext completionContext,
+        Dictionary<string, AttributeCompletionDetails> attributeCompletions)
     {
-        if (!attributeCompletions.TryGetValue(attributeName, out var attributeDetails))
-        {
-            attributeDetails = ([], [], RazorCompletionItemKind.Attribute);
-        }
+        ImmutableArray<BoundAttributeDescriptionInfo> descriptions;
+        ImmutableArray<RazorCommitCharacter> commitCharacters;
 
-        (var attributeDescriptions, var commitCharacters, _) = attributeDetails;
+        if (attributeCompletions.TryGetValue(attributeName, out var existingDetails))
+        {
+            (descriptions, commitCharacters) = existingDetails;
 
-        if (!attributeDescriptions.Contains(descriptionInfo))
+            if (!descriptions.Contains(descriptionInfo))
+            {
+                descriptions = descriptions.Add(descriptionInfo);
+            }
+        }
+        else
         {
-            attributeDescriptions = attributeDescriptions.Add(descriptionInfo);
+            descriptions = [descriptionInfo];
+            commitCharacters = [];
         }
 
         // Verify not an indexer attribute, as those don't commit with standard chars
-        if (!attributeName.EndsWith("...", StringComparison.Ordinal))
+        if (!attributeName.EndsWith(Ellipsis, StringComparison.Ordinal))
         {
-            var isEqualCommitChar = commitCharacters.Any(static c => c.Character == "=");
-            var isSpaceCommitChar = commitCharacters.Any(static c => c.Character == " ");
-
-            // We don't add "=" as a commit character when using VSCode trigger characters.
-            isEqualCommitChar |= !context.Options.UseVsCodeCompletionCommitCharacters;
-
-            foreach (var boundAttribute in tagHelperDescriptor.BoundAttributes)
-            {
-                isSpaceCommitChar |= boundAttribute.IsBooleanProperty;
+            // We always add "=" as a commit character in Visual Studio.
+            var useEqualsCommit = !completionContext.Options.UseVsCodeCompletionCommitCharacters ||
+                                  commitCharacters.Any(static c => c.Character == "=");
 
-                if (isSpaceCommitChar)
-                {
-                    break;
-                }
-            }
+            var useSpaceCommit = commitCharacters.Any(static c => c.Character == " ") ||
+                                 tagHelper.BoundAttributes.Any(static a => a.IsBooleanProperty);
 
-            // Determine if we have a common commit character set
-            commitCharacters = (isEqualCommitChar, isSpaceCommitChar, context.UseSnippets) switch
-            {
-                (true, false, false) => s_equalsCommitCharacters,
-                (true, false, true) => s_snippetEqualsCommitCharacters,
-                _ => []
-            };
-
-            if (commitCharacters.IsEmpty)
-            {
-                if (isEqualCommitChar)
-                {
-                    commitCharacters = commitCharacters.Add(new("=", Insert: !context.UseSnippets));
-                }
-
-                if (isSpaceCommitChar)
-                {
-                    commitCharacters = commitCharacters.Add(new(" "));
-                }
-            }
+            commitCharacters = DefaultCommitCharacters.Get(useEqualsCommit, useSpaceCommit, completionContext.UseSnippets);
         }
 
-        attributeCompletions[attributeName] = (attributeDescriptions, commitCharacters, kind);
+        attributeCompletions[attributeName] = new(kind, descriptions, commitCharacters);
     }
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionProvider.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionProvider.cs
index 11ec80c3498..b3c53185b15 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionProvider.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionProvider.cs
@@ -114,7 +114,7 @@ private ImmutableArray<RazorCompletionItem> GetAttributeCompletions(
         RazorCompletionOptions options)
     {
         var ancestors = containingAttribute.Parent.Ancestors();
-        var nonDirectiveAttributeTagHelpers = tagHelperDocumentContext.TagHelpers.WhereAsArray(
+        var nonDirectiveAttributeTagHelpers = tagHelperDocumentContext.TagHelpers.Where(
             static tagHelper => !tagHelper.BoundAttributes.Any(static attribute => attribute.IsDirectiveAttribute));
         var filteredContext = TagHelperDocumentContext.Create(tagHelperDocumentContext.Prefix, nonDirectiveAttributeTagHelpers);
         var (ancestorTagName, ancestorIsTagHelper) = TagHelperFacts.GetNearestAncestorTagInfo(ancestors);
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionService.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionService.cs
index 35688f57f74..45853c1e04a 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionService.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Completion/TagHelperCompletionService.cs
@@ -6,6 +6,7 @@
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
+using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.CodeAnalysis.Razor.Workspaces;
@@ -15,6 +16,9 @@ namespace Microsoft.CodeAnalysis.Razor.Completion;
 
 internal class TagHelperCompletionService : ITagHelperCompletionService
 {
+    private static readonly HashSetPool<TagHelperDescriptor> s_shortNameSetPool =
+        HashSetPool<TagHelperDescriptor>.Create(ShortNameToFullyQualifiedComparer.Instance);
+
     private static readonly HashSet<TagHelperDescriptor> s_emptyHashSet = new();
 
     // This API attempts to understand a users context as they're typing in a Razor file to provide TagHelper based attribute IntelliSense.
@@ -29,10 +33,7 @@ internal class TagHelperCompletionService : ITagHelperCompletionService
     // BoundAttributeDescriptor. By doing this a user can see what C# type a TagHelper expects for the attribute.
     public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionContext completionContext)
     {
-        if (completionContext is null)
-        {
-            throw new ArgumentNullException(nameof(completionContext));
-        }
+        ArgHelper.ThrowIfNull(completionContext);
 
         var attributeCompletions = completionContext.ExistingCompletions.ToDictionary(
             completion => completion,
@@ -40,8 +41,8 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
             StringComparer.OrdinalIgnoreCase);
 
         var documentContext = completionContext.DocumentContext;
-        var descriptorsForTag = TagHelperFacts.GetTagHelpersGivenTag(documentContext, completionContext.CurrentTagName, completionContext.CurrentParentTagName);
-        if (descriptorsForTag.Length == 0)
+        var tagHelpersForTag = TagHelperFacts.GetTagHelpersGivenTag(documentContext, completionContext.CurrentTagName, completionContext.CurrentParentTagName);
+        if (tagHelpersForTag.IsEmpty)
         {
             // If the current tag has no possible descriptors then we can't have any additional attributes.
             return AttributeCompletionResult.Create(attributeCompletions);
@@ -59,9 +60,9 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
 
         using var _ = HashSetPool<TagHelperDescriptor>.GetPooledObject(out var applicableDescriptors);
 
-        if (applicableTagHelperBinding is { Descriptors: var descriptors })
+        if (applicableTagHelperBinding is { TagHelpers: var tagHelpers })
         {
-            applicableDescriptors.UnionWith(descriptors);
+            applicableDescriptors.UnionWith(tagHelpers);
         }
 
         var unprefixedTagName = completionContext.CurrentTagName[prefix.Length..];
@@ -73,11 +74,11 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
             attributeCompletions.Clear();
         }
 
-        foreach (var descriptor in descriptorsForTag)
+        foreach (var tagHelper in tagHelpersForTag)
         {
-            if (applicableDescriptors.Contains(descriptor))
+            if (applicableDescriptors.Contains(tagHelper))
             {
-                foreach (var attributeDescriptor in descriptor.BoundAttributes)
+                foreach (var attributeDescriptor in tagHelper.BoundAttributes)
                 {
                     if (!attributeDescriptor.Name.IsNullOrEmpty())
                     {
@@ -93,7 +94,7 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
             else
             {
                 var htmlNameToBoundAttribute = new Dictionary<string, BoundAttributeDescriptor>(StringComparer.OrdinalIgnoreCase);
-                foreach (var attributeDescriptor in descriptor.BoundAttributes)
+                foreach (var attributeDescriptor in tagHelper.BoundAttributes)
                 {
                     if (attributeDescriptor.Name != null)
                     {
@@ -106,7 +107,7 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
                     }
                 }
 
-                foreach (var rule in descriptor.TagMatchingRules)
+                foreach (var rule in tagHelper.TagMatchingRules)
                 {
                     foreach (var requiredAttribute in rule.Attributes)
                     {
@@ -152,10 +153,7 @@ void UpdateCompletions(string attributeName, BoundAttributeDescriptor? possibleD
 
     public ElementCompletionResult GetElementCompletions(ElementCompletionContext completionContext)
     {
-        if (completionContext is null)
-        {
-            throw new ArgumentNullException(nameof(completionContext));
-        }
+        ArgHelper.ThrowIfNull(completionContext);
 
         var elementCompletions = new Dictionary<string, HashSet<TagHelperDescriptor>>(StringComparer.Ordinal);
 
@@ -170,11 +168,16 @@ public ElementCompletionResult GetElementCompletions(ElementCompletionContext co
 
         var tagAttributes = completionContext.Attributes;
 
-        var catchAllDescriptors = new HashSet<TagHelperDescriptor>();
+        var catchAllTagHelpers = new HashSet<TagHelperDescriptor>();
         var prefix = completionContext.DocumentContext.Prefix ?? string.Empty;
-        var possibleChildDescriptors = TagHelperFacts.GetTagHelpersGivenParent(completionContext.DocumentContext, completionContext.ContainingParentTagName);
-        possibleChildDescriptors = FilterFullyQualifiedCompletions(possibleChildDescriptors);
-        foreach (var possibleDescriptor in possibleChildDescriptors)
+
+        var possibleChildTagHelpers = TagHelperFacts.GetTagHelpersGivenParent(
+            completionContext.DocumentContext,
+            completionContext.ContainingParentTagName);
+
+        possibleChildTagHelpers = FilterFullyQualifiedTagHelpers(possibleChildTagHelpers);
+
+        foreach (var possibleDescriptor in possibleChildTagHelpers)
         {
             var addRuleCompletions = false;
             var checkAttributeRules = true;
@@ -182,14 +185,14 @@ public ElementCompletionResult GetElementCompletions(ElementCompletionContext co
 
             foreach (var rule in possibleDescriptor.TagMatchingRules)
             {
-                if (!TagHelperMatchingConventions.SatisfiesParentTag(rule, completionContext.ContainingParentTagName.AsSpanOrDefault()))
+                if (!TagHelperMatchingConventions.SatisfiesParentTag(rule, completionContext.ContainingParentTagName.AsSpan()))
                 {
                     continue;
                 }
 
                 if (rule.TagName == TagHelperMatchingConventions.ElementCatchAllName)
                 {
-                    catchAllDescriptors.Add(possibleDescriptor);
+                    catchAllTagHelpers.Add(possibleDescriptor);
                 }
                 else if (elementCompletions.ContainsKey(rule.TagName))
                 {
@@ -233,19 +236,16 @@ public ElementCompletionResult GetElementCompletions(ElementCompletionContext co
 
         // We needed to track all catch-alls and update their completions after all other completions have been completed.
         // This way, any TagHelper added completions will also have catch-alls listed under their entries.
-        foreach (var catchAllDescriptor in catchAllDescriptors)
+        foreach (var catchAllTagHelper in catchAllTagHelpers)
         {
-            foreach (var kvp in elementCompletions)
+            foreach (var (completionTagName, completionTagHelpers) in elementCompletions)
             {
-                var completionTagName = kvp.Key;
-                var tagHelperDescriptors = kvp.Value;
-
-                if (tagHelperDescriptors.Count > 0 ||
+                if (completionTagHelpers.Count > 0 ||
                     (!string.IsNullOrEmpty(prefix) && completionTagName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)))
                 {
                     // The current completion either has other TagHelper's associated with it or is prefixed with a non-empty
                     // TagHelper prefix.
-                    UpdateCompletions(completionTagName, catchAllDescriptor, elementCompletions, tagHelperDescriptors);
+                    UpdateCompletions(completionTagName, catchAllTagHelper, elementCompletions, completionTagHelpers);
                 }
             }
         }
@@ -303,17 +303,17 @@ private void AddAllowedChildrenCompletions(
             return;
         }
 
-        foreach (var descriptor in binding.Descriptors)
+        foreach (var tagHelper in binding.TagHelpers)
         {
-            foreach (var childTag in descriptor.AllowedChildTags)
+            foreach (var childTag in tagHelper.AllowedChildTags)
             {
                 var prefixedName = string.Concat(prefix, childTag.Name);
-                var descriptors = TagHelperFacts.GetTagHelpersGivenTag(
+                var tagHelpersForTag = TagHelperFacts.GetTagHelpersGivenTag(
                     completionContext.DocumentContext,
                     prefixedName,
                     completionContext.ContainingParentTagName);
 
-                if (descriptors.Length == 0)
+                if (tagHelpersForTag.IsEmpty)
                 {
                     if (!elementCompletions.ContainsKey(prefixedName))
                     {
@@ -329,47 +329,33 @@ private void AddAllowedChildrenCompletions(
                     elementCompletions[prefixedName] = existingRuleDescriptors;
                 }
 
-                existingRuleDescriptors.AddRange(descriptors);
+                existingRuleDescriptors.UnionWith(tagHelpersForTag);
             }
         }
     }
 
-    private static ImmutableArray<TagHelperDescriptor> FilterFullyQualifiedCompletions(ImmutableArray<TagHelperDescriptor> possibleChildDescriptors)
+    private static TagHelperCollection FilterFullyQualifiedTagHelpers(TagHelperCollection tagHelpers)
     {
-        // Iterate once through the list to tease apart fully qualified and short name TagHelpers
-        using var fullyQualifiedTagHelpers = new PooledArrayBuilder<TagHelperDescriptor>();
-        var shortNameTagHelpers = new HashSet<TagHelperDescriptor>(ShortNameToFullyQualifiedComparer.Instance);
-
-        foreach (var descriptor in possibleChildDescriptors)
-        {
-            if (descriptor.IsFullyQualifiedNameMatch)
-            {
-                fullyQualifiedTagHelpers.Add(descriptor);
-            }
-            else
-            {
-                shortNameTagHelpers.Add(descriptor);
-            }
-        }
+        // We want to filter 'tagHelpers' and remove any tag helpers that require a fully-qualified name match
+        // but have a short name match present.
 
-        // Re-combine the short named & fully qualified TagHelpers but filter out any fully qualified TagHelpers that have a short
-        // named representation already.
-        using var filteredList = new PooledArrayBuilder<TagHelperDescriptor>(capacity: shortNameTagHelpers.Count);
-        filteredList.AddRange(shortNameTagHelpers);
+        // First, collect all "short name" tag helpers, i.e. those that do not require a fully qualified name match.
+        using var _ = s_shortNameSetPool.GetPooledObject(out var shortNameSet);
 
-        foreach (var fullyQualifiedTagHelper in fullyQualifiedTagHelpers)
+        foreach (var tagHelper in tagHelpers)
         {
-            if (!shortNameTagHelpers.Contains(fullyQualifiedTagHelper))
+            if (!tagHelper.IsFullyQualifiedNameMatch)
             {
-                // Unimported completion item that isn't represented in a short named form.
-                filteredList.Add(fullyQualifiedTagHelper);
-            }
-            else
-            {
-                // There's already a shortname variant of this item, don't include it.
+                shortNameSet.Add(tagHelper);
             }
         }
 
-        return filteredList.ToImmutableAndClear();
+        return tagHelpers.Where(shortNameSet, static (tagHelper, shortNameSet) =>
+        {
+            // We want to keep tag helpers that either:
+            // 1. Do not require a fully qualified name match (i.e., short name tag helpers).
+            // 2. Are fully qualified tag helpers that do not have a corresponding short name tag helper.
+            return !tagHelper.IsFullyQualifiedNameMatch || !shortNameSet.Contains(tagHelper);
+        });
     }
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Extensions/ProjectExtensions.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Extensions/ProjectExtensions.cs
index 967f55a17d7..d7319c698d5 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Extensions/ProjectExtensions.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Extensions/ProjectExtensions.cs
@@ -31,7 +31,7 @@ internal static class ProjectExtensions
     /// <remarks>
     ///  A telemetry event will be reported to <paramref name="telemetryReporter"/>.
     /// </remarks>
-    public static async ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
+    public static async ValueTask<TagHelperCollection> GetTagHelpersAsync(
         this Project project,
         RazorProjectEngine projectEngine,
         ITelemetryReporter telemetryReporter,
@@ -50,11 +50,11 @@ public static async ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpers
             return [];
         }
 
-        using var pooledHashSet = HashSetPool<TagHelperDescriptor>.GetPooledObject(out var results);
+        using var builder = new TagHelperCollection.Builder();
         using var pooledWatch = StopwatchPool.GetPooledObject(out var watch);
         using var pooledSpan = ArrayPool<Property>.Shared.GetPooledArraySpan(minimumLength: providers.Length, out var properties);
 
-        var context = new TagHelperDescriptorProviderContext(compilation, results)
+        var context = new TagHelperDescriptorProviderContext(compilation, builder)
         {
             ExcludeHidden = true,
             IncludeDocumentation = true
@@ -74,7 +74,7 @@ public static async ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpers
 
         telemetryReporter.ReportEvent(GetTagHelpersEventName, Severity.Normal, properties);
 
-        return [.. results];
+        return builder.ToCollection();
     }
 
     private static ImmutableArray<ITagHelperDescriptorProvider> GetTagHelperDescriptorProviders(RazorProjectEngine projectEngine)
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/FormattingVisitor.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/FormattingVisitor.cs
index c85e1de6aca..8ea75e5a575 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/FormattingVisitor.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/FormattingVisitor.cs
@@ -242,7 +242,7 @@ public override void VisitMarkupTagHelperElement(MarkupTagHelperElementSyntax no
 
         static bool IsComponentTagHelperNode(MarkupTagHelperElementSyntax node)
         {
-            return node.TagHelperInfo?.BindingResult?.Descriptors is { Length: > 0 } descriptors &&
+            return node.TagHelperInfo.BindingResult.TagHelpers is { Count: > 0 } descriptors &&
                    descriptors.Any(static d => d.IsComponentOrChildContentTagHelper());
         }
 
@@ -271,7 +271,7 @@ static bool ParentHasProperty(MarkupTagHelperElementSyntax parentComponent, stri
             //
             // This code will not count "ChildContent" as causing indentation because its parent
             // has a property called "ChildContent".
-            if (parentComponent.TagHelperInfo?.BindingResult.Descriptors.Any(d => d.BoundAttributes.Any(a => a.Name == propertyName)) ?? false)
+            if (parentComponent.TagHelperInfo.BindingResult.TagHelpers.Any(d => d.BoundAttributes.Any(a => a.Name == propertyName)))
             {
                 return true;
             }
@@ -281,7 +281,7 @@ static bool ParentHasProperty(MarkupTagHelperElementSyntax parentComponent, stri
 
         static bool HasUnspecifiedCascadingTypeParameter(MarkupTagHelperElementSyntax node)
         {
-            if (node.TagHelperInfo?.BindingResult?.Descriptors is not { Length: > 0 } descriptors)
+            if (node.TagHelperInfo.BindingResult.TagHelpers is not { Count: > 0 } descriptors)
             {
                 return false;
             }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/Passes/CSharpFormattingPass.CSharpDocumentGenerator.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/Passes/CSharpFormattingPass.CSharpDocumentGenerator.cs
index f97f95fb86f..e181ca93095 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/Passes/CSharpFormattingPass.CSharpDocumentGenerator.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/Passes/CSharpFormattingPass.CSharpDocumentGenerator.cs
@@ -261,7 +261,7 @@ private void AddAdditionalLineFormattingContent(StringBuilder additionalLinesBui
                 // what the user expects.
                 if (node is { Parent.Parent: MarkupTagHelperAttributeSyntax attribute } &&
                     attribute is { Parent.Parent: MarkupTagHelperElementSyntax element } &&
-                    element.TagHelperInfo.BindingResult.Descriptors is [{ } descriptor] &&
+                    element.TagHelperInfo.BindingResult.TagHelpers is [{ } descriptor] &&
                     descriptor.IsGenericTypedComponent() &&
                     descriptor.BoundAttributes.FirstOrDefault(d => d.Name == attribute.TagHelperAttributeInfo.Name) is { } boundAttribute &&
                     boundAttribute.IsTypeParameterProperty())
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/GoToDefinition/RazorComponentDefinitionHelpers.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/GoToDefinition/RazorComponentDefinitionHelpers.cs
index d76a83c5882..c727a4b945f 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/GoToDefinition/RazorComponentDefinitionHelpers.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/GoToDefinition/RazorComponentDefinitionHelpers.cs
@@ -71,7 +71,7 @@ public static bool TryGetBoundTagHelpers(
 
         using var descriptorsBuilder = new PooledArrayBuilder<BoundTagHelperResult>();
 
-        foreach (var boundTagHelper in binding.Descriptors.Where(d => !d.IsAttributeDescriptor()))
+        foreach (var boundTagHelper in binding.TagHelpers.Where(d => !d.IsAttributeDescriptor()))
         {
             var requireAttributeMatch = false;
             if ((!ignoreComponentAttributes || boundTagHelper.Kind != TagHelperKind.Component) &&
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Hover/HoverFactory.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Hover/HoverFactory.cs
index 57d3a5a9a4f..6dc522198e3 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Hover/HoverFactory.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Hover/HoverFactory.cs
@@ -88,14 +88,14 @@ internal static class HoverFactory
                 return SpecializedTasks.Null<LspHover>();
             }
 
-            Debug.Assert(binding.Descriptors.Any());
+            Debug.Assert(binding.TagHelpers.Any());
 
             var span = containingTagNameToken.GetLinePositionSpan(codeDocument.Source);
 
             var filePath = codeDocument.Source.FilePath.AssumeNotNull();
 
             return ElementInfoToHoverAsync(
-                filePath, binding.Descriptors, span, options, componentAvailabilityService, cancellationToken);
+                filePath, binding.TagHelpers, span, options, componentAvailabilityService, cancellationToken);
         }
 
         if (HtmlFacts.TryGetAttributeInfo(owner, out containingTagNameToken, out _, out var selectedAttributeName, out var selectedAttributeNameLocation, out attributes) &&
@@ -123,7 +123,7 @@ internal static class HoverFactory
                 return SpecializedTasks.Null<LspHover>();
             }
 
-            Debug.Assert(binding.Descriptors.Any());
+            Debug.Assert(binding.TagHelpers.Any());
             var tagHelperAttributes = TagHelperFacts.GetBoundTagHelperAttributes(
                 tagHelperContext,
                 selectedAttributeName.AssumeNotNull(),
@@ -218,7 +218,7 @@ internal static class HoverFactory
 
     private static async Task<LspHover?> ElementInfoToHoverAsync(
         string documentFilePath,
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         LinePositionSpan span,
         HoverDisplayOptions options,
         IComponentAvailabilityService componentAvailabilityService,
@@ -226,7 +226,7 @@ internal static class HoverFactory
     {
         // Filter out attribute descriptors since we're creating an element hover
         var keepAttributeInfo = FileKinds.GetFileKindFromPath(documentFilePath) == RazorFileKind.Legacy;
-        var descriptionInfos = descriptors
+        var descriptionInfos = tagHelpers
             .Where(d => keepAttributeInfo || !d.IsAttributeDescriptor())
             .SelectAsArray(BoundElementDescriptionInfo.From);
         var elementDescriptionInfo = new AggregateBoundElementDescription(descriptionInfos);
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ITagHelperResolver.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ITagHelperResolver.cs
index 3283d3f64d5..b6692c24fb5 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ITagHelperResolver.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ITagHelperResolver.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
@@ -16,7 +15,7 @@ internal interface ITagHelperResolver
     ///  <see cref="Project"/> using the given <see cref="ProjectSnapshot"/> to provide a
     ///  <see cref="RazorProjectEngine"/>.
     /// </summary>
-    ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
+    ValueTask<TagHelperCollection?> GetTagHelpersAsync(
         Project project,
         ProjectSnapshot projectSnapshot,
         CancellationToken cancellationToken);
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/AbstractRazorProjectInfoDriver.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/AbstractRazorProjectInfoDriver.cs
index 229417d73de..abdf0503063 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/AbstractRazorProjectInfoDriver.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/AbstractRazorProjectInfoDriver.cs
@@ -105,7 +105,7 @@ private async ValueTask ProcessBatchAsync(ImmutableArray<Work> items, Cancellati
                 switch (work)
                 {
                     case Update(var projectInfo):
-                        Logger?.LogTrace($"Sending update for {projectInfo.FilePath} with {projectInfo.ProjectWorkspaceState.TagHelpers.Length} TagHelpers");
+                        Logger?.LogTrace($"Sending update for {projectInfo.FilePath} with {projectInfo.ProjectWorkspaceState.TagHelpers.Count} TagHelpers");
                         _latestProjectInfoMap[projectInfo.ProjectKey] = projectInfo;
                         break;
 
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/IProjectSnapshot.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/IProjectSnapshot.cs
index 7763a9f54b8..310c92e2ea0 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/IProjectSnapshot.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/IProjectSnapshot.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 using System.Threading.Tasks;
@@ -31,7 +30,7 @@ internal interface IProjectSnapshot
     string DisplayName { get; }
     LanguageVersion CSharpLanguageVersion { get; }
 
-    ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(CancellationToken cancellationToken);
+    ValueTask<TagHelperCollection> GetTagHelpersAsync(CancellationToken cancellationToken);
 
     bool ContainsDocument(string filePath);
     bool TryGetDocument(string filePath, [NotNullWhen(true)] out IDocumentSnapshot? document);
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Legacy/ILegacyProjectSnapshot.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Legacy/ILegacyProjectSnapshot.cs
index 57ee41e1768..b8b657ed984 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Legacy/ILegacyProjectSnapshot.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Legacy/ILegacyProjectSnapshot.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.CodeAnalysis.CSharp;
 
@@ -21,7 +20,7 @@ internal interface ILegacyProjectSnapshot
 
     string? RootNamespace { get; }
     LanguageVersion CSharpLanguageVersion { get; }
-    ImmutableArray<TagHelperDescriptor> TagHelpers { get; }
+    TagHelperCollection TagHelpers { get; }
 
     RazorProjectEngine GetProjectEngine();
 
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs
index 6ccc250cb9b..60a681a14c5 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectSnapshot.cs
@@ -37,7 +37,7 @@ internal sealed class ProjectSnapshot(ProjectState state) : IProjectSnapshot, IL
 
     public RazorProjectEngine ProjectEngine => _state.ProjectEngine;
 
-    public ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(CancellationToken cancellationToken)
+    public ValueTask<TagHelperCollection> GetTagHelpersAsync(CancellationToken cancellationToken)
         => new(_state.TagHelpers);
 
     public bool ContainsDocument(string filePath)
@@ -143,7 +143,7 @@ public ImmutableArray<string> GetRelatedDocumentFilePaths(string documentFilePat
     string ILegacyProjectSnapshot.FilePath => FilePath;
     string? ILegacyProjectSnapshot.RootNamespace => RootNamespace;
     LanguageVersion ILegacyProjectSnapshot.CSharpLanguageVersion => CSharpLanguageVersion;
-    ImmutableArray<TagHelperDescriptor> ILegacyProjectSnapshot.TagHelpers => ProjectWorkspaceState.TagHelpers;
+    TagHelperCollection ILegacyProjectSnapshot.TagHelpers => ProjectWorkspaceState.TagHelpers;
 
     RazorProjectEngine ILegacyProjectSnapshot.GetProjectEngine()
         => _state.ProjectEngine;
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs
index 22313f45b1d..37c53816b57 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectState.cs
@@ -79,7 +79,7 @@ public static ProjectState Create(
         IProjectEngineFactoryProvider projectEngineFactoryProvider)
         => new(hostProject, projectEngineFactoryProvider);
 
-    public ImmutableArray<TagHelperDescriptor> TagHelpers => ProjectWorkspaceState.TagHelpers;
+    public TagHelperCollection TagHelpers => ProjectWorkspaceState.TagHelpers;
 
     public LanguageVersion CSharpLanguageVersion => HostProject.Configuration.CSharpLanguageVersion;
 
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectWorkspaceState.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectWorkspaceState.cs
index 6a550021f72..98eba74d385 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectWorkspaceState.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/ProjectWorkspaceState.cs
@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Immutable;
-using System.Linq;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.Extensions.Internal;
 
@@ -11,18 +9,18 @@ namespace Microsoft.CodeAnalysis.Razor.ProjectSystem;
 
 internal sealed class ProjectWorkspaceState : IEquatable<ProjectWorkspaceState>
 {
-    public static readonly ProjectWorkspaceState Default = new(ImmutableArray<TagHelperDescriptor>.Empty);
+    public static readonly ProjectWorkspaceState Default = new(TagHelperCollection.Empty);
 
-    public ImmutableArray<TagHelperDescriptor> TagHelpers { get; }
+    public TagHelperCollection TagHelpers { get; }
 
-    private ProjectWorkspaceState(
-        ImmutableArray<TagHelperDescriptor> tagHelpers)
+    public bool IsDefault => TagHelpers.IsEmpty;
+
+    private ProjectWorkspaceState(TagHelperCollection tagHelpers)
     {
         TagHelpers = tagHelpers;
     }
 
-    public static ProjectWorkspaceState Create(
-        ImmutableArray<TagHelperDescriptor> tagHelpers)
+    public static ProjectWorkspaceState Create(TagHelperCollection tagHelpers)
         => tagHelpers.IsEmpty
             ? Default
             : new(tagHelpers);
@@ -32,7 +30,7 @@ public override bool Equals(object? obj)
 
     public bool Equals(ProjectWorkspaceState? other)
         => other is not null &&
-           TagHelpers.SequenceEqual(other.TagHelpers);
+           TagHelpers.Equals(other.TagHelpers);
 
     public override int GetHashCode()
     {
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Rename/RenameService.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Rename/RenameService.cs
index 95d6b3d0db8..4e817a3494a 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Rename/RenameService.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Rename/RenameService.cs
@@ -17,7 +17,6 @@
 using Microsoft.CodeAnalysis.Razor.DocumentMapping;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Razor.Workspaces;
-using RazorSyntaxKind = Microsoft.AspNetCore.Razor.Language.SyntaxKind;
 using RazorSyntaxNode = Microsoft.AspNetCore.Razor.Language.Syntax.SyntaxNode;
 
 namespace Microsoft.CodeAnalysis.Razor.Rename;
@@ -46,14 +45,13 @@ public async Task<RenameResult> TryGetRazorRenameEditsAsync(
 
         var codeDocument = await documentContext.GetCodeDocumentAsync(cancellationToken).ConfigureAwait(false);
 
-        var originTagHelpers = await GetOriginTagHelpersAsync(documentContext, positionInfo.HostDocumentIndex, cancellationToken).ConfigureAwait(false);
-        if (originTagHelpers.IsDefaultOrEmpty)
+        if (!TryGetOriginTagHelpers(codeDocument, positionInfo.HostDocumentIndex, out var originTagHelpers))
         {
             return new(Edit: null);
         }
 
         var originComponentDocumentSnapshot = await _componentSearchEngine
-            .TryLocateComponentAsync(originTagHelpers.First(), solutionQueryOperations, cancellationToken)
+            .TryLocateComponentAsync(originTagHelpers.Primary, solutionQueryOperations, cancellationToken)
             .ConfigureAwait(false);
         if (originComponentDocumentSnapshot is null)
         {
@@ -69,17 +67,28 @@ public async Task<RenameResult> TryGetRazorRenameEditsAsync(
             return new(Edit: null, FallbackToCSharp: false);
         }
 
-        using var _ = ListPool<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>>.GetPooledObject(out var documentChanges);
+        using var documentChanges = new PooledArrayBuilder<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>>();
+
         var fileRename = GetRenameFileEdit(originComponentDocumentFilePath, newPath);
         documentChanges.Add(fileRename);
-        AddEditsForCodeDocument(documentChanges, originTagHelpers, newName, new(documentContext.Uri), codeDocument);
-        AddAdditionalFileRenames(documentChanges, originComponentDocumentFilePath, newPath);
+
+        AddEditsForCodeDocument(ref documentChanges.AsRef(), originTagHelpers, newName, new(documentContext.Uri), codeDocument);
+        AddAdditionalFileRenames(ref documentChanges.AsRef(), originComponentDocumentFilePath, newPath);
 
         var documentSnapshots = GetAllDocumentSnapshots(documentContext.FilePath, solutionQueryOperations);
 
         foreach (var documentSnapshot in documentSnapshots)
         {
-            await AddEditsForCodeDocumentAsync(documentChanges, originTagHelpers, newName, documentSnapshot, cancellationToken).ConfigureAwait(false);
+            if (!documentSnapshot.FileKind.IsComponent())
+            {
+                continue;
+            }
+
+            // VS Code in Windows expects path to start with '/'
+            var uri = new DocumentUri(LspFactory.CreateFilePathUri(documentSnapshot.FilePath, _languageServerFeatureOptions));
+            var generatedOutput = await documentSnapshot.GetGeneratedOutputAsync(cancellationToken).ConfigureAwait(false);
+
+            AddEditsForCodeDocument(ref documentChanges.AsRef(), originTagHelpers, newName, uri, generatedOutput);
         }
 
         foreach (var documentChange in documentChanges)
@@ -91,9 +100,9 @@ public async Task<RenameResult> TryGetRazorRenameEditsAsync(
             }
         }
 
-        return new(new WorkspaceEdit
+        return new(Edit: new()
         {
-            DocumentChanges = documentChanges.ToArray(),
+            DocumentChanges = documentChanges.ToArrayAndClear()
         });
     }
 
@@ -131,14 +140,19 @@ private static ImmutableArray<IDocumentSnapshot> GetAllDocumentSnapshots(string
         return documentSnapshots.ToImmutableAndClear();
     }
 
-    private void AddAdditionalFileRenames(List<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>> documentChanges, string oldFilePath, string newFilePath)
+    private void AddAdditionalFileRenames(
+        ref PooledArrayBuilder<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>> documentChanges,
+        string oldFilePath, string newFilePath)
     {
-        TryAdd(".cs");
-        TryAdd(".css");
+        TryAdd(".cs", ref documentChanges);
+        TryAdd(".css", ref documentChanges);
 
-        void TryAdd(string extension)
+        void TryAdd(
+            string extension,
+            ref PooledArrayBuilder<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>> documentChanges)
         {
             var changedPath = oldFilePath + extension;
+
             if (_fileSystem.FileExists(changedPath))
             {
                 documentChanges.Add(GetRenameFileEdit(changedPath, newFilePath + extension));
@@ -147,7 +161,7 @@ void TryAdd(string extension)
     }
 
     private RenameFile GetRenameFileEdit(string oldFilePath, string newFilePath)
-        => new RenameFile
+        => new()
         {
             OldDocumentUri = new(LspFactory.CreateFilePathUri(oldFilePath, _languageServerFeatureOptions)),
             NewDocumentUri = new(LspFactory.CreateFilePathUri(newFilePath, _languageServerFeatureOptions)),
@@ -160,115 +174,161 @@ private static string MakeNewPath(string originalPath, string newName)
         return Path.Combine(directoryName, newFileName);
     }
 
-    private async Task AddEditsForCodeDocumentAsync(
-        List<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>> documentChanges,
-        ImmutableArray<TagHelperDescriptor> originTagHelpers,
+    private static void AddEditsForCodeDocument(
+        ref PooledArrayBuilder<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>> documentChanges,
+        OriginTagHelpers originTagHelpers,
         string newName,
-        IDocumentSnapshot documentSnapshot,
-        CancellationToken cancellationToken)
+        DocumentUri uri,
+        RazorCodeDocument codeDocument)
     {
-        if (!documentSnapshot.FileKind.IsComponent())
+        var documentIdentifier = new OptionalVersionedTextDocumentIdentifier { DocumentUri = uri };
+
+        using var elements = new PooledArrayBuilder<MarkupTagHelperElementSyntax>();
+
+        foreach (var node in codeDocument.GetRequiredSyntaxRoot().DescendantNodes())
         {
-            return;
+            if (node is MarkupTagHelperElementSyntax element)
+            {
+                elements.Add(element);
+            }
         }
 
-        var codeDocument = await documentSnapshot.GetGeneratedOutputAsync(cancellationToken).ConfigureAwait(false);
+        // Collect all edits first, then de-duplicate them by range.
+        using var allEdits = new PooledArrayBuilder<SumType<TextEdit, AnnotatedTextEdit>>();
 
-        // VS Code in Windows expects path to start with '/'
-        var uri = new DocumentUri(LspFactory.CreateFilePathUri(documentSnapshot.FilePath, _languageServerFeatureOptions));
+        if (TryCollectEdits(originTagHelpers.Primary, newName, codeDocument.Source, in elements, ref allEdits.AsRef()) &&
+            TryCollectEdits(originTagHelpers.Associated, newName, codeDocument.Source, in elements, ref allEdits.AsRef()))
+        {
+            var uniqueEdits = GetUniqueEdits(ref allEdits.AsRef());
 
-        AddEditsForCodeDocument(documentChanges, originTagHelpers, newName, uri, codeDocument);
-    }
+            if (uniqueEdits.Length > 0)
+            {
+                documentChanges.Add(new TextDocumentEdit
+                {
+                    TextDocument = documentIdentifier,
+                    Edits = uniqueEdits,
+                });
+            }
+        }
 
-    private static void AddEditsForCodeDocument(
-        List<SumType<TextDocumentEdit, CreateFile, RenameFile, DeleteFile>> documentChanges,
-        ImmutableArray<TagHelperDescriptor> originTagHelpers,
-        string newName,
-        DocumentUri uri,
-        RazorCodeDocument codeDocument)
-    {
-        var documentIdentifier = new OptionalVersionedTextDocumentIdentifier { DocumentUri = uri };
-        var tagHelperElements = codeDocument.GetRequiredSyntaxRoot()
-            .DescendantNodes()
-            .OfType<MarkupTagHelperElementSyntax>();
+        return;
 
-        foreach (var originTagHelper in originTagHelpers)
+        static bool TryCollectEdits(
+            TagHelperDescriptor tagHelper,
+            string newName,
+            RazorSourceDocument sourceDocument,
+            ref readonly PooledArrayBuilder<MarkupTagHelperElementSyntax> elements,
+            ref PooledArrayBuilder<SumType<TextEdit, AnnotatedTextEdit>> edits)
         {
             var editedName = newName;
-            if (originTagHelper.IsFullyQualifiedNameMatch)
+
+            if (tagHelper.IsFullyQualifiedNameMatch)
             {
                 // Fully qualified binding, our "new name" needs to be fully qualified.
-                var @namespace = originTagHelper.TypeNamespace;
+                var @namespace = tagHelper.TypeNamespace;
                 if (@namespace == null)
                 {
-                    return;
+                    return false;
                 }
 
-                // The origin TagHelper was fully qualified so any fully qualified rename locations we find will need a fully qualified renamed edit.
+                // The origin TagHelper was fully qualified so any fully qualified rename locations
+                // we find will need a fully qualified renamed edit.
                 editedName = $"{@namespace}.{newName}";
             }
 
-            foreach (var node in tagHelperElements)
+            foreach (var element in elements)
             {
-                if (node is MarkupTagHelperElementSyntax { TagHelperInfo.BindingResult: var binding } tagHelperElement &&
-                    BindingContainsTagHelper(originTagHelper, binding))
+                if (element.TagHelperInfo.BindingResult.TagHelpers.Contains(tagHelper))
                 {
-                    documentChanges.Add(new TextDocumentEdit
+                    var startTagEdit = LspFactory.CreateTextEdit(element.StartTag.Name.GetRange(sourceDocument), editedName);
+
+                    edits.Add(startTagEdit);
+
+                    if (element.EndTag is MarkupTagHelperEndTagSyntax endTag)
                     {
-                        TextDocument = documentIdentifier,
-                        Edits = CreateEditsForMarkupTagHelperElement(tagHelperElement, codeDocument, editedName),
-                    });
+                        var endTagEdit = LspFactory.CreateTextEdit(endTag.Name.GetRange(sourceDocument), editedName);
+
+                        edits.Add(endTagEdit);
+                    }
                 }
             }
-        }
-    }
 
-    private static SumType<TextEdit, AnnotatedTextEdit>[] CreateEditsForMarkupTagHelperElement(MarkupTagHelperElementSyntax element, RazorCodeDocument codeDocument, string newName)
-    {
-        var startTagEdit = LspFactory.CreateTextEdit(element.StartTag.Name.GetRange(codeDocument.Source), newName);
+            return true;
+        }
 
-        if (element.EndTag is MarkupTagHelperEndTagSyntax endTag)
+        static SumType<TextEdit, AnnotatedTextEdit>[] GetUniqueEdits(
+            ref PooledArrayBuilder<SumType<TextEdit, AnnotatedTextEdit>> edits)
         {
-            var endTagEdit = LspFactory.CreateTextEdit(endTag.Name.GetRange(codeDocument.Source), newName);
+            if (edits.Count == 0)
+            {
+                return [];
+            }
 
-            return [startTagEdit, endTagEdit];
-        }
+            // De-duplicate edits by range.
+            using var uniqueEdits = new PooledArrayBuilder<SumType<TextEdit, AnnotatedTextEdit>>(edits.Count);
+            using var _ = HashSetPool<LspRange>.GetPooledObject(out var seenRanges);
+
+#if NET
+            seenRanges.EnsureCapacity(edits.Count);
+#endif
+
+            foreach (var edit in edits)
+            {
+                if (edit.TryGetFirst(out var textEdit))
+                {
+                    if (seenRanges.Add(textEdit.Range))
+                    {
+                        uniqueEdits.Add(edit);
+                    }
+                }
+                else if (edit.TryGetSecond(out var annotatedEdit))
+                {
+                    if (seenRanges.Add(annotatedEdit.Range))
+                    {
+                        uniqueEdits.Add(edit);
+                    }
+                }
+            }
 
-        return [startTagEdit];
+            return uniqueEdits.ToArrayAndClear();
+        }
     }
 
-    private static bool BindingContainsTagHelper(TagHelperDescriptor tagHelper, TagHelperBinding potentialBinding)
-        => potentialBinding.Descriptors.Any(descriptor => descriptor.Equals(tagHelper));
+    private readonly record struct OriginTagHelpers(TagHelperDescriptor Primary, TagHelperDescriptor Associated);
 
-    private static async Task<ImmutableArray<TagHelperDescriptor>> GetOriginTagHelpersAsync(DocumentContext documentContext, int absoluteIndex, CancellationToken cancellationToken)
+    private static bool TryGetOriginTagHelpers(RazorCodeDocument codeDocument, int absoluteIndex, out OriginTagHelpers originTagHelpers)
     {
-        var owner = await documentContext.GetSyntaxNodeAsync(absoluteIndex, cancellationToken).ConfigureAwait(false);
+        var owner = codeDocument.GetRequiredSyntaxRoot().FindInnermostNode(absoluteIndex);
         if (owner is null)
         {
             Debug.Fail("Owner should never be null.");
-            return default;
+            originTagHelpers = default;
+            return false;
         }
 
         if (!TryGetTagHelperBinding(owner, absoluteIndex, out var binding))
         {
-            return default;
+            originTagHelpers = default;
+            return false;
         }
 
         // Can only have 1 component TagHelper belonging to an element at a time
-        var primaryTagHelper = binding.Descriptors.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
+        var primaryTagHelper = binding.TagHelpers.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
         if (primaryTagHelper is null)
         {
-            return default;
+            originTagHelpers = default;
+            return false;
         }
 
-        var tagHelpers = await documentContext.Snapshot.Project.GetTagHelpersAsync(cancellationToken).ConfigureAwait(false);
-        var associatedTagHelper = FindAssociatedTagHelper(primaryTagHelper, tagHelpers);
-        if (associatedTagHelper is null)
+        var tagHelpers = codeDocument.GetRequiredTagHelpers();
+        if (!TryFindAssociatedTagHelper(primaryTagHelper, tagHelpers, out var associatedTagHelper))
         {
-            return default;
+            originTagHelpers = default;
+            return false;
         }
 
-        return [primaryTagHelper, associatedTagHelper];
+        originTagHelpers = new(primaryTagHelper, associatedTagHelper);
+        return true;
     }
 
     private static bool TryGetTagHelperBinding(RazorSyntaxNode owner, int absoluteIndex, [NotNullWhen(true)] out TagHelperBinding? binding)
@@ -282,8 +342,7 @@ private static bool TryGetTagHelperBinding(RazorSyntaxNode owner, int absoluteIn
 
         // A rename of a start tag could have an "owner" of one of its attributes, so we do a bit more checking
         // to support this case
-        var node = owner.FirstAncestorOrSelf<RazorSyntaxNode>(n => n.Kind == RazorSyntaxKind.MarkupTagHelperStartTag);
-        if (node is not MarkupTagHelperStartTagSyntax tagHelperStartTag)
+        if (owner.FirstAncestorOrSelf<MarkupTagHelperStartTagSyntax>() is not { } tagHelperStartTag)
         {
             binding = null;
             return false;
@@ -308,33 +367,29 @@ private static bool TryGetTagHelperBinding(RazorSyntaxNode owner, int absoluteIn
         return false;
     }
 
-    private static TagHelperDescriptor? FindAssociatedTagHelper(TagHelperDescriptor tagHelper, ImmutableArray<TagHelperDescriptor> tagHelpers)
+    private static bool TryFindAssociatedTagHelper(
+        TagHelperDescriptor primary,
+        TagHelperCollection tagHelpers,
+        [NotNullWhen(true)] out TagHelperDescriptor? associated)
     {
-        var typeName = tagHelper.TypeName;
-        var assemblyName = tagHelper.AssemblyName;
-        foreach (var currentTagHelper in tagHelpers)
-        {
-            if (tagHelper == currentTagHelper)
-            {
-                // Same as the primary, we're looking for our other pair.
-                continue;
-            }
+        var typeName = primary.TypeName;
+        var assemblyName = primary.AssemblyName;
 
-            if (typeName != currentTagHelper.TypeName)
-            {
-                continue;
-            }
-
-            if (assemblyName != currentTagHelper.AssemblyName)
+        foreach (var tagHelper in tagHelpers)
+        {
+            if (typeName == tagHelper.TypeName &&
+                assemblyName == tagHelper.AssemblyName &&
+                !tagHelper.Equals(primary))
             {
-                continue;
+                // Found our associated TagHelper, there should only ever be
+                // one other associated TagHelper (fully qualified and non-fully qualified).
+                associated = tagHelper;
+                return true;
             }
-
-            // Found our associated TagHelper, there should only ever be 1 other associated TagHelper (fully qualified and non-fully qualified).
-            return currentTagHelper;
         }
 
         Debug.Fail("Components should always have an associated TagHelper.");
-        return null;
+        associated = null;
+        return false;
     }
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/SemanticTokens/SemanticTokensVisitor.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/SemanticTokens/SemanticTokensVisitor.cs
index ab8f682eb3b..2d5ff0eeed3 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/SemanticTokens/SemanticTokensVisitor.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/SemanticTokens/SemanticTokensVisitor.cs
@@ -490,7 +490,7 @@ private static bool IsComponent(SyntaxNode node)
     {
         if (node is MarkupTagHelperElementSyntax { TagHelperInfo.BindingResult: var binding })
         {
-            var componentDescriptor = binding.Descriptors.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
+            var componentDescriptor = binding.TagHelpers.FirstOrDefault(static d => d.Kind == TagHelperKind.Component);
             return componentDescriptor is not null;
         }
         else if (node is MarkupTagHelperStartTagSyntax startTag)
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/FetchTagHelpersResult.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/FetchTagHelpersResult.cs
index 9a9c95ada4a..64f2ab367c8 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/FetchTagHelpersResult.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/FetchTagHelpersResult.cs
@@ -1,12 +1,11 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 
 namespace Microsoft.CodeAnalysis.Razor.Serialization;
 
-internal sealed record FetchTagHelpersResult(ImmutableArray<TagHelperDescriptor> TagHelpers)
+internal sealed record FetchTagHelpersResult(TagHelperCollection TagHelpers)
 {
-    public static readonly FetchTagHelpersResult Empty = new(ImmutableArray<TagHelperDescriptor>.Empty);
+    public static readonly FetchTagHelpersResult Empty = new(TagHelperCollection.Empty);
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/FetchTagHelpersResultFormatter.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/FetchTagHelpersResultFormatter.cs
index 351bb25397d..96b4f4008f1 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/FetchTagHelpersResultFormatter.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/FetchTagHelpersResultFormatter.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using MessagePack;
 using Microsoft.AspNetCore.Razor.Language;
 
@@ -17,7 +16,7 @@ private FetchTagHelpersResultFormatter()
 
     public override FetchTagHelpersResult Deserialize(ref MessagePackReader reader, SerializerCachingOptions options)
     {
-        var tagHelpers = reader.Deserialize<ImmutableArray<TagHelperDescriptor>>(options);
+        var tagHelpers = reader.Deserialize<TagHelperCollection>(options);
 
         return new(tagHelpers);
     }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/ProjectWorkspaceStateFormatter.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/ProjectWorkspaceStateFormatter.cs
index 9da11b26804..b9fb89b3eea 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/ProjectWorkspaceStateFormatter.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Formatters/ProjectWorkspaceStateFormatter.cs
@@ -1,14 +1,10 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using MessagePack;
+using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.Language;
-using Microsoft.AspNetCore.Razor.PooledObjects;
-using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
-using Microsoft.CodeAnalysis.Razor.Serialization.MessagePack.Formatters.TagHelpers;
-using Microsoft.CodeAnalysis.Razor.Utilities;
 
 namespace Microsoft.CodeAnalysis.Razor.Serialization.MessagePack.Formatters;
 
@@ -22,42 +18,13 @@ private ProjectWorkspaceStateFormatter()
 
     public override ProjectWorkspaceState Deserialize(ref MessagePackReader reader, SerializerCachingOptions options)
     {
-        reader.ReadArrayHeaderAndVerify(2);
-
-        var checksums = reader.Deserialize<ImmutableArray<Checksum>>(options);
-
-        reader.ReadArrayHeaderAndVerify(checksums.Length);
-
-        using var builder = new PooledArrayBuilder<TagHelperDescriptor>(capacity: checksums.Length);
-        var cache = TagHelperCache.Default;
-
-        foreach (var checksum in checksums)
-        {
-            if (!cache.TryGet(checksum, out var tagHelper))
-            {
-                tagHelper = TagHelperFormatter.Instance.Deserialize(ref reader, options);
-                cache.TryAdd(checksum, tagHelper);
-            }
-            else
-            {
-                TagHelperFormatter.Instance.Skim(ref reader, options);
-            }
-
-            builder.Add(tagHelper);
-        }
-
-        var tagHelpers = builder.ToImmutableAndClear();
+        var tagHelpers = reader.Deserialize<TagHelperCollection>(options).AssumeNotNull();
 
         return ProjectWorkspaceState.Create(tagHelpers);
     }
 
     public override void Serialize(ref MessagePackWriter writer, ProjectWorkspaceState value, SerializerCachingOptions options)
     {
-        writer.WriteArrayHeader(2);
-
-        var checksums = value.TagHelpers.SelectAsArray(x => x.Checksum);
-
-        writer.Serialize(checksums, options);
         writer.Serialize(value.TagHelpers, options);
     }
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Resolvers/FetchTagHelpersResultResolver.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Resolvers/FetchTagHelpersResultResolver.cs
index 0761038f1ee..c9c1491915f 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Resolvers/FetchTagHelpersResultResolver.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/Resolvers/FetchTagHelpersResultResolver.cs
@@ -48,6 +48,7 @@ private static class TypeToFormatterMap
             RazorDiagnosticFormatter.Instance,
             RequiredAttributeFormatter.Instance,
             TagHelperFormatter.Instance,
+            TagHelperCollectionFormatter.Instance,
             TagMatchingRuleFormatter.Instance,
             TypeNameObjectFormatter.Instance
         };
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/SerializationFormat.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/SerializationFormat.cs
index e2ff382a39d..e5b0ca9684c 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/SerializationFormat.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Serialization/MessagePack/SerializationFormat.cs
@@ -9,5 +9,5 @@ internal static class SerializationFormat
     // or any of the types that compose it changes. This includes: RazorConfiguration,
     // ProjectWorkspaceState, TagHelperDescriptor, and DocumentSnapshotHandle.
     // NOTE: If this version is changed, a coordinated insertion is required between Roslyn and Razor for the C# extension.
-    public const int Version = 15;
+    public const int Version = 16;
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/TagHelperFacts.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/TagHelperFacts.cs
index 199c856d359..1c3b53a4363 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/TagHelperFacts.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/TagHelperFacts.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.PooledObjects;
@@ -19,10 +20,7 @@ internal static class TagHelperFacts
         string? parentTag,
         bool parentIsTagHelper)
     {
-        if (documentContext is null)
-        {
-            throw new ArgumentNullException(nameof(documentContext));
-        }
+        ArgHelper.ThrowIfNull(documentContext);
 
         if (attributes.IsDefault)
         {
@@ -34,7 +32,7 @@ internal static class TagHelperFacts
             return null;
         }
 
-        if (documentContext.TagHelpers.Length == 0)
+        if (documentContext.TagHelpers.Count == 0)
         {
             return null;
         }
@@ -49,24 +47,13 @@ public static ImmutableArray<BoundAttributeDescriptor> GetBoundTagHelperAttribut
         string attributeName,
         TagHelperBinding binding)
     {
-        if (documentContext is null)
-        {
-            throw new ArgumentNullException(nameof(documentContext));
-        }
-
-        if (attributeName is null)
-        {
-            throw new ArgumentNullException(nameof(attributeName));
-        }
-
-        if (binding is null)
-        {
-            throw new ArgumentNullException(nameof(binding));
-        }
+        ArgHelper.ThrowIfNull(documentContext);
+        ArgHelper.ThrowIfNull(attributeName);
+        ArgHelper.ThrowIfNull(binding);
 
         using var matchingBoundAttributes = new PooledArrayBuilder<BoundAttributeDescriptor>();
 
-        foreach (var tagHelper in binding.Descriptors)
+        foreach (var tagHelper in binding.TagHelpers)
         {
             foreach (var boundAttribute in tagHelper.BoundAttributes)
             {
@@ -83,85 +70,73 @@ public static ImmutableArray<BoundAttributeDescriptor> GetBoundTagHelperAttribut
         return matchingBoundAttributes.ToImmutableAndClear();
     }
 
-    public static ImmutableArray<TagHelperDescriptor> GetTagHelpersGivenTag(
+    public static TagHelperCollection GetTagHelpersGivenTag(
         TagHelperDocumentContext documentContext,
         string tagName,
         string? parentTag)
     {
-        if (documentContext is null)
-        {
-            throw new ArgumentNullException(nameof(documentContext));
-        }
+        ArgHelper.ThrowIfNull(documentContext);
+        ArgHelper.ThrowIfNull(tagName);
 
-        if (tagName is null)
+        if (documentContext.TagHelpers.IsEmpty)
         {
-            throw new ArgumentNullException(nameof(tagName));
+            return [];
         }
 
-        if (documentContext?.TagHelpers is not { Length: > 0 } tagHelpers)
-        {
-            return ImmutableArray<TagHelperDescriptor>.Empty;
-        }
+        var tagNameWithoutPrefix = tagName.AsMemory();
 
-        var prefix = documentContext?.Prefix ?? string.Empty;
-        if (!tagName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
+        if (documentContext.Prefix is { Length: > 0 } prefix)
         {
-            // Can't possibly match TagHelpers, it doesn't start with the TagHelperPrefix.
-            return ImmutableArray<TagHelperDescriptor>.Empty;
-        }
-
-        using var matchingDescriptors = new PooledArrayBuilder<TagHelperDescriptor>();
+            if (!tagNameWithoutPrefix.Span.StartsWith(prefix.AsSpan(), StringComparison.OrdinalIgnoreCase))
+            {
+                // 'tagName' can't possibly match TagHelpers if it doesn't start with the provided prefix.
+                return [];
+            }
 
-        var tagNameWithoutPrefix = tagName.AsSpan()[prefix.Length..];
+            tagNameWithoutPrefix = tagNameWithoutPrefix[prefix.Length..];
+        }
 
-        foreach (var tagHelper in tagHelpers)
+        return documentContext.TagHelpers.Where(state: (tagNameWithoutPrefix, parentTag), static (tagHelper, state) =>
         {
             foreach (var rule in tagHelper.TagMatchingRules)
             {
-                if (TagHelperMatchingConventions.SatisfiesTagName(rule, tagNameWithoutPrefix) &&
-                    TagHelperMatchingConventions.SatisfiesParentTag(rule, parentTag.AsSpanOrDefault()))
+                if (TagHelperMatchingConventions.SatisfiesTagName(rule, state.tagNameWithoutPrefix.Span) &&
+                    TagHelperMatchingConventions.SatisfiesParentTag(rule, state.parentTag.AsSpan()))
                 {
-                    matchingDescriptors.Add(tagHelper);
-                    break;
+                    return true;
                 }
             }
-        }
 
-        return matchingDescriptors.ToImmutableAndClear();
+            return false;
+        });
     }
 
-    public static ImmutableArray<TagHelperDescriptor> GetTagHelpersGivenParent(TagHelperDocumentContext documentContext, string? parentTag)
+    public static TagHelperCollection GetTagHelpersGivenParent(TagHelperDocumentContext documentContext, string? parentTag)
     {
-        if (documentContext is null)
-        {
-            throw new ArgumentNullException(nameof(documentContext));
-        }
+        ArgHelper.ThrowIfNull(documentContext);
 
-        if (documentContext?.TagHelpers is not { Length: > 0 } tagHelpers)
+        if (documentContext.TagHelpers.IsEmpty)
         {
-            return ImmutableArray<TagHelperDescriptor>.Empty;
+            return [];
         }
 
-        using var matchingDescriptors = new PooledArrayBuilder<TagHelperDescriptor>();
-
-        foreach (var descriptor in tagHelpers)
+        return documentContext.TagHelpers.Where(parentTag, static (tagHelper, parentTag) =>
         {
-            foreach (var rule in descriptor.TagMatchingRules)
+            foreach (var rule in tagHelper.TagMatchingRules)
             {
-                if (TagHelperMatchingConventions.SatisfiesParentTag(rule, parentTag.AsSpanOrDefault()))
+                if (TagHelperMatchingConventions.SatisfiesParentTag(rule, parentTag.AsSpan()))
                 {
-                    matchingDescriptors.Add(descriptor);
-                    break;
+                    return true;
                 }
             }
-        }
 
-        return matchingDescriptors.ToImmutableAndClear();
+            return false;
+        });
     }
 
     public static ImmutableArray<KeyValuePair<string, string>> StringifyAttributes(SyntaxList<RazorSyntaxNode> attributes)
     {
-        using var stringifiedAttributes = new PooledArrayBuilder<KeyValuePair<string, string>>();
+        using var builder = new PooledArrayBuilder<KeyValuePair<string, string>>();
 
         foreach (var attribute in attributes)
         {
@@ -171,14 +146,14 @@ public static ImmutableArray<KeyValuePair<string, string>> StringifyAttributes(S
                     {
                         var name = tagHelperAttribute.Name.GetContent();
                         var value = tagHelperAttribute.Value?.GetContent() ?? string.Empty;
-                        stringifiedAttributes.Add(new KeyValuePair<string, string>(name, value));
+                        builder.Add(KeyValuePair.Create(name, value));
                         break;
                     }
 
                 case MarkupMinimizedTagHelperAttributeSyntax minimizedTagHelperAttribute:
                     {
                         var name = minimizedTagHelperAttribute.Name.GetContent();
-                        stringifiedAttributes.Add(new KeyValuePair<string, string>(name, string.Empty));
+                        builder.Add(KeyValuePair.Create(name, string.Empty));
                         break;
                     }
 
@@ -186,14 +161,14 @@ public static ImmutableArray<KeyValuePair<string, string>> StringifyAttributes(S
                     {
                         var name = markupAttribute.Name.GetContent();
                         var value = markupAttribute.Value?.GetContent() ?? string.Empty;
-                        stringifiedAttributes.Add(new KeyValuePair<string, string>(name, value));
+                        builder.Add(KeyValuePair.Create(name, value));
                         break;
                     }
 
                 case MarkupMinimizedAttributeBlockSyntax minimizedMarkupAttribute:
                     {
                         var name = minimizedMarkupAttribute.Name.GetContent();
-                        stringifiedAttributes.Add(new KeyValuePair<string, string>(name, string.Empty));
+                        builder.Add(KeyValuePair.Create(name, string.Empty));
                         break;
                     }
 
@@ -201,20 +176,20 @@ public static ImmutableArray<KeyValuePair<string, string>> StringifyAttributes(S
                     {
                         var name = directiveAttribute.FullName;
                         var value = directiveAttribute.Value?.GetContent() ?? string.Empty;
-                        stringifiedAttributes.Add(new KeyValuePair<string, string>(name, value));
+                        builder.Add(KeyValuePair.Create(name, value));
                         break;
                     }
 
                 case MarkupMinimizedTagHelperDirectiveAttributeSyntax minimizedDirectiveAttribute:
                     {
                         var name = minimizedDirectiveAttribute.FullName;
-                        stringifiedAttributes.Add(new KeyValuePair<string, string>(name, string.Empty));
+                        builder.Add(KeyValuePair.Create(name, string.Empty));
                         break;
                     }
             }
         }
 
-        return stringifiedAttributes.ToImmutableAndClear();
+        return builder.ToImmutableAndClear();
     }
 
     public static (string? ancestorTagName, bool ancestorIsTagHelper) GetNearestAncestorTagInfo(IEnumerable<SyntaxNode> ancestors)
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Tooltip/BoundAttributeDescriptionInfo.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Tooltip/BoundAttributeDescriptionInfo.cs
index fc14ca25ebb..1a2c3d57396 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Tooltip/BoundAttributeDescriptionInfo.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Tooltip/BoundAttributeDescriptionInfo.cs
@@ -9,25 +9,18 @@ namespace Microsoft.CodeAnalysis.Razor.Tooltip;
 
 internal record BoundAttributeDescriptionInfo(string ReturnTypeName, string TypeName, string PropertyName, string? Documentation = null)
 {
-    public static BoundAttributeDescriptionInfo From(BoundAttributeParameterDescriptor parameterAttribute, string parentTagHelperTypeName)
+    public static BoundAttributeDescriptionInfo From(BoundAttributeParameterDescriptor parameter)
     {
-        if (parameterAttribute is null)
-        {
-            throw new ArgumentNullException(nameof(parameterAttribute));
-        }
-
-        if (parentTagHelperTypeName is null)
-        {
-            throw new ArgumentNullException(nameof(parentTagHelperTypeName));
-        }
+        ArgHelper.ThrowIfNull(parameter);
 
-        var propertyName = parameterAttribute.PropertyName;
+        var parentTagHelperTypeName = parameter.Parent.Parent.TypeName;
+        var propertyName = parameter.PropertyName;
 
         return new BoundAttributeDescriptionInfo(
-            parameterAttribute.TypeName,
+            parameter.TypeName,
             parentTagHelperTypeName,
             propertyName,
-            parameterAttribute.Documentation);
+            parameter.Documentation);
     }
 
     public static BoundAttributeDescriptionInfo From(BoundAttributeDescriptor boundAttribute, bool isIndexer)
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/DevTools/RemoteDevToolsService.cs b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/DevTools/RemoteDevToolsService.cs
index b4353f1f95a..602c6185ea9 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/DevTools/RemoteDevToolsService.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/DevTools/RemoteDevToolsService.cs
@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -88,12 +86,12 @@ private static async ValueTask<FetchTagHelpersResult> GetTagHelpersJsonAsync(Rem
         {
             TagHelpersKind.All => codeDocument.GetTagHelpers(),
             TagHelpersKind.InScope => codeDocument.GetRequiredTagHelperContext().TagHelpers,
-            TagHelpersKind.Referenced => (IEnumerable<TagHelperDescriptor>?)codeDocument.GetReferencedTagHelpers(),
+            TagHelpersKind.Referenced => codeDocument.GetReferencedTagHelpers(),
             _ => []
         };
 
         tagHelpers ??= [];
-        return new FetchTagHelpersResult(tagHelpers.ToImmutableArray());
+        return new FetchTagHelpersResult(tagHelpers);
     }
 
     public ValueTask<SyntaxVisualizerTree?> GetRazorSyntaxTreeAsync(
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/GeneratorRunResult.cs b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/GeneratorRunResult.cs
index 0ba9b367fe2..299ec3e86a6 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/GeneratorRunResult.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/GeneratorRunResult.cs
@@ -20,7 +20,7 @@ internal readonly record struct GeneratorRunResult(RazorGeneratorResult Generato
 {
     public bool IsDefault => GeneratorResult is null && Project is null;
 
-    public IReadOnlyList<TagHelperDescriptor> TagHelpers => GeneratorResult.TagHelpers;
+    public TagHelperCollection TagHelpers => GeneratorResult.TagHelpers;
 
     public RazorCodeDocument? GetCodeDocument(string filePath)
         => GeneratorResult.GetCodeDocument(filePath);
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/RemoteProjectSnapshot.cs b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/RemoteProjectSnapshot.cs
index ad1a7558fba..c603e416dfc 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/RemoteProjectSnapshot.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/ProjectSystem/RemoteProjectSnapshot.cs
@@ -56,13 +56,13 @@ public IEnumerable<string> DocumentFilePaths
 
     public LanguageVersion CSharpLanguageVersion => ((CSharpParseOptions)_project.ParseOptions.AssumeNotNull()).LanguageVersion;
 
-    public async ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(CancellationToken cancellationToken)
+    public async ValueTask<TagHelperCollection> GetTagHelpersAsync(CancellationToken cancellationToken)
     {
         var generatorResult = await GeneratorRunResult.CreateAsync(throwIfNotFound: false, _project, SolutionSnapshot.SnapshotManager, cancellationToken).ConfigureAwait(false);
-        if (generatorResult.IsDefault)
-            return [];
 
-        return [.. generatorResult.TagHelpers];
+        return !generatorResult.IsDefault
+            ? generatorResult.TagHelpers
+            : [];
     }
 
     public RemoteDocumentSnapshot GetDocument(TextDocument document)
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperProviderService.cs b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperProviderService.cs
index dd49aa5d08b..1f46757b624 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperProviderService.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperProviderService.cs
@@ -2,10 +2,10 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Immutable;
+using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
-using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.ExternalAccess.Razor;
 using Microsoft.CodeAnalysis.Razor.Remote;
@@ -76,23 +76,23 @@ private async ValueTask<FetchTagHelpersResult> FetchTagHelpersCoreAsync(
 
         return new FetchTagHelpersResult(tagHelpers);
 
-        static bool TryGetCachedTagHelpers(ImmutableArray<Checksum> checksums, out ImmutableArray<TagHelperDescriptor> tagHelpers)
+        static bool TryGetCachedTagHelpers(ImmutableArray<Checksum> checksums, out TagHelperCollection tagHelpers)
         {
-            using var builder = new PooledArrayBuilder<TagHelperDescriptor>(capacity: checksums.Length);
+            using var builder = new TagHelperCollection.RefBuilder(initialCapacity: checksums.Length);
             var cache = TagHelperCache.Default;
 
             foreach (var checksum in checksums)
             {
                 if (!cache.TryGet(checksum, out var tagHelper))
                 {
-                    tagHelpers = ImmutableArray<TagHelperDescriptor>.Empty;
+                    tagHelpers = [];
                     return false;
                 }
 
                 builder.Add(tagHelper);
             }
 
-            tagHelpers = builder.ToImmutableAndClear();
+            tagHelpers = builder.ToCollection();
             return true;
         }
     }
@@ -117,7 +117,7 @@ private async ValueTask<TagHelperDeltaResult> GetTagHelpersDeltaCoreAsync(
 
         if (solution.GetProject(projectHandle.ProjectId) is not Project workspaceProject)
         {
-            checksums = ImmutableArray<Checksum>.Empty;
+            checksums = [];
         }
         else
         {
@@ -130,21 +130,22 @@ private async ValueTask<TagHelperDeltaResult> GetTagHelpersDeltaCoreAsync(
 
         return _tagHelperDeltaProvider.GetTagHelpersDelta(projectHandle.ProjectId, lastResultId, checksums);
 
-        static ImmutableArray<Checksum> GetChecksums(ImmutableArray<TagHelperDescriptor> tagHelpers)
+        static ImmutableArray<Checksum> GetChecksums(TagHelperCollection tagHelpers)
         {
-            using var builder = new PooledArrayBuilder<Checksum>(capacity: tagHelpers.Length);
+            var array = new Checksum[tagHelpers.Count];
 
             // Add each tag helpers to the cache so that we can retrieve them later if needed.
             var cache = TagHelperCache.Default;
+            var index = 0;
 
             foreach (var tagHelper in tagHelpers)
             {
                 var checksum = tagHelper.Checksum;
-                builder.Add(checksum);
+                array[index++] = checksum;
                 cache.TryAdd(checksum, tagHelper);
             }
 
-            return builder.ToImmutableAndClear();
+            return ImmutableCollectionsMarshal.AsImmutableArray(array);
         }
     }
 }
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperResolver.cs b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperResolver.cs
index 3e4707bc552..e3fdcd34971 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperResolver.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/TagHelpers/RemoteTagHelperResolver.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Composition;
 using System.Threading;
 using System.Threading.Tasks;
@@ -36,7 +35,7 @@ private static Dictionary<string, IProjectEngineFactory> CreateConfigurationName
         return map;
     }
 
-    public ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
+    public ValueTask<TagHelperCollection> GetTagHelpersAsync(
         Project workspaceProject,
         RazorConfiguration? configuration,
         CancellationToken cancellationToken)
@@ -44,7 +43,7 @@ public ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
             ? workspaceProject.GetTagHelpersAsync(CreateProjectEngine(configuration), _telemetryReporter, cancellationToken)
             : new([]);
 
-    private RazorProjectEngine CreateProjectEngine(RazorConfiguration configuration)
+    private static RazorProjectEngine CreateProjectEngine(RazorConfiguration configuration)
     {
         // If there's no factory to handle the configuration then fall back to a very basic configuration.
         //
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/OutOfProcTagHelperResolver.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/OutOfProcTagHelperResolver.cs
index bebcdbc5f97..2e890e6fdda 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/OutOfProcTagHelperResolver.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/OutOfProcTagHelperResolver.cs
@@ -40,7 +40,7 @@ internal class OutOfProcTagHelperResolver(
     private readonly ITelemetryReporter _telemetryReporter = telemetryReporter;
     private readonly TagHelperResultCache _resultCache = new();
 
-    public async ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
+    public async ValueTask<TagHelperCollection?> GetTagHelpersAsync(
         Project project,
         ProjectSnapshot projectSnapshot,
         CancellationToken cancellationToken)
@@ -52,7 +52,7 @@ public async ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
             var result = await ResolveTagHelpersOutOfProcessAsync(project, projectSnapshot, cancellationToken).ConfigureAwait(false);
 
             // We received tag helpers, so we're done.
-            if (!result.IsDefault)
+            if (result is not null)
             {
                 return result;
             }
@@ -70,11 +70,11 @@ public async ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
         catch (Exception ex) when (ex is not OperationCanceledException)
         {
             _logger.LogError(ex, $"Error encountered from project '{projectSnapshot.FilePath}':{Environment.NewLine}{ex}");
-            return default;
+            return null;
         }
     }
 
-    protected virtual async ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTagHelpersOutOfProcessAsync(Project project, ProjectSnapshot projectSnapshot, CancellationToken cancellationToken)
+    protected virtual async ValueTask<TagHelperCollection?> ResolveTagHelpersOutOfProcessAsync(Project project, ProjectSnapshot projectSnapshot, CancellationToken cancellationToken)
     {
         if (!_resultCache.TryGetId(project.Id, out var lastResultId))
         {
@@ -92,7 +92,7 @@ protected virtual async ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTa
         if (deltaResult is null)
         {
             // For some reason, TryInvokeAsync can return null if it is cancelled while fetching the client.
-            return default;
+            return null;
         }
 
         // Apply the delta we received to any cached checksums for the current project.
@@ -137,7 +137,7 @@ protected virtual async ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTa
             if (fetchResult is null)
             {
                 // For some reason, TryInvokeAsync can return null if it is cancelled while fetching the client.
-                return default;
+                return null;
             }
 
             var fetchedTagHelpers = fetchResult.TagHelpers;
@@ -149,7 +149,7 @@ protected virtual async ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTa
             }
 
             Debug.Assert(
-                checksumsToFetch.Length == fetchedTagHelpers.Length,
+                checksumsToFetch.Length == fetchedTagHelpers.Count,
                 $"{nameof(FetchTagHelpersResult)} should return the same number of tag helpers as checksums requested.");
 
             Debug.Assert(
@@ -159,7 +159,7 @@ protected virtual async ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTa
             // Be sure to add the tag helpers we just fetched to the cache.
             var cache = TagHelperCache.Default;
 
-            for (var i = 0; i < fetchedTagHelpers.Length; i++)
+            for (var i = 0; i < fetchedTagHelpers.Count; i++)
             {
                 var index = checksumIndicesBuilder[i];
                 Debug.Assert(result[index] is null);
@@ -169,14 +169,14 @@ protected virtual async ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTa
                 cache.TryAdd(fetchedTagHelper.Checksum, fetchedTagHelper);
             }
 
-            if (checksumsToFetch.Length != fetchedTagHelpers.Length)
+            if (checksumsToFetch.Length != fetchedTagHelpers.Count)
             {
                 _logger.LogWarning($"Expected to receive {checksumsToFetch.Length} tag helpers from Roslyn OOP, " +
-                    $"but received {fetchedTagHelpers.Length} instead. Returning a partial set of tag helpers.");
+                    $"but received {fetchedTagHelpers.Count} instead. Returning a partial set of tag helpers.");
 
                 // We didn't receive all the tag helpers we requested. This is bad. However, instead of failing,
                 // we'll just return the tag helpers we were able to retrieve.
-                using var resultBuilder = new PooledArrayBuilder<TagHelperDescriptor>(capacity: result.Length);
+                using var resultBuilder = new TagHelperCollection.RefBuilder(initialCapacity: result.Length);
 
                 foreach (var tagHelper in result)
                 {
@@ -186,11 +186,17 @@ protected virtual async ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTa
                     }
                 }
 
-                return resultBuilder.ToImmutableAndClear();
+                return resultBuilder.ToCollection();
             }
         }
 
-        return ImmutableCollectionsMarshal.AsImmutableArray(result);
+        // If we pass 'result' to TagHelperCollection.Create(...) the overload that takes
+        // a ReadOnlySpan<TagHelperDescriptor> will be called, resulting in 'result' being
+        // copied to a new array. By first wrapping 'result' in an ImmutableArray we ensure
+        // that TagHelperCollection.Create(...) slices 'result' into segments.
+        var resultArray = ImmutableCollectionsMarshal.AsImmutableArray(result);
+
+        return TagHelperCollection.Create(resultArray);
     }
 
     // Protected virtual for testing
@@ -224,7 +230,7 @@ protected ImmutableArray<Checksum> ProduceChecksumsFromDelta(ProjectId projectId
         return checksums;
     }
 
-    protected virtual ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTagHelpersInProcessAsync(
+    protected virtual ValueTask<TagHelperCollection> ResolveTagHelpersInProcessAsync(
         Project project,
         ProjectSnapshot projectSnapshot,
         CancellationToken cancellationToken)
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/ProjectStateUpdater.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/ProjectStateUpdater.cs
index 2d9bbca820f..80ad12ed5a1 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/ProjectStateUpdater.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/ProjectStateUpdater.cs
@@ -159,7 +159,7 @@ private async Task UpdateWorkspaceStateAsync(ProjectKey key, ProjectId? id, Canc
                 return;
             }
 
-            _logger.LogTrace($"Received {nameof(ProjectWorkspaceState)} with {workspaceState.TagHelpers.Length} tag helper(s) for '{key}'");
+            _logger.LogTrace($"Received {nameof(ProjectWorkspaceState)} with {workspaceState.TagHelpers.Count} tag helper(s) for '{key}'");
 
             await _projectManager
                 .UpdateAsync(
@@ -172,7 +172,7 @@ await _projectManager
                             return;
                         }
 
-                        logger.LogTrace($"Updating project with {workspaceState.TagHelpers.Length} tag helper(s) for '{projectKey}'");
+                        logger.LogTrace($"Updating project with {workspaceState.TagHelpers.Count} tag helper(s) for '{projectKey}'");
 
                         var projectSnapshot = updater.GetRequiredProject(projectKey);
                         var hostProject = projectSnapshot.HostProject with { Configuration = configuration };
@@ -290,7 +290,7 @@ private void ReleaseSemaphore(ProjectKey projectKey)
 
         _telemetryReporter.ReportEvent("taghelperresolve/begin", Severity.Normal,
             new("id", telemetryId),
-            new("tagHelperCount", projectSnapshot.ProjectWorkspaceState.TagHelpers.Length));
+            new("tagHelperCount", projectSnapshot.ProjectWorkspaceState.TagHelpers.Count));
 
         try
         {
@@ -317,7 +317,7 @@ private void ReleaseSemaphore(ProjectKey projectKey)
             // Don't report success if the call failed.
             // If the ImmutableArray that was returned is default, then the call failed.
 
-            if (tagHelpers.IsDefault)
+            if (tagHelpers is null)
             {
                 _telemetryReporter.ReportEvent("taghelperresolve/end", Severity.Normal,
                 new("id", telemetryId),
@@ -335,14 +335,14 @@ Tag helper discovery failed.
                 new("id", telemetryId),
                 new("ellapsedms", watch.ElapsedMilliseconds),
                 new("result", "success"),
-                new("tagHelperCount", tagHelpers.Length));
+                new("tagHelperCount", tagHelpers.Count));
 
             _logger.LogInformation($"""
                 Resolved tag helpers for project in {watch.ElapsedMilliseconds} ms.
                 Project: {projectSnapshot.FilePath}
                 """);
 
-            return (ProjectWorkspaceState.Create(tagHelpers), configuration);
+            return (ProjectWorkspaceState.Create([.. tagHelpers]), configuration);
         }
         catch (OperationCanceledException)
         {
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Documents/EditorDocumentManagerListener.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Documents/EditorDocumentManagerListener.cs
index 0a22e87400e..2b5a2ae5f96 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Documents/EditorDocumentManagerListener.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Documents/EditorDocumentManagerListener.cs
@@ -256,7 +256,7 @@ private Task Document_OpenedAsync(object sender, CancellationToken cancellationT
                             "fallbackproject/documentopen",
                             Severity.Normal,
                             new Property("document.count", project.DocumentCount),
-                            new Property("taghelper.count", project.ProjectWorkspaceState.TagHelpers.Length));
+                            new Property("taghelper.count", project.ProjectWorkspaceState.TagHelpers.Count));
                     }
 
                     updater.OpenDocument(document.ProjectKey, document.DocumentFilePath, document.EditorTextContainer!.CurrentText);
diff --git a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Completion/LegacyTagHelperCompletionService.cs b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Completion/LegacyTagHelperCompletionService.cs
index 41f502d3196..f35d52cd32e 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Completion/LegacyTagHelperCompletionService.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Completion/LegacyTagHelperCompletionService.cs
@@ -20,6 +20,9 @@ namespace Microsoft.VisualStudio.LegacyEditor.Razor.Completion;
 [Export(typeof(ITagHelperCompletionService))]
 internal sealed class LegacyTagHelperCompletionService : ITagHelperCompletionService
 {
+    private static readonly HashSetPool<TagHelperDescriptor> s_shortNameSetPool =
+        HashSetPool<TagHelperDescriptor>.Create(ShortNameToFullyQualifiedComparer.Instance);
+
     private static readonly HashSet<TagHelperDescriptor> s_emptyHashSet = new();
 
     // This API attempts to understand a users context as they're typing in a Razor file to provide TagHelper based attribute IntelliSense.
@@ -45,8 +48,13 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
             StringComparer.OrdinalIgnoreCase);
 
         var documentContext = completionContext.DocumentContext;
-        var descriptorsForTag = TagHelperFacts.GetTagHelpersGivenTag(documentContext, completionContext.CurrentTagName, completionContext.CurrentParentTagName);
-        if (descriptorsForTag.Length == 0)
+
+        var tagHelpersForTag = TagHelperFacts.GetTagHelpersGivenTag(
+            documentContext,
+            completionContext.CurrentTagName,
+            completionContext.CurrentParentTagName);
+
+        if (tagHelpersForTag.IsEmpty)
         {
             // If the current tag has no possible descriptors then we can't have any additional attributes.
             return AttributeCompletionResult.Create(attributeCompletions);
@@ -64,9 +72,9 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
 
         using var _ = HashSetPool<TagHelperDescriptor>.GetPooledObject(out var applicableDescriptors);
 
-        if (applicableTagHelperBinding is { Descriptors: var descriptors })
+        if (applicableTagHelperBinding is { TagHelpers: var tagHelpers })
         {
-            applicableDescriptors.UnionWith(descriptors);
+            applicableDescriptors.UnionWith(tagHelpers);
         }
 
         var unprefixedTagName = completionContext.CurrentTagName[prefix.Length..];
@@ -78,11 +86,11 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
             attributeCompletions.Clear();
         }
 
-        foreach (var descriptor in descriptorsForTag)
+        foreach (var tagHelper in tagHelpersForTag)
         {
-            if (applicableDescriptors.Contains(descriptor))
+            if (applicableDescriptors.Contains(tagHelper))
             {
-                foreach (var attributeDescriptor in descriptor.BoundAttributes)
+                foreach (var attributeDescriptor in tagHelper.BoundAttributes)
                 {
                     if (!attributeDescriptor.Name.IsNullOrEmpty())
                     {
@@ -98,7 +106,7 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
             else
             {
                 var htmlNameToBoundAttribute = new Dictionary<string, BoundAttributeDescriptor>(StringComparer.OrdinalIgnoreCase);
-                foreach (var attributeDescriptor in descriptor.BoundAttributes)
+                foreach (var attributeDescriptor in tagHelper.BoundAttributes)
                 {
                     if (attributeDescriptor.Name != null)
                     {
@@ -111,7 +119,7 @@ public AttributeCompletionResult GetAttributeCompletions(AttributeCompletionCont
                     }
                 }
 
-                foreach (var rule in descriptor.TagMatchingRules)
+                foreach (var rule in tagHelper.TagMatchingRules)
                 {
                     foreach (var requiredAttribute in rule.Attributes)
                     {
@@ -178,16 +186,21 @@ public ElementCompletionResult GetElementCompletions(ElementCompletionContext co
             _ => new HashSet<TagHelperDescriptor>(),
             StringComparer.Ordinal);
 
-        var catchAllDescriptors = new HashSet<TagHelperDescriptor>();
+        var catchAllTagHelpers = new HashSet<TagHelperDescriptor>();
         var prefix = completionContext.DocumentContext.Prefix ?? string.Empty;
-        var possibleChildDescriptors = TagHelperFacts.GetTagHelpersGivenParent(completionContext.DocumentContext, completionContext.ContainingTagName);
-        possibleChildDescriptors = FilterFullyQualifiedCompletions(possibleChildDescriptors);
-        foreach (var possibleDescriptor in possibleChildDescriptors)
+
+        var possibleChildTagHelpers = TagHelperFacts.GetTagHelpersGivenParent(
+            completionContext.DocumentContext,
+            completionContext.ContainingTagName);
+
+        possibleChildTagHelpers = FilterFullyQualifiedTagHelpers(possibleChildTagHelpers);
+
+        foreach (var possibleChildTagHelper in possibleChildTagHelpers)
         {
             var addRuleCompletions = false;
-            var outputHint = possibleDescriptor.TagOutputHint;
+            var outputHint = possibleChildTagHelper.TagOutputHint;
 
-            foreach (var rule in possibleDescriptor.TagMatchingRules)
+            foreach (var rule in possibleChildTagHelper.TagMatchingRules)
             {
                 if (!TagHelperMatchingConventions.SatisfiesParentTag(rule, completionContext.ContainingTagName.AsSpanOrDefault()))
                 {
@@ -196,7 +209,7 @@ public ElementCompletionResult GetElementCompletions(ElementCompletionContext co
 
                 if (rule.TagName == TagHelperMatchingConventions.ElementCatchAllName)
                 {
-                    catchAllDescriptors.Add(possibleDescriptor);
+                    catchAllTagHelpers.Add(possibleChildTagHelper);
                 }
                 else if (elementCompletions.ContainsKey(rule.TagName))
                 {
@@ -221,14 +234,14 @@ public ElementCompletionResult GetElementCompletions(ElementCompletionContext co
 
                 if (addRuleCompletions)
                 {
-                    UpdateCompletions(prefix + rule.TagName, possibleDescriptor);
+                    UpdateCompletions(prefix + rule.TagName, possibleChildTagHelper);
                 }
             }
         }
 
         // We needed to track all catch-alls and update their completions after all other completions have been completed.
         // This way, any TagHelper added completions will also have catch-alls listed under their entries.
-        foreach (var catchAllDescriptor in catchAllDescriptors)
+        foreach (var catchAllDescriptor in catchAllTagHelpers)
         {
             foreach (var completionTagName in elementCompletions.Keys)
             {
@@ -290,17 +303,17 @@ private void AddAllowedChildrenCompletions(
             return;
         }
 
-        foreach (var descriptor in binding.Descriptors)
+        foreach (var tagHelper in binding.TagHelpers)
         {
-            foreach (var childTag in descriptor.AllowedChildTags)
+            foreach (var childTag in tagHelper.AllowedChildTags)
             {
                 var prefixedName = string.Concat(prefix, childTag.Name);
-                var descriptors = TagHelperFacts.GetTagHelpersGivenTag(
+                var tagHelpersForTag = TagHelperFacts.GetTagHelpersGivenTag(
                     completionContext.DocumentContext,
                     prefixedName,
                     completionContext.ContainingTagName);
 
-                if (descriptors.Length == 0)
+                if (tagHelpersForTag.IsEmpty)
                 {
                     if (!elementCompletions.ContainsKey(prefixedName))
                     {
@@ -316,47 +329,33 @@ private void AddAllowedChildrenCompletions(
                     elementCompletions[prefixedName] = existingRuleDescriptors;
                 }
 
-                existingRuleDescriptors.AddRange(descriptors);
+                existingRuleDescriptors.UnionWith(tagHelpersForTag);
             }
         }
     }
 
-    private static ImmutableArray<TagHelperDescriptor> FilterFullyQualifiedCompletions(ImmutableArray<TagHelperDescriptor> possibleChildDescriptors)
+    private static TagHelperCollection FilterFullyQualifiedTagHelpers(TagHelperCollection tagHelpers)
     {
-        // Iterate once through the list to tease apart fully qualified and short name TagHelpers
-        using var fullyQualifiedTagHelpers = new PooledArrayBuilder<TagHelperDescriptor>();
-        var shortNameTagHelpers = new HashSet<TagHelperDescriptor>(ShortNameToFullyQualifiedComparer.Instance);
+        // We want to filter 'tagHelpers' and remove any tag helpers that require a fully-qualified name match
+        // but have a short name match present.
 
-        foreach (var descriptor in possibleChildDescriptors)
-        {
-            if (descriptor.IsFullyQualifiedNameMatch)
-            {
-                fullyQualifiedTagHelpers.Add(descriptor);
-            }
-            else
-            {
-                shortNameTagHelpers.Add(descriptor);
-            }
-        }
+        // First, collect all "short name" tag helpers, i.e. those that do not require a fully qualified name match.
+        using var _ = s_shortNameSetPool.GetPooledObject(out var shortNameSet);
 
-        // Re-combine the short named & fully qualified TagHelpers but filter out any fully qualified TagHelpers that have a short
-        // named representation already.
-        using var filteredList = new PooledArrayBuilder<TagHelperDescriptor>(capacity: shortNameTagHelpers.Count);
-        filteredList.AddRange(shortNameTagHelpers);
-
-        foreach (var fullyQualifiedTagHelper in fullyQualifiedTagHelpers)
+        foreach (var tagHelper in tagHelpers)
         {
-            if (!shortNameTagHelpers.Contains(fullyQualifiedTagHelper))
+            if (!tagHelper.IsFullyQualifiedNameMatch)
             {
-                // Unimported completion item that isn't represented in a short named form.
-                filteredList.Add(fullyQualifiedTagHelper);
-            }
-            else
-            {
-                // There's already a shortname variant of this item, don't include it.
+                shortNameSet.Add(tagHelper);
             }
         }
 
-        return filteredList.ToImmutableAndClear();
+        return tagHelpers.Where(shortNameSet, static (tagHelper, shortNameSet) =>
+        {
+            // We want to keep tag helpers that either:
+            // 1. Do not require a fully qualified name match (i.e., short name tag helpers).
+            // 2. Are fully qualified tag helpers that do not have a corresponding short name tag helper.
+            return !tagHelper.IsFullyQualifiedNameMatch || !shortNameSet.Contains(tagHelper);
+        });
     }
 }
diff --git a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/EphemeralProjectSnapshot.cs b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/EphemeralProjectSnapshot.cs
index 4a51b790441..32d6d65f18f 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/EphemeralProjectSnapshot.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/EphemeralProjectSnapshot.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Immutable;
 using System.IO;
 using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.Language;
@@ -26,7 +25,7 @@ internal sealed class EphemeralProjectSnapshot(IProjectEngineFactoryProvider pro
     public RazorConfiguration Configuration => FallbackRazorConfiguration.Latest;
     public string? RootNamespace => null;
     public LanguageVersion CSharpLanguageVersion => LanguageVersion.Default;
-    public ImmutableArray<TagHelperDescriptor> TagHelpers => [];
+    public TagHelperCollection TagHelpers => [];
 
     public RazorProjectEngine GetProjectEngine()
         => _projectEngine.Value;
diff --git a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/IVisualStudioDocumentTracker.cs b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/IVisualStudioDocumentTracker.cs
index 7f936343cf8..ae3226ac284 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/IVisualStudioDocumentTracker.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/IVisualStudioDocumentTracker.cs
@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem.Legacy;
 using Microsoft.CodeAnalysis.Razor.Settings;
@@ -16,7 +15,7 @@ internal interface IVisualStudioDocumentTracker
 {
     RazorConfiguration? Configuration { get; }
     ClientSpaceSettings EditorSettings { get; }
-    ImmutableArray<TagHelperDescriptor> TagHelpers { get; }
+    TagHelperCollection TagHelpers { get; }
     bool IsSupportedProject { get; }
     string FilePath { get; }
     string ProjectPath { get; }
diff --git a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Parsing/VisualStudioRazorParser.cs b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Parsing/VisualStudioRazorParser.cs
index 8945148d6de..6cd75e68db6 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Parsing/VisualStudioRazorParser.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/Parsing/VisualStudioRazorParser.cs
@@ -581,18 +581,11 @@ private void CompleteCodeDocumentRequestsForSnapshot(RazorCodeDocument codeDocum
         }
     }
 
-    private class VisualStudioTagHelperFeature : RazorEngineFeatureBase, ITagHelperFeature
+    private class VisualStudioTagHelperFeature(TagHelperCollection tagHelpers) : RazorEngineFeatureBase, ITagHelperFeature
     {
-        private readonly IReadOnlyList<TagHelperDescriptor>? _tagHelpers;
-
-        public VisualStudioTagHelperFeature(IReadOnlyList<TagHelperDescriptor>? tagHelpers)
-        {
-            _tagHelpers = tagHelpers;
-        }
-
-        public IReadOnlyList<TagHelperDescriptor> GetDescriptors(CancellationToken cancellationToken = default)
+        public TagHelperCollection GetTagHelpers(CancellationToken cancellationToken = default)
         {
-            return _tagHelpers ?? [];
+            return tagHelpers;
         }
     }
 
diff --git a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/VisualStudioDocumentTracker.cs b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/VisualStudioDocumentTracker.cs
index 0569e316961..d7d828da149 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/VisualStudioDocumentTracker.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LegacyEditor.Razor/VisualStudioDocumentTracker.cs
@@ -3,8 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor;
@@ -70,7 +68,7 @@ public VisualStudioDocumentTracker(
 
     public ClientSpaceSettings EditorSettings => _workspaceEditorSettings.Current.ClientSpaceSettings;
 
-    public ImmutableArray<TagHelperDescriptor> TagHelpers
+    public TagHelperCollection TagHelpers
         => _projectSnapshot is { TagHelpers: var tagHelpers }
             ? tagHelpers
             : [];
@@ -218,7 +216,7 @@ internal void ProjectManager_Changed(object sender, ProjectChangeEventArgs e)
                     OnContextChangedAsync(ContextChangeKind.ProjectChanged).Forget();
 
                     if (e.Older is not ILegacyProjectSnapshot older ||
-                        !older.TagHelpers.SequenceEqual(newer.TagHelpers))
+                        !older.TagHelpers.Equals(newer.TagHelpers))
                     {
                         OnContextChangedAsync(ContextChangeKind.TagHelpersChanged).Forget();
                     }
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor.Test/RazorSyntaxFactsServiceTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor.Test/RazorSyntaxFactsServiceTest.cs
index 522bc96bcc0..b455ba332b3 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor.Test/RazorSyntaxFactsServiceTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.LegacyEditor.Test/RazorSyntaxFactsServiceTest.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Xunit;
 using Xunit.Abstractions;
@@ -98,7 +97,7 @@ private IRazorCodeDocument GetCodeDocument(string source)
         var sourceDocument = TestRazorSourceDocument.Create(source, normalizeNewLines: true);
         var importDocument = TestRazorSourceDocument.Create("@addTagHelper *, TestAssembly", filePath: "import.cshtml", relativePath: "import.cshtml");
 
-        var codeDocument = engine.ProcessDesignTime(sourceDocument, RazorFileKind.Legacy, importSources: ImmutableArray.Create(importDocument), new[] { taghelper });
+        var codeDocument = engine.ProcessDesignTime(sourceDocument, RazorFileKind.Legacy, importSources: [importDocument], [taghelper]);
 
         return RazorWrapperFactory.WrapCodeDocument(codeDocument);
     }
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/AutoInsert/RazorOnAutoInsertProviderTestBase.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/AutoInsert/RazorOnAutoInsertProviderTestBase.cs
index c10d481c6fc..f591a868349 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/AutoInsert/RazorOnAutoInsertProviderTestBase.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/AutoInsert/RazorOnAutoInsertProviderTestBase.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common.LanguageServer;
 using Microsoft.CodeAnalysis.Razor.AutoInsert;
@@ -22,7 +21,7 @@ protected void RunAutoInsertTest(
         string expected,
         bool enableAutoClosingTags = true,
         RazorFileKind? fileKind = null,
-        ImmutableArray<TagHelperDescriptor> tagHelpers = default)
+        TagHelperCollection? tagHelpers = null)
     {
         // Arrange
         TestFileMarkupParser.GetPosition(input, out input, out var location);
@@ -54,11 +53,11 @@ private static SourceText ApplyEdit(SourceText source, TextEdit edit)
     private static RazorCodeDocument CreateCodeDocument(
         SourceText text,
         string path,
-        ImmutableArray<TagHelperDescriptor> tagHelpers,
+        TagHelperCollection? tagHelpers,
         RazorFileKind? fileKind = null)
     {
         var fileKindValue = fileKind ?? RazorFileKind.Component;
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         var sourceDocument = RazorSourceDocument.Create(text, RazorSourceDocumentProperties.Create(path, path));
         var projectEngine = RazorProjectEngine.Create(builder =>
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/CSharpCodeActionProviderTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/CSharpCodeActionProviderTest.cs
index 169222c6cb7..ffae1703b2f 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/CSharpCodeActionProviderTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/CSharpCodeActionProviderTest.cs
@@ -307,11 +307,11 @@ private static RazorCodeActionContext CreateRazorCodeActionContext(
         bool supportsFileCreation = true,
         bool supportsCodeActionResolve = true)
     {
-        var tagHelpers = ImmutableArray<TagHelperDescriptor>.Empty;
+        var tagHelpers = TagHelperCollection.Empty;
         var sourceDocument = TestRazorSourceDocument.Create(text, filePath: filePath, relativePath: filePath);
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelpers);
+            builder.SetTagHelpers(tagHelpers);
 
             builder.ConfigureParserOptions(builder =>
             {
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/TypeAccessibilityCodeActionProviderTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/TypeAccessibilityCodeActionProviderTest.cs
index b21cce5223a..a1524cbafe0 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/TypeAccessibilityCodeActionProviderTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CSharp/TypeAccessibilityCodeActionProviderTest.cs
@@ -431,12 +431,12 @@ private static RazorCodeActionContext CreateRazorCodeActionContext(
         var fullyQualifiedComponent = TagHelperDescriptorBuilder.CreateComponent("Fully.Qualified.Component", "TestAssembly");
         fullyQualifiedComponent.TagMatchingRule(rule => rule.TagName = "Fully.Qualified.Component");
 
-        var tagHelpers = ImmutableArray.Create(shortComponent.Build(), fullyQualifiedComponent.Build());
+        TagHelperCollection tagHelpers = [shortComponent.Build(), fullyQualifiedComponent.Build()];
 
         var sourceDocument = TestRazorSourceDocument.Create(text, filePath: filePath, relativePath: filePath);
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelpers);
+            builder.SetTagHelpers(tagHelpers);
             builder.AddDirective(InjectDirective.Directive);
 
             builder.ConfigureParserOptions(builder =>
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs
index b4fa852f71d..da59332bea5 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTest.NetFx.cs
@@ -11,8 +11,6 @@
 using Microsoft.CodeAnalysis.Razor.Formatting;
 using Microsoft.CodeAnalysis.Razor.Protocol;
 using Microsoft.CodeAnalysis.Testing;
-using Microsoft.CodeAnalysis.Text;
-using Roslyn.Test.Utilities;
 using Xunit;
 using Xunit.Abstractions;
 
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTestBase.NetFx.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTestBase.NetFx.cs
index 02ab7f1c1f6..7b8569c7da5 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTestBase.NetFx.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/CodeActionEndToEndTestBase.NetFx.cs
@@ -288,7 +288,7 @@ internal async Task<TextDocumentEdit[]> GetEditsAsync(
         return documentEdits;
     }
 
-    internal static ImmutableArray<TagHelperDescriptor> CreateTagHelperDescriptors()
+    internal static TagHelperCollection CreateTagHelperDescriptors()
     {
         return [.. BuildTagHelpers()];
 
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Html/HtmlCodeActionProviderTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Html/HtmlCodeActionProviderTest.cs
index def2a9572d3..9d91f6bdd84 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Html/HtmlCodeActionProviderTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Html/HtmlCodeActionProviderTest.cs
@@ -139,11 +139,11 @@ private static RazorCodeActionContext CreateRazorCodeActionContext(
         bool supportsFileCreation = true,
         bool supportsCodeActionResolve = true)
     {
-        var tagHelpers = ImmutableArray<TagHelperDescriptor>.Empty;
+        var tagHelpers = TagHelperCollection.Empty;
         var sourceDocument = TestRazorSourceDocument.Create(text, filePath: filePath, relativePath: filePath);
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelpers);
+            builder.SetTagHelpers(tagHelpers);
 
             builder.ConfigureParserOptions(builder =>
             {
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Razor/ComponentAccessibilityCodeActionProviderTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Razor/ComponentAccessibilityCodeActionProviderTest.cs
index ead20806c3e..f55f98b44e9 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Razor/ComponentAccessibilityCodeActionProviderTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/CodeActions/Razor/ComponentAccessibilityCodeActionProviderTest.cs
@@ -466,12 +466,12 @@ private static RazorCodeActionContext CreateRazorCodeActionContext(
         fullyQualifiedGenericComponent.CaseSensitive = true;
         fullyQualifiedGenericComponent.TagMatchingRule(rule => rule.TagName = "Fully.Qualified.GenericComponent");
 
-        var tagHelpers = ImmutableArray.Create(shortComponent.Build(), fullyQualifiedComponent.Build(), shortGenericComponent.Build(), fullyQualifiedGenericComponent.Build());
+        TagHelperCollection tagHelpers = [shortComponent.Build(), fullyQualifiedComponent.Build(), shortGenericComponent.Build(), fullyQualifiedGenericComponent.Build()];
 
         var sourceDocument = TestRazorSourceDocument.Create(text, filePath: filePath, relativePath: filePath);
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
-            builder.AddTagHelpers(tagHelpers);
+            builder.SetTagHelpers(tagHelpers);
 
             builder.ConfigureParserOptions(builder =>
             {
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperCompletionProviderTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperCompletionProviderTest.cs
index 29cc3fc059b..e0e4ccefff1 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperCompletionProviderTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperCompletionProviderTest.cs
@@ -4,7 +4,6 @@
 #nullable disable
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.Test.Common;
@@ -561,7 +560,7 @@ public void GetCompletionAt_AtAttributeEdge_IndexerBoolAttribute_ReturnsCompleti
                 <test $$/>
                 """,
             isRazorFile: false,
-            tagHelpers: ImmutableArray.Create(tagHelper.Build()));
+            tagHelpers: [tagHelper.Build()]);
 
         // Act
         var completions = service.GetCompletionItems(context);
@@ -604,7 +603,7 @@ public void GetCompletionAt_AtAttributeEdge_IndexerAttribute_ReturnsCompletions(
                 <test $$/>
                 """,
             isRazorFile: false,
-            tagHelpers: ImmutableArray.Create(tagHelper.Build()));
+            tagHelpers: [tagHelper.Build()]);
 
         // Act
         var completions = service.GetCompletionItems(context);
@@ -971,17 +970,17 @@ public void GetCompletionAt_ComponentWithEditorRequiredAttributes_SnippetsSuppor
                 """,
             isRazorFile: true,
             options,
-            tagHelpers: ImmutableArray.Create(componentBuilder.Build()));
+            tagHelpers: [componentBuilder.Build()]);
 
         // Act
         var completions = service.GetCompletionItems(context);
 
         // Assert - should have two completions: regular and snippet
         Assert.Equal(2, completions.Length);
-        
+
         RazorCompletionItem regularCompletion = null;
         RazorCompletionItem snippetCompletion = null;
-        
+
         foreach (var completion in completions)
         {
             if (completion.DisplayText == "ComponentWithRequiredParams")
@@ -993,11 +992,11 @@ public void GetCompletionAt_ComponentWithEditorRequiredAttributes_SnippetsSuppor
                 snippetCompletion = completion;
             }
         }
-        
+
         Assert.NotNull(regularCompletion);
         Assert.False(regularCompletion.IsSnippet);
         Assert.Equal("ComponentWithRequiredParams", regularCompletion.InsertText);
-        
+
         Assert.NotNull(snippetCompletion);
         Assert.True(snippetCompletion.IsSnippet);
         Assert.Contains("RequiredParam1", snippetCompletion.InsertText);
@@ -1036,7 +1035,7 @@ public void GetCompletionAt_ComponentWithEditorRequiredAttributes_SnippetsNotSup
                 """,
             isRazorFile: true,
             options,
-            tagHelpers: ImmutableArray.Create(componentBuilder.Build()));
+            tagHelpers: [componentBuilder.Build()]);
 
         // Act
         var completions = service.GetCompletionItems(context);
@@ -1074,7 +1073,7 @@ public void GetCompletionAt_ComponentWithNoEditorRequiredAttributes_SnippetsSupp
                 """,
             isRazorFile: true,
             options,
-            tagHelpers: ImmutableArray.Create(componentBuilder.Build()));
+            tagHelpers: [componentBuilder.Build()]);
 
         // Act
         var completions = service.GetCompletionItems(context);
@@ -1086,9 +1085,13 @@ public void GetCompletionAt_ComponentWithNoEditorRequiredAttributes_SnippetsSupp
         Assert.Equal("ComponentWithoutRequired", completion.InsertText);
     }
 
-    private static RazorCompletionContext CreateRazorCompletionContext(string markup, bool isRazorFile, RazorCompletionOptions options = default, ImmutableArray<TagHelperDescriptor> tagHelpers = default)
+    private static RazorCompletionContext CreateRazorCompletionContext(
+        string markup,
+        bool isRazorFile,
+        RazorCompletionOptions options = default,
+        TagHelperCollection tagHelpers = null)
     {
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         TestFileMarkupParser.GetPosition(markup, out var documentContent, out var position);
         var codeDocument = CreateCodeDocument(documentContent, isRazorFile, tagHelpers);
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperServiceTestBase.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperServiceTestBase.cs
index 778cfcf1672..14eb54161f9 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperServiceTestBase.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Completion/TagHelperServiceTestBase.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common;
 using Microsoft.AspNetCore.Razor.Test.Common.LanguageServer;
@@ -11,14 +10,14 @@ namespace Microsoft.AspNetCore.Razor.LanguageServer.Completion;
 
 public abstract class TagHelperServiceTestBase(ITestOutputHelper testOutput) : LanguageServerTestBase(testOutput)
 {
-    protected static ImmutableArray<TagHelperDescriptor> DefaultTagHelpers => SimpleTagHelpers.Default;
+    protected static TagHelperCollection DefaultTagHelpers => SimpleTagHelpers.Default;
 
     protected static string GetFileName(bool isRazorFile)
         => RazorCodeDocumentFactory.GetFileName(isRazorFile);
 
-    protected static RazorCodeDocument CreateCodeDocument(string text, bool isRazorFile, params ImmutableArray<TagHelperDescriptor> tagHelpers)
+    protected static RazorCodeDocument CreateCodeDocument(string text, bool isRazorFile, params TagHelperCollection tagHelpers)
         => RazorCodeDocumentFactory.CreateCodeDocument(text, isRazorFile, tagHelpers);
 
-    protected static RazorCodeDocument CreateCodeDocument(string text, string filePath, params ImmutableArray<TagHelperDescriptor> tagHelpers)
+    protected static RazorCodeDocument CreateCodeDocument(string text, string filePath, params TagHelperCollection tagHelpers)
         => RazorCodeDocumentFactory.CreateCodeDocument(text, filePath, tagHelpers);
 }
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/CodeDirectiveFormattingTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/CodeDirectiveFormattingTest.cs
index 1aadee43d1e..389732eca72 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/CodeDirectiveFormattingTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/CodeDirectiveFormattingTest.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common;
@@ -70,7 +69,7 @@ await RunFormattingTestAsync(
                         private IEnumerable<int> _items = new[] { 1, 2, 3, 4, 5 };
                     }
                     """,
-            tagHelpers: GetComponentWithCascadingTypeParameter());
+            tagHelpers: [.. GetComponentWithCascadingTypeParameter()]);
     }
 
     [FormattingTestFact]
@@ -120,7 +119,7 @@ await RunFormattingTestAsync(
                         private IEnumerable<int> _items = new[] { 1, 2, 3, 4, 5 };
                     }
                     """,
-            tagHelpers: GetComponentWithCascadingTypeParameter());
+            tagHelpers: [.. GetComponentWithCascadingTypeParameter()]);
     }
 
     [FormattingTestFact]
@@ -160,10 +159,10 @@ await RunFormattingTestAsync(
                         private IEnumerable<long> _items2 = new long[] { 1, 2, 3, 4, 5 };
                     }
                     """,
-            tagHelpers: GetComponentWithTwoCascadingTypeParameter());
+            tagHelpers: [.. GetComponentWithTwoCascadingTypeParameter()]);
     }
 
-    private ImmutableArray<TagHelperDescriptor> GetComponentWithCascadingTypeParameter()
+    private TagHelperCollection GetComponentWithCascadingTypeParameter()
     {
         var input = """
                 @using System.Collections.Generic
@@ -185,7 +184,7 @@ @attribute [CascadingTypeParameter(nameof(TItem))]
         return generated.CodeDocument.GetRequiredTagHelperContext().TagHelpers;
     }
 
-    private ImmutableArray<TagHelperDescriptor> GetComponentWithTwoCascadingTypeParameter()
+    private TagHelperCollection GetComponentWithTwoCascadingTypeParameter()
     {
         var input = """
                 @using System.Collections.Generic
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingContentValidationPassTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingContentValidationPassTest.cs
index a9121c3d38e..86947910032 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingContentValidationPassTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingContentValidationPassTest.cs
@@ -97,11 +97,11 @@ private static FormattingContext CreateFormattingContext
     private static (RazorCodeDocument, IDocumentSnapshot) CreateCodeDocumentAndSnapshot(
         SourceText text,
         string path,
-        ImmutableArray<TagHelperDescriptor> tagHelpers = default,
+        TagHelperCollection? tagHelpers = null,
         RazorFileKind? fileKind = null)
     {
         var fileKindValue = fileKind ?? RazorFileKind.Component;
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         var sourceDocument = RazorSourceDocument.Create(text, RazorSourceDocumentProperties.Create(path, path));
         var projectEngine = RazorProjectEngine.Create(builder =>
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingDiagnosticValidationPassTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingDiagnosticValidationPassTest.cs
index ad52c5cbd3f..6cb25b593c2 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingDiagnosticValidationPassTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingDiagnosticValidationPassTest.cs
@@ -95,11 +95,11 @@ private static FormattingContext CreateFormattingContext(
     private static (RazorCodeDocument, IDocumentSnapshot) CreateCodeDocumentAndSnapshot(
         SourceText text,
         string path,
-        ImmutableArray<TagHelperDescriptor> tagHelpers = default,
+        TagHelperCollection? tagHelpers = null,
         RazorFileKind? fileKind = null)
     {
         var fileKindValue = fileKind ?? RazorFileKind.Component;
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         var sourceDocument = RazorSourceDocument.Create(text, RazorSourceDocumentProperties.Create(path, path));
         var projectEngine = RazorProjectEngine.Create(builder =>
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingTestBase.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingTestBase.cs
index be252e20a17..c0a706c7b37 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingTestBase.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/FormattingTestBase.cs
@@ -36,7 +36,7 @@ namespace Microsoft.AspNetCore.Razor.LanguageServer.Formatting;
 
 public abstract class FormattingTestBase : RazorToolingIntegrationTestBase
 {
-    private static readonly AsyncLazy<ImmutableArray<TagHelperDescriptor>> s_standardTagHelpers = AsyncLazy.Create(GetStandardTagHelpersAsync);
+    private static readonly AsyncLazy<TagHelperCollection> s_standardTagHelpers = AsyncLazy.Create(GetStandardTagHelpersAsync);
 
     private readonly HtmlFormattingService _htmlFormattingService;
     private readonly FormattingTestContext _context;
@@ -56,7 +56,7 @@ private protected async Task RunFormattingTestAsync(
         int tabSize = 4,
         bool insertSpaces = true,
         RazorFileKind? fileKind = null,
-        ImmutableArray<TagHelperDescriptor> tagHelpers = default,
+        TagHelperCollection? tagHelpers = null,
         bool allowDiagnostics = false,
         bool codeBlockBraceOnNextLine = false,
         bool inGlobalNamespace = false,
@@ -78,7 +78,7 @@ private async Task RunFormattingTestInternalAsync(
         int tabSize,
         bool insertSpaces,
         RazorFileKind? fileKind,
-        ImmutableArray<TagHelperDescriptor> tagHelpers,
+        TagHelperCollection? tagHelpers,
         bool allowDiagnostics,
         RazorLSPOptions? razorLSPOptions,
         bool inGlobalNamespace,
@@ -87,7 +87,7 @@ private async Task RunFormattingTestInternalAsync(
     {
         // Arrange
         var fileKindValue = fileKind ?? RazorFileKind.Component;
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         TestFileMarkupParser.GetSpans(input, out input, out ImmutableArray<TextSpan> spans);
 
@@ -96,7 +96,7 @@ private async Task RunFormattingTestInternalAsync(
             ? null
             : source.GetLinePositionSpan(spans.Single());
 
-        tagHelpers = tagHelpers.AddRange(await s_standardTagHelpers.GetValueAsync(DisposalToken));
+        tagHelpers = TagHelperCollection.Merge(tagHelpers, await s_standardTagHelpers.GetValueAsync(DisposalToken));
 
         var path = "file:///path/to/Document." + fileKindValue.ToString();
         var uri = new Uri(path);
@@ -229,7 +229,7 @@ private protected async Task RunOnTypeFormattingTestAsync(
     private (RazorCodeDocument, IDocumentSnapshot) CreateCodeDocumentAndSnapshot(
         SourceText text,
         string path,
-        ImmutableArray<TagHelperDescriptor> tagHelpers,
+        TagHelperCollection tagHelpers,
         RazorFileKind? fileKind = null,
         bool allowDiagnostics = false,
         bool inGlobalNamespace = false)
@@ -303,7 +303,7 @@ internal static IDocumentSnapshot CreateDocumentSnapshot(
         RazorProjectEngine projectEngine,
         ImmutableArray<IDocumentSnapshot> imports,
         ImmutableArray<RazorSourceDocument> importDocuments,
-        ImmutableArray<TagHelperDescriptor> tagHelpers,
+        TagHelperCollection tagHelpers,
         bool inGlobalNamespace)
     {
         var projectKey = new ProjectKey(Path.Combine(path, "obj"));
@@ -354,7 +354,7 @@ internal static IDocumentSnapshot CreateDocumentSnapshot(
         return snapshotMock.Object;
     }
 
-    private static async Task<ImmutableArray<TagHelperDescriptor>> GetStandardTagHelpersAsync(CancellationToken cancellationToken)
+    private static async Task<TagHelperCollection> GetStandardTagHelpersAsync(CancellationToken cancellationToken)
     {
         var projectId = ProjectId.CreateNewId();
         var projectInfo = ProjectInfo
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/HtmlFormattingTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/HtmlFormattingTest.cs
index 2a7fa0de08f..23f85daf973 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/HtmlFormattingTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Formatting_NetFx/HtmlFormattingTest.cs
@@ -56,7 +56,7 @@ await RunFormattingTestAsync(
                         }
                     </GridTable>
                     """,
-            tagHelpers: tagHelpers);
+            tagHelpers: [.. tagHelpers]);
     }
 
     [FormattingTestFact]
@@ -80,7 +80,7 @@ await RunFormattingTestAsync(
                         </GridRow>
                     </GridTable>
                     """,
-            tagHelpers: tagHelpers);
+            tagHelpers: [.. tagHelpers]);
     }
 
     [FormattingTestFact]
@@ -102,7 +102,7 @@ await RunFormattingTestAsync(
                         </GridRow>
                     </GridTable>
                     """,
-            tagHelpers: tagHelpers);
+            tagHelpers: [.. tagHelpers]);
     }
 
     [FormattingTestFact]
@@ -124,7 +124,7 @@ await RunFormattingTestAsync(
                         </GridRow>
                     </GridTable>
                     """,
-            tagHelpers: tagHelpers);
+            tagHelpers: [.. tagHelpers]);
     }
 
     [FormattingTestFact]
@@ -150,7 +150,7 @@ await RunFormattingTestAsync(
                         </GridRow>
                     </GridTable>
                     """,
-            tagHelpers: tagHelpers);
+            tagHelpers: [.. tagHelpers]);
     }
 
     [FormattingTestFact]
@@ -198,7 +198,7 @@ await RunFormattingTestAsync(
                         </ChildContent>
                     </GridTable>
                     """,
-            tagHelpers: GetComponents());
+            tagHelpers: [.. GetComponents()]);
     }
 
     [FormattingTestFact]
@@ -260,7 +260,7 @@ await RunFormattingTestAsync(
                         </a_really_long_tag_name>
                     }
                     """,
-            tagHelpers: GetComponents());
+            tagHelpers: [.. GetComponents()]);
     }
 
     [FormattingTestFact(Skip = "Requires fix")]
@@ -284,7 +284,7 @@ await RunFormattingTestAsync(
                         </Component1>;
                     }
                     """,
-            tagHelpers: GetComponents());
+            tagHelpers: [.. GetComponents()]);
     }
 
     [FormattingTestFact]
@@ -312,7 +312,7 @@ await RunFormattingTestAsync(
                         }
                     </Component1>
                     """,
-            tagHelpers: GetComponents());
+            tagHelpers: [.. GetComponents()]);
     }
 
     [FormattingTestFact]
@@ -360,7 +360,7 @@ await RunFormattingTestAsync(
                     </ChildContent>
                     </GridTable>
                     """,
-            tagHelpers: GetComponents());
+            tagHelpers: [.. GetComponents()]);
     }
 
     [FormattingTestFact]
@@ -398,7 +398,7 @@ await RunFormattingTestAsync(
                         }
                     </Select>
                     """,
-            tagHelpers: CreateTagHelpers());
+            tagHelpers: [.. CreateTagHelpers()]);
 
         ImmutableArray<TagHelperDescriptor> CreateTagHelpers()
         {
@@ -480,7 +480,7 @@ await RunFormattingTestAsync(
             allowDiagnostics: true);
     }
 
-    private ImmutableArray<TagHelperDescriptor> GetComponents()
+    private TagHelperCollection GetComponents()
     {
         AdditionalSyntaxTrees.Add(Parse("""
                 using Microsoft.AspNetCore.Components;
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Refactoring/RenameEndpointTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Refactoring/RenameEndpointTest.cs
index 5145ce72968..f31c736913b 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Refactoring/RenameEndpointTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Refactoring/RenameEndpointTest.cs
@@ -327,7 +327,7 @@ public async Task Handle_Rename_ComponentInSameFile()
         // Assert
         Assert.NotNull(result);
         var documentChanges = result.DocumentChanges.AssumeNotNull();
-        Assert.Equal(5, documentChanges.Count());
+        Assert.Equal(4, documentChanges.Count());
 
         // We renamed Component3 to Component5, so we should expect file rename.
         var renameChange = documentChanges.ElementAt(0);
@@ -335,20 +335,14 @@ public async Task Handle_Rename_ComponentInSameFile()
         Assert.Equal(TestPathUtilities.GetUri(s_componentFilePath3), renameFile.OldDocumentUri.GetRequiredParsedUri());
         Assert.Equal(TestPathUtilities.GetUri(s_componentFilePath5), renameFile.NewDocumentUri.GetRequiredParsedUri());
 
-        Assert.Collection(GetTextDocumentEdits(result, startIndex: 1, endIndex: 4),
+        Assert.Collection(GetTextDocumentEdits(result, startIndex: 1, endIndex: 3),
             textDocumentEdit =>
             {
                 Assert.Equal(TestPathUtilities.GetUri(s_componentFilePath4), textDocumentEdit.TextDocument.DocumentUri.GetRequiredParsedUri());
                 Assert.Collection(
                     textDocumentEdit.Edits,
                     AssertTextEdit("Component5", startLine: 1, startCharacter: 1, endLine: 1, endCharacter: 11),
-                    AssertTextEdit("Component5", startLine: 1, startCharacter: 14, endLine: 1, endCharacter: 24));
-            },
-            textDocumentEdit =>
-            {
-                Assert.Equal(TestPathUtilities.GetUri(s_componentFilePath4), textDocumentEdit.TextDocument.DocumentUri.GetRequiredParsedUri());
-                Assert.Collection(
-                    textDocumentEdit.Edits,
+                    AssertTextEdit("Component5", startLine: 1, startCharacter: 14, endLine: 1, endCharacter: 24),
                     AssertTextEdit("Component5", startLine: 2, startCharacter: 1, endLine: 2, endCharacter: 11),
                     AssertTextEdit("Component5", startLine: 2, startCharacter: 14, endLine: 2, endCharacter: 24));
             },
@@ -413,7 +407,7 @@ public async Task Handle_Rename_FullyQualifiedAndNot()
         // Assert
         Assert.NotNull(result);
         var documentChanges = result.DocumentChanges.AssumeNotNull();
-        Assert.Equal(3, documentChanges.Count());
+        Assert.Equal(2, documentChanges.Count());
 
         var renameChange = documentChanges.ElementAt(0);
         Assert.True(renameChange.TryGetThird(out var renameFile));
@@ -426,13 +420,7 @@ public async Task Handle_Rename_FullyQualifiedAndNot()
         Assert.Collection(
             textDocumentEdit.Edits,
             AssertTextEdit("Component5", startLine: 2, startCharacter: 1, endLine: 2, endCharacter: 14),
-            AssertTextEdit("Component5", startLine: 2, startCharacter: 17, endLine: 2, endCharacter: 30));
-
-        var editChange2 = result.DocumentChanges.Value.ElementAt(2);
-        Assert.True(editChange2.TryGetFirst(out var textDocumentEdit2));
-        Assert.Equal(TestPathUtilities.GetUri(s_indexFilePath1), textDocumentEdit2.TextDocument.DocumentUri.GetRequiredParsedUri());
-        Assert.Collection(
-            textDocumentEdit2.Edits,
+            AssertTextEdit("Component5", startLine: 2, startCharacter: 17, endLine: 2, endCharacter: 30),
             AssertTextEdit("Test.Component5", startLine: 3, startCharacter: 1, endLine: 3, endCharacter: 19),
             AssertTextEdit("Test.Component5", startLine: 3, startCharacter: 22, endLine: 3, endCharacter: 40));
     }
@@ -459,7 +447,7 @@ public async Task Handle_Rename_MultipleFileUsages()
         // Assert
         Assert.NotNull(result);
         var documentChanges = result.DocumentChanges.AssumeNotNull();
-        Assert.Equal(5, documentChanges.Count());
+        Assert.Equal(4, documentChanges.Count());
 
         var renameChange = documentChanges.ElementAt(0);
         Assert.True(renameChange.TryGetThird(out var renameFile));
@@ -477,17 +465,18 @@ public async Task Handle_Rename_MultipleFileUsages()
         var editChange2 = documentChanges.ElementAt(2);
         Assert.True(editChange2.TryGetFirst(out var textDocumentEdit2));
         Assert.Equal(TestPathUtilities.GetUri(s_componentFilePath4), textDocumentEdit2.TextDocument.DocumentUri.GetRequiredParsedUri());
-        Assert.Equal(2, textDocumentEdit2.Edits.Length);
+        Assert.Collection(
+            textDocumentEdit.Edits,
+            AssertTextEdit("Component5", 1, 1, 1, 11),
+            AssertTextEdit("Component5", 1, 14, 1, 24));
 
         var editChange3 = documentChanges.ElementAt(3);
         Assert.True(editChange3.TryGetFirst(out var textDocumentEdit3));
-        Assert.Equal(TestPathUtilities.GetUri(s_componentFilePath4), textDocumentEdit3.TextDocument.DocumentUri.GetRequiredParsedUri());
-        Assert.Equal(2, textDocumentEdit3.Edits.Length);
-
-        var editChange4 = documentChanges.ElementAt(4);
-        Assert.True(editChange4.TryGetFirst(out var textDocumentEdit4));
-        Assert.Equal(TestPathUtilities.GetUri(s_componentWithParamFilePath), textDocumentEdit4.TextDocument.DocumentUri.GetRequiredParsedUri());
-        Assert.Equal(2, textDocumentEdit4.Edits.Length);
+        Assert.Equal(TestPathUtilities.GetUri(s_componentWithParamFilePath), textDocumentEdit3.TextDocument.DocumentUri.GetRequiredParsedUri());
+        Assert.Collection(
+            textDocumentEdit.Edits,
+            AssertTextEdit("Component5", 1, 1, 1, 11),
+            AssertTextEdit("Component5", 1, 14, 1, 24));
     }
 
     [Fact]
@@ -617,16 +606,7 @@ public async Task Handle_Rename_SingleServer_DoesNotDelegateForRazor()
         IEditMappingService? editMappingService = null,
         IClientConnection? clientConnection = null)
     {
-        using PooledArrayBuilder<TagHelperDescriptor> builder = [];
-        builder.AddRange(CreateRazorComponentTagHelperDescriptors("First", RootNamespace1, "Component1"));
-        builder.AddRange(CreateRazorComponentTagHelperDescriptors("First", "Test", "Component2"));
-        builder.AddRange(CreateRazorComponentTagHelperDescriptors("Second", RootNamespace2, "Component3"));
-        builder.AddRange(CreateRazorComponentTagHelperDescriptors("Second", RootNamespace2, "Component4"));
-        builder.AddRange(CreateRazorComponentTagHelperDescriptors("First", "Test", "Component1337"));
-        builder.AddRange(CreateRazorComponentTagHelperDescriptors("First", "Test.Components", "Directory1"));
-        builder.AddRange(CreateRazorComponentTagHelperDescriptors("First", "Test.Components", "Directory2"));
-        var tagHelpers = builder.ToImmutable();
-
+        var tagHelpers = CreateRazorComponentTagHelpers();
         var projectManager = CreateProjectSnapshotManager();
 
         var documentContextFactory = new DocumentContextFactory(projectManager, LoggerFactory);
@@ -723,21 +703,36 @@ await projectManager.UpdateAsync(updater =>
         return (endpoint, documentContextFactory);
     }
 
-    private static IEnumerable<TagHelperDescriptor> CreateRazorComponentTagHelperDescriptors(string assemblyName, string namespaceName, string tagName)
+    private static TagHelperCollection CreateRazorComponentTagHelpers()
     {
-        var fullyQualifiedName = $"{namespaceName}.{tagName}";
-        var builder = TagHelperDescriptorBuilder.CreateComponent(fullyQualifiedName, assemblyName);
-        builder.SetTypeName(fullyQualifiedName, namespaceName, tagName);
-        builder.TagMatchingRule(rule => rule.TagName = tagName);
+        using var builder = new TagHelperCollection.RefBuilder();
+        builder.AddRange(CreateRazorComponentTagHelpersCore("First", RootNamespace1, "Component1"));
+        builder.AddRange(CreateRazorComponentTagHelpersCore("First", "Test", "Component2"));
+        builder.AddRange(CreateRazorComponentTagHelpersCore("Second", RootNamespace2, "Component3"));
+        builder.AddRange(CreateRazorComponentTagHelpersCore("Second", RootNamespace2, "Component4"));
+        builder.AddRange(CreateRazorComponentTagHelpersCore("First", "Test", "Component1337"));
+        builder.AddRange(CreateRazorComponentTagHelpersCore("First", "Test.Components", "Directory1"));
+        builder.AddRange(CreateRazorComponentTagHelpersCore("First", "Test.Components", "Directory2"));
+
+        return builder.ToCollection();
+
+        static IEnumerable<TagHelperDescriptor> CreateRazorComponentTagHelpersCore(
+            string assemblyName, string namespaceName, string tagName)
+        {
+            var fullyQualifiedName = $"{namespaceName}.{tagName}";
+            var builder = TagHelperDescriptorBuilder.CreateComponent(fullyQualifiedName, assemblyName);
+            builder.SetTypeName(fullyQualifiedName, namespaceName, tagName);
+            builder.TagMatchingRule(rule => rule.TagName = tagName);
 
-        yield return builder.Build();
+            yield return builder.Build();
 
-        var fullyQualifiedBuilder = TagHelperDescriptorBuilder.CreateComponent(fullyQualifiedName, assemblyName);
-        fullyQualifiedBuilder.SetTypeName(fullyQualifiedName, namespaceName, tagName);
-        fullyQualifiedBuilder.TagMatchingRule(rule => rule.TagName = fullyQualifiedName);
-        fullyQualifiedBuilder.IsFullyQualifiedNameMatch = true;
+            var fullyQualifiedBuilder = TagHelperDescriptorBuilder.CreateComponent(fullyQualifiedName, assemblyName);
+            fullyQualifiedBuilder.SetTypeName(fullyQualifiedName, namespaceName, tagName);
+            fullyQualifiedBuilder.TagMatchingRule(rule => rule.TagName = fullyQualifiedName);
+            fullyQualifiedBuilder.IsFullyQualifiedNameMatch = true;
 
-        yield return fullyQualifiedBuilder.Build();
+            yield return fullyQualifiedBuilder.Build();
+        }
     }
 
     private static Action<SumType<TextEdit, AnnotatedTextEdit>> AssertTextEdit(string fileName, int startLine, int startCharacter, int endLine, int endCharacter)
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Semantic/SemanticTokensTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Semantic/SemanticTokensTest.cs
index f5764b61ca7..a28fa8c6117 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Semantic/SemanticTokensTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/Semantic/SemanticTokensTest.cs
@@ -930,7 +930,7 @@ private async Task AssertSemanticTokensAsync(
     private static DocumentContext CreateDocumentContext(
         string documentText,
         bool isRazorFile,
-        ImmutableArray<TagHelperDescriptor> tagHelpers,
+        TagHelperCollection tagHelpers,
         int version)
     {
         var document = CreateCodeDocument(documentText, isRazorFile, tagHelpers);
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/TagHelperFactsServiceTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/TagHelperFactsServiceTest.cs
index 1c181387342..dfd9cded377 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/TagHelperFactsServiceTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/TagHelperFactsServiceTest.cs
@@ -4,7 +4,6 @@
 #nullable disable
 
 using System;
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.LanguageServer.Completion;
@@ -20,7 +19,7 @@ public class TagHelperFactsServiceTest(ITestOutputHelper testOutput) : TagHelper
     public void StringifyAttributes_DirectiveAttribute()
     {
         // Arrange
-        var codeDocument = CreateComponentDocument($"<TestElement @test='abc' />", DefaultTagHelpers);
+        var codeDocument = CreateComponentDocument($"<TestElement @test='abc' />", [.. DefaultTagHelpers]);
         var root = codeDocument.GetRequiredSyntaxRoot();
         var startTag = (MarkupTagHelperStartTagSyntax)root.FindInnermostNode(3);
 
@@ -41,7 +40,7 @@ public void StringifyAttributes_DirectiveAttribute()
     public void StringifyAttributes_DirectiveAttributeWithParameter()
     {
         // Arrange
-        var codeDocument = CreateComponentDocument($"<TestElement @test:something='abc' />", DefaultTagHelpers);
+        var codeDocument = CreateComponentDocument($"<TestElement @test:something='abc' />", [.. DefaultTagHelpers]);
         var root = codeDocument.GetRequiredSyntaxRoot();
         var startTag = (MarkupTagHelperStartTagSyntax)root.FindInnermostNode(3);
 
@@ -62,7 +61,7 @@ public void StringifyAttributes_DirectiveAttributeWithParameter()
     public void StringifyAttributes_MinimizedDirectiveAttribute()
     {
         // Arrange
-        var codeDocument = CreateComponentDocument($"<TestElement @minimized />", DefaultTagHelpers);
+        var codeDocument = CreateComponentDocument($"<TestElement @minimized />", [.. DefaultTagHelpers]);
         var root = codeDocument.GetRequiredSyntaxRoot();
         var startTag = (MarkupTagHelperStartTagSyntax)root.FindInnermostNode(3);
 
@@ -83,7 +82,7 @@ public void StringifyAttributes_MinimizedDirectiveAttribute()
     public void StringifyAttributes_MinimizedDirectiveAttributeWithParameter()
     {
         // Arrange
-        var codeDocument = CreateComponentDocument($"<TestElement @minimized:something />", DefaultTagHelpers);
+        var codeDocument = CreateComponentDocument($"<TestElement @minimized:something />", [.. DefaultTagHelpers]);
         var root = codeDocument.GetRequiredSyntaxRoot();
         var startTag = (MarkupTagHelperStartTagSyntax)root.FindInnermostNode(3);
 
@@ -238,9 +237,9 @@ public void StringifyAttributes_IgnoresMiscContent()
             });
     }
 
-    private static RazorCodeDocument CreateComponentDocument(string text, ImmutableArray<TagHelperDescriptor> tagHelpers)
+    private static RazorCodeDocument CreateComponentDocument(string text, TagHelperCollection tagHelpers)
     {
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
         var sourceDocument = TestRazorSourceDocument.Create(text);
         var projectEngine = RazorProjectEngine.Create(builder =>
         {
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/LanguageServer/LanguageServerTestBase.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/LanguageServer/LanguageServerTestBase.cs
index 2a8a13f2530..ec292c917e5 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/LanguageServer/LanguageServerTestBase.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/LanguageServer/LanguageServerTestBase.cs
@@ -47,16 +47,20 @@ private protected static RazorRequestContext CreateRazorRequestContext(
         LspServices? lspServices = null)
         => new(documentContext, lspServices ?? LspServices.Empty, "lsp/method", uri: null);
 
-    protected static RazorCodeDocument CreateCodeDocument(string text, ImmutableArray<TagHelperDescriptor> tagHelpers = default, string? filePath = null, string? rootNamespace = null)
+    protected static RazorCodeDocument CreateCodeDocument(
+        string text,
+        TagHelperCollection? tagHelpers = null,
+        string? filePath = null,
+        string? rootNamespace = null)
     {
         filePath ??= "test.cshtml";
 
         var fileKind = FileKinds.GetFileKindFromPath(filePath);
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         if (fileKind == RazorFileKind.Component)
         {
-            tagHelpers = tagHelpers.AddRange(RazorTestResources.BlazorServerAppTagHelpers);
+            tagHelpers = TagHelperCollection.Merge(tagHelpers, [.. RazorTestResources.BlazorServerAppTagHelpers]);
         }
 
         var sourceDocument = TestRazorSourceDocument.Create(text, filePath: filePath, relativePath: filePath);
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestDocumentSnapshot.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestDocumentSnapshot.cs
index 94dbbff64f7..7ad696ba4e4 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestDocumentSnapshot.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestDocumentSnapshot.cs
@@ -42,7 +42,7 @@ public static TestDocumentSnapshot Create(string filePath, string text, ProjectW
     }
 
     public static TestDocumentSnapshot Create(string filePath, RazorCodeDocument codeDocument)
-        => Create(filePath, codeDocument, ProjectWorkspaceState.Create([.. codeDocument.GetTagHelpers() ?? []]));
+        => Create(filePath, codeDocument, ProjectWorkspaceState.Create(codeDocument.GetTagHelpers() ?? []));
 
     public static TestDocumentSnapshot Create(string filePath, RazorCodeDocument codeDocument, ProjectWorkspaceState projectWorkspaceState)
     {
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestProjectSnapshot.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestProjectSnapshot.cs
index d7500551b6c..875cd612fb4 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestProjectSnapshot.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/ProjectSystem/TestProjectSnapshot.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 using System.Threading.Tasks;
@@ -45,7 +44,7 @@ public static TestProjectSnapshot Create(string filePath, ProjectWorkspaceState?
     public string DisplayName => RealSnapshot.DisplayName;
     public LanguageVersion CSharpLanguageVersion => RealSnapshot.CSharpLanguageVersion;
 
-    public ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(CancellationToken cancellationToken)
+    public ValueTask<TagHelperCollection> GetTagHelpersAsync(CancellationToken cancellationToken)
         => RealSnapshot.GetTagHelpersAsync(cancellationToken);
 
     public bool ContainsDocument(string filePath)
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/RazorCodeDocumentFactory.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/RazorCodeDocumentFactory.cs
index 55d7498f907..7d1e3a71bd3 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/RazorCodeDocumentFactory.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/RazorCodeDocumentFactory.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Mvc.Razor.Extensions;
 using Microsoft.AspNetCore.Razor.Language;
 
@@ -15,14 +14,14 @@ internal static class RazorCodeDocumentFactory
     public static string GetFileName(bool isRazorFile)
         => isRazorFile ? RazorFile : CSHtmlFile;
 
-    public static RazorCodeDocument CreateCodeDocument(string text, bool isRazorFile, params ImmutableArray<TagHelperDescriptor> tagHelpers)
+    public static RazorCodeDocument CreateCodeDocument(string text, bool isRazorFile, params TagHelperCollection tagHelpers)
     {
         return CreateCodeDocument(text, GetFileName(isRazorFile), tagHelpers);
     }
 
-    public static RazorCodeDocument CreateCodeDocument(string text, string filePath, params ImmutableArray<TagHelperDescriptor> tagHelpers)
+    public static RazorCodeDocument CreateCodeDocument(string text, string filePath, params TagHelperCollection tagHelpers)
     {
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         var sourceDocument = TestRazorSourceDocument.Create(text, filePath: filePath, relativePath: filePath);
         var projectEngine = RazorProjectEngine.Create(builder =>
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/SimpleTagHelpers.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/SimpleTagHelpers.cs
index 7cf30d8897d..03255601eb5 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/SimpleTagHelpers.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/SimpleTagHelpers.cs
@@ -9,7 +9,7 @@ namespace Microsoft.AspNetCore.Razor.Test.Common;
 
 internal static class SimpleTagHelpers
 {
-    public static ImmutableArray<TagHelperDescriptor> Default { get; }
+    public static TagHelperCollection Default { get; }
 
     static SimpleTagHelpers()
     {
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/TestTagHelperResolver.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/TestTagHelperResolver.cs
index 938aa1e50b8..a53e0ccefdc 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/TestTagHelperResolver.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/TestTagHelperResolver.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
@@ -11,11 +10,11 @@
 
 namespace Microsoft.AspNetCore.Razor.Test.Common;
 
-internal class TestTagHelperResolver(ImmutableArray<TagHelperDescriptor> tagHelpers) : ITagHelperResolver
+internal class TestTagHelperResolver(TagHelperCollection tagHelpers) : ITagHelperResolver
 {
-    public ImmutableArray<TagHelperDescriptor> TagHelpers { get; } = tagHelpers;
+    public TagHelperCollection TagHelpers { get; } = tagHelpers;
 
-    public ValueTask<ImmutableArray<TagHelperDescriptor>> GetTagHelpersAsync(
+    public ValueTask<TagHelperCollection?> GetTagHelpersAsync(
         Project workspaceProject,
         ProjectSnapshot projectSnapshot,
         CancellationToken cancellationToken)
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DefaultRazorCompletionFactsServiceTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DefaultRazorCompletionFactsServiceTest.cs
index 883f42a2227..a15a17460c2 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DefaultRazorCompletionFactsServiceTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DefaultRazorCompletionFactsServiceTest.cs
@@ -18,7 +18,7 @@ public void GetDirectiveCompletionItems_AllProvidersCompletionItems()
         var sourceDocument = RazorSourceDocument.Create("", RazorSourceDocumentProperties.Default);
         var codeDocument = RazorCodeDocument.Create(sourceDocument);
         var syntaxTree = RazorSyntaxTree.Parse(TestRazorSourceDocument.Create());
-        var tagHelperDocumentContext = TagHelperDocumentContext.Create(prefix: null, tagHelpers: []);
+        var tagHelperDocumentContext = TagHelperDocumentContext.Create(tagHelpers: []);
 
         var completionItem1 = RazorCompletionItem.CreateDirective(
             displayText: "displayText1",
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.AttributeNames.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.AttributeNames.cs
index 43879cbf064..c9c19ab7f63 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.AttributeNames.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.AttributeNames.cs
@@ -180,7 +180,7 @@ public void GetCompletionItems_ExistingAttribute_Partial_ReturnsEmptyCollection(
     public void GetAttributeCompletions_NoDescriptorsForTag_ReturnsEmptyCollection()
     {
         // Arrange
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, tagHelpers: []);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers: []);
         var context = GetDefaultDirectivateAttributeCompletionContext("@bin");
 
         // Act
@@ -197,7 +197,7 @@ public void GetAttributeCompletions_NoDirectiveAttributesForTag_ReturnsEmptyColl
         var descriptor = TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly");
         descriptor.BoundAttributeDescriptor(boundAttribute => boundAttribute.Name = "Test");
         descriptor.TagMatchingRule(rule => rule.RequireTagName("*"));
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, [descriptor.Build()]);
+        var documentContext = TagHelperDocumentContext.Create([descriptor.Build()]);
 
         var context = GetDefaultDirectivateAttributeCompletionContext("@bin");
 
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.ParameterNames.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.ParameterNames.cs
index 2fb2929d4a2..2b33d2197a8 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.ParameterNames.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeCompletionItemProviderTest.ParameterNames.cs
@@ -35,7 +35,7 @@ public void GetCompletionItems_OnDirectiveAttributeParameter_ReturnsCompletions(
     public void GetAttributeParameterCompletions_NoDescriptorsForTag_ReturnsEmptyCollection()
     {
         // Arrange
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, tagHelpers: []);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers: []);
         var context = GetDefaultDirectiveAttributeCompletionContext("@bin");
 
         // Act
@@ -52,7 +52,7 @@ public void GetAttributeParameterCompletions_NoDirectiveAttributesForTag_Returns
         var descriptor = TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly");
         descriptor.BoundAttributeDescriptor(boundAttribute => boundAttribute.Name = "Test");
         descriptor.TagMatchingRule(rule => rule.RequireTagName("*"));
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, [descriptor.Build()]);
+        var documentContext = TagHelperDocumentContext.Create([descriptor.Build()]);
 
         var context = GetDefaultDirectiveAttributeCompletionContext("@bin");
 
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeTransitionCompletionItemProviderTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeTransitionCompletionItemProviderTest.cs
index e0359be2311..d2f8a1e50fd 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeTransitionCompletionItemProviderTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveAttributeTransitionCompletionItemProviderTest.cs
@@ -13,8 +13,8 @@ namespace Microsoft.CodeAnalysis.Razor.Completion;
 
 public class DirectiveAttributeTransitionCompletionItemProviderTest(ITestOutputHelper testOutput) : ToolingTestBase(testOutput)
 {
-    private readonly TagHelperDocumentContext _tagHelperDocumentContext = TagHelperDocumentContext.Create(prefix: string.Empty, tagHelpers: []);
-    private readonly DirectiveAttributeTransitionCompletionItemProvider _provider = new DirectiveAttributeTransitionCompletionItemProvider(TestLanguageServerFeatureOptions.Instance);
+    private readonly TagHelperDocumentContext _tagHelperDocumentContext = TagHelperDocumentContext.Create(tagHelpers: []);
+    private readonly DirectiveAttributeTransitionCompletionItemProvider _provider = new(TestLanguageServerFeatureOptions.Instance);
 
     [Fact]
     public void IsValidCompletionPoint_AtPrefixLeadingEdge_ReturnsFalse()
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveCompletionItemProviderTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveCompletionItemProviderTest.cs
index f2d885e2254..95d143fae44 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveCompletionItemProviderTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/DirectiveCompletionItemProviderTest.cs
@@ -425,7 +425,7 @@ private static RazorCompletionContext CreateRazorCompletionContext(TestCode text
         var sourceDocument = RazorSourceDocument.Create("", RazorSourceDocumentProperties.Default);
         var codeDocument = RazorCodeDocument.Create(sourceDocument);
 
-        var tagHelperDocumentContext = TagHelperDocumentContext.Create(prefix: string.Empty, tagHelpers: []);
+        var tagHelperDocumentContext = TagHelperDocumentContext.Create(tagHelpers: []);
         var owner = syntaxTree.Root.FindInnermostNode(absoluteIndex);
         owner = AbstractRazorCompletionFactsService.AdjustSyntaxNodeForWordBoundary(owner, absoluteIndex);
         return new RazorCompletionContext(codeDocument, absoluteIndex, owner, syntaxTree, tagHelperDocumentContext, reason);
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/LanguageServerTagHelperCompletionServiceTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/LanguageServerTagHelperCompletionServiceTest.cs
index 7eb8040c709..f9cb0a48de3 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/LanguageServerTagHelperCompletionServiceTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/LanguageServerTagHelperCompletionServiceTest.cs
@@ -3,7 +3,6 @@
 
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Linq;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common;
 using Xunit;
@@ -17,12 +16,10 @@ public class LanguageServerTagHelperCompletionServiceTest(ITestOutputHelper test
     [WorkItem("https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1452432")]
     public void GetAttributeCompletions_OnlyIndexerNamePrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form"))
+                .TagMatchingRule(tagName: "form")
                 .BoundAttributeDescriptor(attribute => attribute
                     .TypeName("System.Collections.Generic.IDictionary<System.String, System.String>")
                     .PropertyName("RouteValues")
@@ -32,32 +29,29 @@ public void GetAttributeCompletions_OnlyIndexerNamePrefix()
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["asp-route-..."] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["asp-route-..."] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             attributes: [],
             currentTagName: "form");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_BoundDictionaryAttribute_ReturnsPrefixIndexerAndFullSetter()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form"))
+                .TagMatchingRule(tagName: "form")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("asp-all-route-data")
                     .TypeName("System.Collections.Generic.IDictionary<System.String, System.String>")
@@ -68,41 +62,33 @@ public void GetAttributeCompletions_BoundDictionaryAttribute_ReturnsPrefixIndexe
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["asp-all-route-data"] = [documentDescriptors[0].BoundAttributes.Last()],
-            ["asp-route-..."] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["asp-all-route-data"] = [tagHelpers[0].BoundAttributes[^1]],
+            ["asp-route-..."] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             attributes: [],
             currentTagName: "form");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_RequiredBoundDictionaryAttribute_ReturnsPrefixIndexerAndFullSetter()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form")
-                    .RequireAttributeDescriptor(builder =>
-                    {
-                        builder.Name = "asp-route-";
-                        builder.NameComparison = RequiredAttributeNameComparison.PrefixMatch;
-                    }))
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form")
-                    .RequireAttributeDescriptor(builder => builder.Name = "asp-all-route-data"))
+                .TagMatchingRule(tagName: "form", static b => b
+                    .RequiredAttribute(name: "asp-route-", nameComparison: RequiredAttributeNameComparison.PrefixMatch))
+                .TagMatchingRule(tagName: "form", static b => b
+                    .RequiredAttribute(name: "asp-all-route-data"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("asp-all-route-data")
                     .TypeName("System.Collections.Generic.IDictionary<System.String, System.String>")
@@ -113,102 +99,84 @@ public void GetAttributeCompletions_RequiredBoundDictionaryAttribute_ReturnsPref
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["asp-all-route-data"] = [documentDescriptors[0].BoundAttributes.Last()],
-            ["asp-route-..."] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["asp-all-route-data"] = [tagHelpers[0].BoundAttributes[^1]],
+            ["asp-route-..."] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             attributes: [],
             currentTagName: "form");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_DoesNotReturnCompletionsForAlreadySuppliedAttributes()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("visible")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Visible"))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
+                .BoundAttribute<bool>(name: "visible", propertyName: "Visible")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("class")
-                    .TypeName(typeof(string).FullName)
-                    .PropertyName("Class"))
+                .TagMatchingRule(tagName: "*")
+                .BoundAttribute<string>(name: "class", propertyName: "Class")
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["onclick"] = [],
-            ["visible"] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["visible"] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["onclick"],
             attributes: [
                 KeyValuePair.Create("class", "something"),
                 KeyValuePair.Create("repeat", "4")],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_ReturnsCompletionForAlreadySuppliedAttribute_IfCurrentAttributeMatches()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("visible")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Visible"))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
+                .BoundAttribute<bool>(name: "visible", propertyName: "Visible")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("class")
-                    .TypeName(typeof(string).FullName)
-                    .PropertyName("Class"))
+                .TagMatchingRule(tagName: "*")
+                .BoundAttribute<string>(name: "class", propertyName: "Class")
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["onclick"] = [],
-            ["visible"] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["visible"] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["onclick"],
             attributes: [
                 KeyValuePair.Create("class", "something"),
@@ -216,36 +184,27 @@ public void GetAttributeCompletions_ReturnsCompletionForAlreadySuppliedAttribute
                 KeyValuePair.Create("visible", "false")],
             currentTagName: "div",
             currentAttributeName: "visible");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_DoesNotReturnAlreadySuppliedAttribute_IfCurrentAttributeDoesNotMatch()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("visible")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Visible"))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
+                .BoundAttribute<bool>(name: "visible", propertyName: "Visible")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("class")
-                    .TypeName(typeof(string).FullName)
-                    .PropertyName("Class"))
+                .TagMatchingRule(tagName: "*")
+                .BoundAttribute<string>(name: "class", propertyName: "Class")
                 .Build(),
         ];
 
@@ -255,7 +214,7 @@ public void GetAttributeCompletions_DoesNotReturnAlreadySuppliedAttribute_IfCurr
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["onclick"],
             attributes: [
                 KeyValuePair.Create("class", "something"),
@@ -263,30 +222,26 @@ public void GetAttributeCompletions_DoesNotReturnAlreadySuppliedAttribute_IfCurr
                 KeyValuePair.Create("visible", "false")],
             currentTagName: "div",
             currentAttributeName: "repeat");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_PossibleDescriptorsReturnUnboundRequiredAttributesWithExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("*")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("class")))
+                .TagMatchingRule(tagName: "*", static b => b
+                    .RequiredAttribute(name: "class"))
                 .Build(),
         ];
 
@@ -298,136 +253,104 @@ public void GetAttributeCompletions_PossibleDescriptorsReturnUnboundRequiredAttr
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["onclick", "class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_PossibleDescriptorsReturnBoundRequiredAttributesWithExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("repeat")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Repeat"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("visible")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Visible"))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
+                .BoundAttribute<bool>(name: "repeat", propertyName: "Repeat")
+                .BoundAttribute<bool>(name: "visible", propertyName: "Visible")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("*")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("class")))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("class")
-                    .TypeName(typeof(string).FullName)
-                    .PropertyName("Class"))
+                .TagMatchingRule(tagName: "*", static b => b
+                    .RequiredAttribute(name: "class"))
+                .BoundAttribute<string>(name: "class", propertyName: "Class")
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [.. documentDescriptors[1].BoundAttributes],
+            ["class"] = [.. tagHelpers[1].BoundAttributes],
             ["onclick"] = [],
-            ["repeat"] = [documentDescriptors[0].BoundAttributes.First()]
+            ["repeat"] = [tagHelpers[0].BoundAttributes[0]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["onclick"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_AppliedDescriptorsReturnAllBoundAttributesWithExistingCompletionsForSchemaTags()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("repeat")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Repeat"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("visible")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Visible"))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
+                .BoundAttribute<bool>(name: "repeat", propertyName: "Repeat")
+                .BoundAttribute<bool>(name: "visible", propertyName: "Visible")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("*")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("class")))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("class")
-                    .TypeName(typeof(string).FullName)
-                    .PropertyName("Class"))
+                .TagMatchingRule(tagName: "*", static b => b
+                    .RequiredAttribute(name: "class"))
+                .BoundAttribute<string>(name: "class", propertyName: "Class")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("visible")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Visible"))
+                .TagMatchingRule(tagName: "*")
+                .BoundAttribute<bool>(name: "visible", propertyName: "Visible")
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["onclick"] = [],
-            ["class"] = [.. documentDescriptors[1].BoundAttributes],
-            ["repeat"] = [documentDescriptors[0].BoundAttributes.First()],
-            ["visible"] = [documentDescriptors[0].BoundAttributes.Last(), documentDescriptors[2].BoundAttributes.First()]
+            ["class"] = [.. tagHelpers[1].BoundAttributes],
+            ["repeat"] = [tagHelpers[0].BoundAttributes[0]],
+            ["visible"] = [tagHelpers[0].BoundAttributes[^1], tagHelpers[2].BoundAttributes[0]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["class", "onclick"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_AppliedTagOutputHintDescriptorsReturnBoundAttributesWithExistingCompletionsForNonSchemaTags()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CustomTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("custom"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("repeat")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Repeat"))
+                .TagMatchingRule(tagName: "custom")
+                .BoundAttribute<bool>(name: "repeat", propertyName: "Repeat")
                 .TagOutputHint("div")
                 .Build(),
         ];
@@ -435,52 +358,46 @@ public void GetAttributeCompletions_AppliedTagOutputHintDescriptorsReturnBoundAt
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["class"] = [],
-            ["repeat"] = [.. documentDescriptors[0].BoundAttributes]
+            ["repeat"] = [.. tagHelpers[0].BoundAttributes]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["class"],
             currentTagName: "custom");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_AppliedDescriptorsReturnBoundAttributesCompletionsForNonSchemaTags()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CustomTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("custom"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("repeat")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Repeat"))
+                .TagMatchingRule(tagName: "custom")
+                .BoundAttribute<bool>(name: "repeat", propertyName: "Repeat")
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["repeat"] = [.. documentDescriptors[0].BoundAttributes]
+            ["repeat"] = [.. tagHelpers[0].BoundAttributes]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["class"],
             currentTagName: "custom");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
@@ -488,129 +405,116 @@ public void GetAttributeCompletions_AppliedDescriptorsReturnBoundAttributesCompl
     public void GetAttributeCompletions_AppliedDescriptorsReturnBoundAttributesWithExistingCompletionsForSchemaTags()
     {
         // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
-                .BoundAttributeDescriptor(attribute => attribute
-                    .Name("repeat")
-                    .TypeName(typeof(bool).FullName)
-                    .PropertyName("Repeat"))
+                .TagMatchingRule(tagName: "div")
+                .BoundAttribute<bool>(name: "repeat", propertyName: "Repeat")
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["class"] = [],
-            ["repeat"] = [.. documentDescriptors[0].BoundAttributes]
+            ["repeat"] = [.. tagHelpers[0].BoundAttributes]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_NoDescriptorsReturnsExistingCompletions()
     {
-        // Arrange
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [],
+            ["class"] = []
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            descriptors: [],
+            tagHelpers: [],
             existingCompletions: ["class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_NoDescriptorsForUnprefixedTagReturnsExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("special")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute("special"))
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [],
+            ["class"] = []
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["class"],
             currentTagName: "div",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_NoDescriptorsForTagReturnsExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("MyTableTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("table")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("special")))
+                .TagMatchingRule(tagName: "table", static b => b
+                    .RequiredAttribute("special"))
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [],
+            ["class"] = []
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_IgnoresDirectiveAttributes()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BindAttribute", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("input"))
+                .TagMatchingRule(tagName: "input")
                 .BoundAttributeDescriptor(builder =>
                 {
                     builder.Name = "@bind";
@@ -623,536 +527,514 @@ public void GetElementCompletions_IgnoresDirectiveAttributes()
         var expectedCompletions = ElementCompletionResult.Create([]);
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["table"],
             containingTagName: "body",
-            containingParentTagName: null!);
+            containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_FiltersFullyQualifiedElementsIfShortNameExists()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("Test"))
+                .TagMatchingRule(tagName: "Test")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("TestAssembly.Test"))
+                .TagMatchingRule(tagName: "TestAssembly.Test")
                 .IsFullyQualifiedNameMatch(true)
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Test2TagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("Test2Assembly.Test"))
+                .TagMatchingRule(tagName: "Test2Assembly.Test")
                 .IsFullyQualifiedNameMatch(true)
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["Test"] = [documentDescriptors[0]],
-            ["Test2Assembly.Test"] = [documentDescriptors[2]],
+            ["Test"] = [tagHelpers[0]],
+            ["Test2Assembly.Test"] = [tagHelpers[2]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "body",
-            containingParentTagName: null!);
+            containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_TagOutputHintDoesNotFallThroughToSchemaCheck()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("MyTableTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("my-table"))
+                .TagMatchingRule(tagName: "my-table")
                 .TagOutputHint("table")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("MyTrTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("my-tr"))
+                .TagMatchingRule(tagName: "my-tr")
                 .TagOutputHint("tr")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["my-table"] = [documentDescriptors[0]]
+            ["my-table"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["table", "div"],
             containingTagName: "body",
-            containingParentTagName: null!);
+            containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CatchAllsOnlyApplyToCompletionsStartingWithPrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAllTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["th:li"] = [documentDescriptors[1], documentDescriptors[0]],
+            ["th:li"] = [tagHelpers[1], tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["li"],
             containingTagName: "ul",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_TagHelperPrefixIsPrependedToTagHelperCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule(tagName: "superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["th:superli"] = [documentDescriptors[0]],
-            ["th:li"] = [documentDescriptors[1]],
+            ["th:superli"] = [tagHelpers[0]],
+            ["th:li"] = [tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["li"],
             containingTagName: "ul",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_IsCaseSensitive()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("MyliTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("myli"))
+                .TagMatchingRule(tagName: "myli")
                 .SetCaseSensitive()
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("MYLITagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("MYLI"))
+                .TagMatchingRule(tagName: "MYLI")
                 .SetCaseSensitive()
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["myli"] = [documentDescriptors[0]],
-            ["MYLI"] = [documentDescriptors[1]],
+            ["myli"] = [tagHelpers[0]],
+            ["MYLI"] = [tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["li"],
-            containingTagName: "ul",
-            tagHelperPrefix: null!);
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_HTMLSchemaTagName_IsCaseSensitive()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("LITagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("LI"))
+                .TagMatchingRule(tagName: "LI")
                 .SetCaseSensitive()
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .SetCaseSensitive()
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["LI"] = [documentDescriptors[0]],
-            ["li"] = [documentDescriptors[1]],
+            ["LI"] = [tagHelpers[0]],
+            ["li"] = [tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["li"],
-            containingTagName: "ul",
-            tagHelperPrefix: null!);
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CatchAllsApplyToOnlyTagHelperCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule(tagName: "superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
-                .Build(),
+                .TagMatchingRule(tagName: "*")
+                .Build()
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["superli"] = [documentDescriptors[0], documentDescriptors[1]],
+            ["superli"] = [tagHelpers[0], tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["li"],
             containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CatchAllsApplyToNonTagHelperCompletionsIfStartsWithTagHelperPrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule(tagName: "superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["th:superli"] = [documentDescriptors[0], documentDescriptors[1]],
+            ["th:superli"] = [tagHelpers[0], tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["th:li"],
             containingTagName: "ul",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_AllowsMultiTargetingTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldTagHelper1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("b"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("bold"))
+                .TagMatchingRule(tagName: "strong")
+                .TagMatchingRule(tagName: "b")
+                .TagMatchingRule(tagName: "bold")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("BoldTagHelper2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
+                .TagMatchingRule(tagName: "strong")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["strong"] = [documentDescriptors[0], documentDescriptors[1]],
-            ["b"] = [documentDescriptors[0]],
-            ["bold"] = [documentDescriptors[0]],
+            ["strong"] = [tagHelpers[0], tagHelpers[1]],
+            ["b"] = [tagHelpers[0]],
+            ["bold"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["strong", "b", "bold"],
             containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CombinesDescriptorsOnExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["li"] = [documentDescriptors[0], documentDescriptors[1]],
+            ["li"] = [tagHelpers[0], tagHelpers[1]]
         });
 
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions: ["li"], containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_NewCompletionsForSchemaTagsNotInExistingCompletionsAreIgnored()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule(tagName: "superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .TagOutputHint("strong")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["li"] = [documentDescriptors[1]],
-            ["superli"] = [documentDescriptors[0]],
+            ["li"] = [tagHelpers[1]],
+            ["superli"] = [tagHelpers[0]]
         });
 
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions: ["li"], containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_OutputHintIsCrossReferencedWithExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .TagOutputHint("li")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .TagOutputHint("strong")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["div"] = [documentDescriptors[0]],
-            ["li"] = [documentDescriptors[1]],
+            ["div"] = [tagHelpers[0]],
+            ["li"] = [tagHelpers[1]]
         });
 
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions: ["li"], containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_EnsuresDescriptorsHaveSatisfiedParent()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li").RequireParentTag("ol"))
+                .TagMatchingRule(tagName: "li", parentTagName: "ol")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["li"] = [documentDescriptors[0]],
+            ["li"] = [tagHelpers[0]]
         });
 
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions: ["li"], containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_NoContainingParentTag_DoesNotGetCompletionForRuleWithParentTag()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("Tag1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("outer-child-tag"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("child-tag").RequireParentTag("parent-tag"))
+                .TagMatchingRule(tagName: "outer-child-tag")
+                .TagMatchingRule(tagName: "child-tag", parentTagName: "parent-tag")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Tag2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("parent-tag"))
+                .TagMatchingRule(tagName: "parent-tag")
                 .AllowChildTag("child-tag")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["outer-child-tag"] = [documentDescriptors[0]],
-            ["parent-tag"] = [documentDescriptors[1]],
+            ["outer-child-tag"] = [tagHelpers[0]],
+            ["parent-tag"] = [tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
-            containingTagName: null!,
-            containingParentTagName: null!);
+            containingTagName: null,
+            containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_WithContainingParentTag_GetsCompletionForRuleWithParentTag()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("Tag1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("outer-child-tag"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("child-tag").RequireParentTag("parent-tag"))
+                .TagMatchingRule(tagName: "outer-child-tag")
+                .TagMatchingRule(tagName: "child-tag", parentTagName: "parent-tag")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Tag2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("parent-tag"))
+                .TagMatchingRule(tagName: "parent-tag")
                 .AllowChildTag("child-tag")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["child-tag"] = [documentDescriptors[0]],
+            ["child-tag"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "child-tag",
             containingParentTagName: "parent-tag");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_AllowedChildrenAreIgnoredWhenAtRoot()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .AllowChildTag("div")
@@ -1162,27 +1044,25 @@ public void GetElementCompletions_AllowedChildrenAreIgnoredWhenAtRoot()
         var expectedCompletions = ElementCompletionResult.Create([]);
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
-            containingTagName: null!,
-            containingParentTagName: null!);
+            containingTagName: null,
+            containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_DoesNotReturnExistingCompletionsWhenAllowedChildren()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .AllowChildTag("div")
@@ -1193,31 +1073,29 @@ public void GetElementCompletions_DoesNotReturnExistingCompletionsWhenAllowedChi
         {
             ["b"] = [],
             ["bold"] = [],
-            ["div"] = [documentDescriptors[0]]
+            ["div"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["p", "em"],
             containingTagName: "thing",
             containingParentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelpers_NoneTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .Build(),
@@ -1226,31 +1104,29 @@ public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelper
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
             ["b"] = [],
-            ["bold"] = [],
+            ["bold"] = []
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "",
             containingParentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelpers_SomeTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .AllowChildTag("div")
@@ -1261,37 +1137,35 @@ public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelper
         {
             ["b"] = [],
             ["bold"] = [],
-            ["div"] = [documentDescriptors[0]]
+            ["div"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "",
             containingParentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelpers_AllTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParentCatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .AllowChildTag("strong")
                 .AllowChildTag("div")
                 .AllowChildTag("b")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .Build(),
@@ -1299,132 +1173,107 @@ public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelper
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["strong"] = [documentDescriptors[0]],
-            ["b"] = [documentDescriptors[0]],
-            ["bold"] = [documentDescriptors[0]],
-            ["div"] = [documentDescriptors[0], documentDescriptors[1]],
+            ["strong"] = [tagHelpers[0]],
+            ["b"] = [tagHelpers[0]],
+            ["bold"] = [tagHelpers[0]],
+            ["div"] = [tagHelpers[0], tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "",
             containingParentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_MustSatisfyAttributeRules_WithAttributes()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form")
-                .RequireAttributeDescriptor(builder =>
-                    {
-                        builder.Name = "asp-route-";
-                        builder.NameComparison = RequiredAttributeNameComparison.PrefixMatch;
-                    }))
-                .Build(),
+                .TagMatchingRule(tagName: "form", static b => b
+                    .RequiredAttribute(name: "asp-route-", nameComparison: RequiredAttributeNameComparison.PrefixMatch))
+                .Build()
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["form"] = [documentDescriptors[0]]
+            ["form"] = [tagHelpers[0]]
         });
 
-        var attributes = ImmutableArray.Create(
-            KeyValuePair.Create("asp-route-id", "123"));
-
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["form"],
             containingTagName: "",
             containingParentTagName: "div",
-            attributes: attributes);
+            attributes: [KeyValuePair.Create("asp-route-id", "123")]);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_MustSatisfyAttributeRules_NoAttributes()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form")
-                .RequireAttributeDescriptor(builder =>
-                    {
-                        builder.Name = "asp-route-";
-                        builder.NameComparison = RequiredAttributeNameComparison.PrefixMatch;
-                    }))
+                .TagMatchingRule(tagName: "form", static b => b
+                    .RequiredAttribute(name: "asp-route-", nameComparison: RequiredAttributeNameComparison.PrefixMatch))
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create([]);
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: ["form"],
             containingTagName: "",
             containingParentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_MustSatisfyAttributeRules_NoAttributes_AllowedIfNotHtml()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("ComponentTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("component")
-                .RequireAttributeDescriptor(builder =>
-                    {
-                        builder.Name = "type";
-                        builder.NameComparison = RequiredAttributeNameComparison.PrefixMatch;
-                    }))
+                .TagMatchingRule(tagName: "component", static b => b
+                    .RequiredAttribute(name: "type", nameComparison: RequiredAttributeNameComparison.PrefixMatch))
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["component"] = [documentDescriptors[0]],
+            ["component"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "",
             containingParentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
@@ -1455,40 +1304,40 @@ private static void AssertCompletionsAreEquivalent(AttributeCompletionResult exp
     }
 
     private static ElementCompletionContext BuildElementCompletionContext(
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         ImmutableArray<string> existingCompletions,
-        string containingTagName,
-        string containingParentTagName = "body",
+        string? containingTagName,
+        string? containingParentTagName = "body",
         bool containingParentIsTagHelper = false,
-        string tagHelperPrefix = "",
+        string? tagHelperPrefix = null,
         ImmutableArray<KeyValuePair<string, string>> attributes = default)
     {
         attributes = attributes.NullToEmpty();
 
-        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, descriptors);
+        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, tagHelpers);
         var completionContext = new ElementCompletionContext(
             documentContext,
             existingCompletions,
             containingTagName,
             attributes,
-            containingParentTagName: containingParentTagName,
-            containingParentIsTagHelper: containingParentIsTagHelper,
-            inHTMLSchema: (tag) => tag == "strong" || tag == "b" || tag == "bold" || tag == "li" || tag == "div" || tag == "form");
+            containingParentTagName,
+            containingParentIsTagHelper,
+            inHTMLSchema: static tag => tag is "strong" or "b" or "bold" or "li" or "div" or "form");
 
         return completionContext;
     }
 
     private static AttributeCompletionContext BuildAttributeCompletionContext(
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         ImmutableArray<string> existingCompletions,
         string currentTagName,
-        string? currentAttributeName = null!,
+        string? currentAttributeName = null,
         ImmutableArray<KeyValuePair<string, string>> attributes = default,
         string tagHelperPrefix = "")
     {
         attributes = attributes.NullToEmpty();
 
-        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, descriptors);
+        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, tagHelpers);
         var completionContext = new AttributeCompletionContext(
             documentContext,
             existingCompletions,
@@ -1497,7 +1346,7 @@ private static AttributeCompletionContext BuildAttributeCompletionContext(
             attributes,
             currentParentTagName: "body",
             currentParentIsTagHelper: false,
-            inHTMLSchema: (tag) => tag == "strong" || tag == "b" || tag == "bold" || tag == "li" || tag == "div");
+            inHTMLSchema: static tag => tag is "strong" or "b" or "bold" or "li" or "div" or "form");
 
         return completionContext;
     }
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/MarkupTransitionCompletionItemProviderTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/MarkupTransitionCompletionItemProviderTest.cs
index 9a2d954e17b..57467c263a0 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/MarkupTransitionCompletionItemProviderTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/MarkupTransitionCompletionItemProviderTest.cs
@@ -299,7 +299,7 @@ private static RazorCompletionContext CreateRazorCompletionContext(TestCode text
         var sourceDocument = RazorSourceDocument.Create("", RazorSourceDocumentProperties.Default);
         var codeDocument = RazorCodeDocument.Create(sourceDocument);
 
-        var tagHelperDocumentContext = TagHelperDocumentContext.Create(prefix: string.Empty, tagHelpers: []);
+        var tagHelperDocumentContext = TagHelperDocumentContext.Create(tagHelpers: []);
 
         var owner = syntaxTree.Root.FindInnermostNode(absoluteIndex, includeWhitespace: true, walkMarkersBack: true);
         owner = AbstractRazorCompletionFactsService.AdjustSyntaxNodeForWordBoundary(owner, absoluteIndex);
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/RazorCompletionListProviderTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/RazorCompletionListProviderTest.cs
index 97f37a144df..43bc2995f52 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/RazorCompletionListProviderTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Completion/RazorCompletionListProviderTest.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using System.Linq;
 using System.Text.Json;
 using Microsoft.AspNetCore.Razor.Language;
@@ -531,13 +530,13 @@ public void GetCompletionList_ProvidesTagHelperAttributeItems_AttributeQuotesOff
         Assert.Contains(completionList.Items, item => item.InsertText == "testAttribute=$0");
     }
 
-    private static RazorCodeDocument CreateCodeDocument(string text, string documentFilePath, ImmutableArray<TagHelperDescriptor> tagHelpers = default)
+    private static RazorCodeDocument CreateCodeDocument(string text, string documentFilePath, TagHelperCollection? tagHelpers = null)
     {
         var codeDocument = TestRazorCodeDocument.CreateEmpty();
         var sourceDocument = TestRazorSourceDocument.Create(text, filePath: documentFilePath);
         var syntaxTree = RazorSyntaxTree.Parse(sourceDocument);
         codeDocument.SetSyntaxTree(syntaxTree);
-        var tagHelperDocumentContext = TagHelperDocumentContext.Create(prefix: null, tagHelpers.NullToEmpty());
+        var tagHelperDocumentContext = TagHelperDocumentContext.Create(tagHelpers ?? []);
         codeDocument.SetTagHelperContext(tagHelperDocumentContext);
         return codeDocument;
     }
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Extensions/RazorCodeDocumentExtensionsTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Extensions/RazorCodeDocumentExtensionsTest.cs
index 4182c01b517..b1db2fb6de1 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Extensions/RazorCodeDocumentExtensionsTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Extensions/RazorCodeDocumentExtensionsTest.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common;
 using Microsoft.CodeAnalysis.Razor.Protocol;
@@ -350,9 +349,9 @@ public void GetLanguageKind_TagHelperInCSharpRightAssociative()
         Assert.Equal(RazorLanguageKind.Html, languageKind);
     }
 
-    private static RazorCodeDocument CreateCodeDocument(TestCode code, params ImmutableArray<TagHelperDescriptor> tagHelpers)
+    private static RazorCodeDocument CreateCodeDocument(TestCode code, params TagHelperCollection tagHelpers)
     {
-        tagHelpers = tagHelpers.NullToEmpty();
+        tagHelpers ??= [];
 
         var sourceDocument = TestRazorSourceDocument.Create(code.Text);
         var projectEngine = RazorProjectEngine.Create(builder =>
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/ProjectSystem/ProjectStateTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/ProjectSystem/ProjectStateTest.cs
index df7f9b27e09..42f3e053f5d 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/ProjectSystem/ProjectStateTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/ProjectSystem/ProjectStateTest.cs
@@ -603,7 +603,7 @@ public void ProjectState_WithProjectWorkspaceState_Changed_TagHelpersChanged()
 
         // The configuration didn't change, but the tag helpers did
         Assert.Same(state.ProjectEngine, newState.ProjectEngine);
-        Assert.NotEqual<TagHelperDescriptor>(state.TagHelpers, newState.TagHelpers);
+        Assert.NotEqual(state.TagHelpers, newState.TagHelpers);
         Assert.NotSame(state.Documents[SomeProjectFile2.FilePath], newState.Documents[SomeProjectFile2.FilePath]);
         Assert.NotSame(state.Documents[AnotherProjectNestedFile3.FilePath], newState.Documents[AnotherProjectNestedFile3.FilePath]);
     }
@@ -856,11 +856,11 @@ public void ProjectState_RemoveImportDocument_UpdatesRelatedDocuments()
         Assert.Empty(documentPathSet);
     }
 
-    private static void AssertSameTagHelpers(ImmutableArray<TagHelperDescriptor> expected, ImmutableArray<TagHelperDescriptor> actual)
+    private static void AssertSameTagHelpers(TagHelperCollection expected, TagHelperCollection actual)
     {
-        Assert.Equal(expected.Length, actual.Length);
+        Assert.Equal(expected.Count, actual.Count);
 
-        for (var i = 0; i < expected.Length; i++)
+        for (var i = 0; i < expected.Count; i++)
         {
             Assert.Same(expected[i], actual[i]);
         }
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/TagHelperFactsTest.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/TagHelperFactsTest.cs
index 6459e590f32..b120bd78265 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/TagHelperFactsTest.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/TagHelperFactsTest.cs
@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
@@ -18,357 +16,317 @@ public class TagHelperFactsTest(ITestOutputHelper testOutput) : ToolingTestBase(
     [Fact]
     public void GetTagHelperBinding_DoesNotAllowOptOutCharacterPrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var binding = TagHelperFacts.GetTagHelperBinding(documentContext, "!a", ImmutableArray<KeyValuePair<string, string>>.Empty, parentTag: null, parentIsTagHelper: false);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+
+        var binding = TagHelperFacts.GetTagHelperBinding(
+            documentContext,
+            tagName: "!a",
+            attributes: [],
+            parentTag: null,
+            parentIsTagHelper: false);
 
-        // Assert
         Assert.Null(binding);
     }
 
     [Fact]
     public void GetTagHelperBinding_WorksAsExpected()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule =>
-                    rule
-                        .RequireTagName("a")
-                        .RequireAttributeDescriptor(attribute => attribute.Name("asp-for")))
-                .BoundAttributeDescriptor(attribute =>
-                    attribute
-                        .Name("asp-for")
-                        .TypeName(typeof(string).FullName)
-                        .PropertyName("AspFor"))
-                .BoundAttributeDescriptor(attribute =>
-                    attribute
-                        .Name("asp-route")
-                        .TypeName(typeof(IDictionary<string, string>).Namespace + "IDictionary<string, string>")
-                        .PropertyName("AspRoute")
-                        .AsDictionaryAttribute("asp-route-", typeof(string).FullName))
+                .TagMatchingRule(tagName: "a", static b => b
+                    .RequiredAttribute(name: "asp-for"))
+                .BoundAttribute<string>(name: "asp-for", propertyName: "AspFor")
+                .BoundAttribute(name: "asp-route", propertyName: "AspRoute", typeName: typeof(IDictionary<,>).Namespace + "IDictionary<string, string>", static b => b
+                    .AsDictionaryAttribute<string>("asp-route-"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
                 .TagMatchingRuleDescriptor(rule => rule.RequireTagName("input"))
-                .BoundAttributeDescriptor(attribute =>
-                    attribute
-                        .Name("asp-for")
-                        .TypeName(typeof(string).FullName)
-                        .PropertyName("AspFor"))
+                .BoundAttributeDescriptor(attribute => attribute
+                    .Name("asp-for")
+                    .TypeName(typeof(string).FullName)
+                    .PropertyName("AspFor"))
                 .Build(),
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
-        var attributes = ImmutableArray.Create(
-            new KeyValuePair<string, string>("asp-for", "Name"));
-
-        // Act
-        var binding = TagHelperFacts.GetTagHelperBinding(documentContext, "a", attributes, parentTag: "p", parentIsTagHelper: false);
-
-        // Assert
-        var descriptor = Assert.Single(binding.Descriptors);
-        Assert.Equal(documentDescriptors[0], descriptor);
-        var boundRule = Assert.Single(binding.GetBoundRules(descriptor));
-        Assert.Equal(documentDescriptors[0].TagMatchingRules.First(), boundRule);
+
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+
+        var binding = TagHelperFacts.GetTagHelperBinding(
+            documentContext,
+            tagName: "a",
+            attributes: [KeyValuePair.Create("asp-for", "Name")],
+            parentTag: "p",
+            parentIsTagHelper: false);
+
+        Assert.NotNull(binding);
+        var tagHelper = Assert.Single(binding.TagHelpers);
+        Assert.Same(tagHelpers[0], tagHelper);
+        var boundRule = Assert.Single(binding.GetBoundRules(tagHelper));
+        Assert.Same(tagHelpers[0].TagMatchingRules[0], boundRule);
     }
 
     [Fact]
     public void GetBoundTagHelperAttributes_MatchesPrefixedAttributeName()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("a"))
-                .BoundAttributeDescriptor(attribute =>
-                    attribute
-                        .Name("asp-for")
-                        .TypeName(typeof(string).FullName)
-                        .PropertyName("AspFor"))
-                .BoundAttributeDescriptor(attribute =>
-                    attribute
-                        .Name("asp-route")
-                        .TypeName(typeof(IDictionary<string, string>).Namespace + "IDictionary<string, string>")
-                        .PropertyName("AspRoute")
-                        .AsDictionaryAttribute("asp-route-", typeof(string).FullName))
+                .TagMatchingRule(tagName: "a")
+                .BoundAttribute<string>(name: "asp-for", propertyName: "AspFor")
+                .BoundAttribute(name: "asp-route", propertyName: "AspRoute", typeName: typeof(IDictionary<,>).Namespace + "IDictionary<string, string>", static b => b
+                    .AsDictionaryAttribute<string>("asp-route-"))
                 .Build()
         ];
-        var expectedAttributeDescriptors = new[]
-        {
-            documentDescriptors[0].BoundAttributes.Last()
-        };
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
-        var binding = TagHelperFacts.GetTagHelperBinding(documentContext, "a", ImmutableArray<KeyValuePair<string, string>>.Empty, parentTag: null, parentIsTagHelper: false);
 
-        // Act
-        var tagHelperAttributes = TagHelperFacts.GetBoundTagHelperAttributes(documentContext, "asp-route-something", binding);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+        var binding = TagHelperFacts.GetTagHelperBinding(
+            documentContext,
+            tagName: "a",
+            attributes: [],
+            parentTag: null,
+            parentIsTagHelper: false);
+
+        Assert.NotNull(binding);
 
-        // Assert
-        Assert.Equal(expectedAttributeDescriptors, tagHelperAttributes);
+        var result = TagHelperFacts.GetBoundTagHelperAttributes(
+            documentContext,
+            attributeName: "asp-route-something",
+            binding);
+
+        Assert.Same(tagHelpers[0].BoundAttributes[^1], Assert.Single(result));
     }
 
     [Fact]
     public void GetBoundTagHelperAttributes_MatchesAttributeName()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("input"))
-                .BoundAttributeDescriptor(attribute =>
-                    attribute
-                        .Name("asp-for")
-                        .TypeName(typeof(string).FullName)
-                        .PropertyName("AspFor"))
-                .BoundAttributeDescriptor(attribute =>
-                    attribute
-                        .Name("asp-extra")
-                        .TypeName(typeof(string).FullName)
-                        .PropertyName("AspExtra"))
+                .TagMatchingRule(tagName: "input")
+                .BoundAttribute<string>(name: "asp-for", propertyName: "AspFor")
+                .BoundAttribute<string>(name: "asp-extra", propertyName: "AspExtra")
                 .Build()
         ];
-        var expectedAttributeDescriptors = new[]
+
+        var expectedBoundAttributes = new[]
         {
-            documentDescriptors[0].BoundAttributes.First()
+            tagHelpers[0].BoundAttributes.First()
         };
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
-        var binding = TagHelperFacts.GetTagHelperBinding(documentContext, "input", ImmutableArray<KeyValuePair<string, string>>.Empty, parentTag: null, parentIsTagHelper: false);
 
-        // Act
-        var tagHelperAttributes = TagHelperFacts.GetBoundTagHelperAttributes(documentContext, "asp-for", binding);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+
+        var binding = TagHelperFacts.GetTagHelperBinding(
+            documentContext,
+            tagName: "input",
+            attributes: [],
+            parentTag: null,
+            parentIsTagHelper: false);
+
+        Assert.NotNull(binding);
 
-        // Assert
-        Assert.Equal(expectedAttributeDescriptors, tagHelperAttributes);
+        var result = TagHelperFacts.GetBoundTagHelperAttributes(
+            documentContext,
+            attributeName: "asp-for",
+            binding);
+
+        Assert.Equal(expectedBoundAttributes, result);
     }
 
     [Fact]
     public void GetTagHelpersGivenTag_DoesNotAllowOptOutCharacterPrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenTag(documentContext, "!strong", parentTag: null);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+
+        var result = TagHelperFacts.GetTagHelpersGivenTag(
+            documentContext,
+            tagName: "!strong",
+            parentTag: null);
 
-        // Assert
-        Assert.Empty(descriptors);
+        Assert.Empty(result);
     }
 
     [Fact]
     public void GetTagHelpersGivenTag_RequiresTagName()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
+                .TagMatchingRule(tagName: "strong")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenTag(documentContext, "strong", "p");
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
 
-        // Assert
-        Assert.Equal<TagHelperDescriptor>(documentDescriptors, descriptors);
+        var result = TagHelperFacts.GetTagHelpersGivenTag(
+            documentContext,
+            tagName: "strong",
+            parentTag: "p");
+
+        Assert.Equal(tagHelpers, result);
     }
 
     [Fact]
     public void GetTagHelpersGivenTag_RestrictsTagHelpersBasedOnTagName()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(
-                    rule => rule
-                        .RequireTagName("a")
-                        .RequireParentTag("div"))
-                .Build()
-        ];
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
-        [
-            expectedDescriptors[0],
+                .TagMatchingRule(tagName: "a", parentTagName: "div")
+                .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("TestType2", "TestAssembly")
-                .TagMatchingRuleDescriptor(
-                    rule => rule
-                        .RequireTagName("strong")
-                        .RequireParentTag("div"))
+                .TagMatchingRule(tagName: "strong", parentTagName: "div")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenTag(documentContext, "a", "div");
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
 
-        // Assert
-        Assert.Equal<TagHelperDescriptor>(expectedDescriptors, descriptors);
+        var result = TagHelperFacts.GetTagHelpersGivenTag(
+            documentContext,
+            tagName: "a",
+            parentTag: "div");
+
+        Assert.Same(tagHelpers[0], Assert.Single(result));
     }
 
     [Fact]
     public void GetTagHelpersGivenTag_RestrictsTagHelpersBasedOnTagHelperPrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
-                .Build()
-        ];
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
-        [
-            expectedDescriptors[0],
+                .TagMatchingRule(tagName: "strong")
+                .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("TestType2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("thstrong"))
+                .TagMatchingRule(tagName: "thstrong")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create("th", documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenTag(documentContext, "thstrong", "div");
+        var documentContext = TagHelperDocumentContext.Create(prefix: "th", tagHelpers);
 
-        // Assert
-        Assert.Equal<TagHelperDescriptor>(expectedDescriptors, descriptors);
+        var result = TagHelperFacts.GetTagHelpersGivenTag(
+            documentContext,
+            tagName: "thstrong",
+            parentTag: "div");
+
+        Assert.Same(tagHelpers[0], Assert.Single(result));
     }
 
     [Fact]
     public void GetTagHelpersGivenTag_RestrictsTagHelpersBasedOnParent()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(
-                    rule => rule
-                        .RequireTagName("strong")
-                        .RequireParentTag("div"))
-                .Build()
-        ];
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
-        [
-            expectedDescriptors[0],
+                .TagMatchingRule(tagName: "strong", parentTagName: "div")
+                .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("TestType2", "TestAssembly")
-                .TagMatchingRuleDescriptor(
-                    rule => rule
-                        .RequireTagName("strong")
-                        .RequireParentTag("p"))
+                .TagMatchingRule(tagName: "strong", parentTagName: "p")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenTag(documentContext, "strong", "div");
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
 
-        // Assert
-        Assert.Equal<TagHelperDescriptor>(expectedDescriptors, descriptors);
+        var result = TagHelperFacts.GetTagHelpersGivenTag(
+            documentContext,
+            tagName: "strong",
+            parentTag: "div");
+
+        Assert.Same(tagHelpers[0], Assert.Single(result));
     }
 
     [Fact]
     public void GetTagHelpersGivenParent_AllowsRootParentTag()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenParent(documentContext, parentTag: null /* root */);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+
+        var result = TagHelperFacts.GetTagHelpersGivenParent(
+            documentContext,
+            parentTag: null /* root */);
 
-        // Assert
-        Assert.Equal<TagHelperDescriptor>(documentDescriptors, descriptors);
+        Assert.Equal(tagHelpers, result);
     }
 
     [Fact]
     public void GetTagHelpersGivenParent_AllowsRootParentTagForParentRestrictedTagHelperDescriptors()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("p")
-                    .RequireParentTag("body"))
+                .TagMatchingRule(tagName: "p", parentTagName: "body")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenParent(documentContext, parentTag: null /* root */);
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+
+        var result = TagHelperFacts.GetTagHelpersGivenParent(
+            documentContext,
+            parentTag: null /* root */);
 
-        // Assert
-        var descriptor = Assert.Single(descriptors);
-        Assert.Equal(documentDescriptors[0], descriptor);
+        Assert.Same(tagHelpers[0], Assert.Single(result));
     }
 
     [Fact]
     public void GetTagHelpersGivenParent_AllowsUnspecifiedParentTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenParent(documentContext, "p");
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
 
-        // Assert
-        Assert.Equal<TagHelperDescriptor>(documentDescriptors, descriptors);
+        var result = TagHelperFacts.GetTagHelpersGivenParent(
+            documentContext,
+            parentTag: "p");
+
+        Assert.Equal(tagHelpers, result);
     }
 
     [Fact]
     public void GetTagHelpersGivenParent_RestrictsTagHelpersBasedOnParent()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> expectedDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestType", "TestAssembly")
-                .TagMatchingRuleDescriptor(
-                    rule => rule
-                        .RequireTagName("p")
-                        .RequireParentTag("div"))
-                .Build()
-        ];
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
-        [
-            expectedDescriptors[0],
+                .TagMatchingRule(tagName: "p", parentTagName: "div")
+                .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("TestType2", "TestAssembly")
-                .TagMatchingRuleDescriptor(
-                    rule => rule
-                        .RequireTagName("strong")
-                        .RequireParentTag("p"))
+                .TagMatchingRule(tagName: "strong", parentTagName: "p")
                 .Build()
         ];
-        var documentContext = TagHelperDocumentContext.Create(string.Empty, documentDescriptors);
 
-        // Act
-        var descriptors = TagHelperFacts.GetTagHelpersGivenParent(documentContext, "div");
+        var documentContext = TagHelperDocumentContext.Create(tagHelpers);
+
+        var result = TagHelperFacts.GetTagHelpersGivenParent(
+            documentContext,
+            parentTag: "div");
 
-        // Assert
-        Assert.Equal<TagHelperDescriptor>(expectedDescriptors, descriptors);
+        Assert.Same(tagHelpers[0], Assert.Single(result));
     }
 }
diff --git a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Tooltip/ProjectAvailabilityTests.cs b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Tooltip/ProjectAvailabilityTests.cs
index d5aa947c690..760d2c9f28f 100644
--- a/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Tooltip/ProjectAvailabilityTests.cs
+++ b/src/Razor/test/Microsoft.CodeAnalysis.Razor.Workspaces.Test/Tooltip/ProjectAvailabilityTests.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Immutable;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common;
@@ -32,8 +31,7 @@ public async Task GetProjectAvailabilityText_OneProject_ReturnsNull()
         builder.TagMatchingRule(rule => rule.TagName = "Test");
         var tagHelperTypeName = "TestNamespace.TestTagHelper";
         builder.TypeName = tagHelperTypeName;
-        var tagHelpers = ImmutableArray.Create(builder.Build());
-        var projectWorkspaceState = ProjectWorkspaceState.Create(tagHelpers);
+        var projectWorkspaceState = ProjectWorkspaceState.Create([builder.Build()]);
 
         var hostProject = new HostProject(
             "C:/path/to/project.csproj",
@@ -70,8 +68,7 @@ public async Task GetProjectAvailabilityText_AvailableInAllProjects_ReturnsNull(
         builder.TagMatchingRule(rule => rule.TagName = "Test");
         var tagHelperTypeName = "TestNamespace.TestTagHelper";
         builder.TypeName = tagHelperTypeName;
-        var tagHelpers = ImmutableArray.Create(builder.Build());
-        var projectWorkspaceState = ProjectWorkspaceState.Create(tagHelpers);
+        var projectWorkspaceState = ProjectWorkspaceState.Create([builder.Build()]);
 
         var hostProject1 = new HostProject(
             "C:/path/to/project.csproj",
@@ -119,8 +116,7 @@ public async Task GetProjectAvailabilityText_NotAvailableInAllProjects_ReturnsTe
         builder.TagMatchingRule(rule => rule.TagName = "Test");
         var tagHelperTypeName = "TestNamespace.TestTagHelper";
         builder.TypeName = tagHelperTypeName;
-        var tagHelpers = ImmutableArray.Create(builder.Build());
-        var projectWorkspaceState = ProjectWorkspaceState.Create(tagHelpers);
+        var projectWorkspaceState = ProjectWorkspaceState.Create([builder.Build()]);
 
         var hostProject1 = new HostProject(
             "C:/path/to/project.csproj",
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.TestResolver.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.TestResolver.cs
index 7a985e2aa79..d319b8b9cb4 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.TestResolver.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.TestResolver.cs
@@ -24,15 +24,31 @@ private class TestResolver(
         ITelemetryReporter telemetryReporter)
         : OutOfProcTagHelperResolver(remoteServiceInvoker, loggerFactory, telemetryReporter)
     {
-        public Func<ProjectSnapshot, ValueTask<ImmutableArray<TagHelperDescriptor>>>? OnResolveOutOfProcess { get; init; }
+        public Func<ProjectSnapshot, TagHelperCollection>? OnResolveOutOfProcess { get; init; }
 
-        public Func<ProjectSnapshot, ValueTask<ImmutableArray<TagHelperDescriptor>>>? OnResolveInProcess { get; init; }
+        public Func<ProjectSnapshot, TagHelperCollection>? OnResolveInProcess { get; init; }
 
-        protected override ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTagHelpersOutOfProcessAsync(Project project, ProjectSnapshot projectSnapshot, CancellationToken cancellationToken)
-            => OnResolveOutOfProcess?.Invoke(projectSnapshot) ?? default;
+        protected override ValueTask<TagHelperCollection?> ResolveTagHelpersOutOfProcessAsync(Project project, ProjectSnapshot projectSnapshot, CancellationToken cancellationToken)
+        {
+            var handler = OnResolveOutOfProcess;
+            if (handler is not null)
+            {
+                return new(handler.Invoke(projectSnapshot));
+            }
 
-        protected override ValueTask<ImmutableArray<TagHelperDescriptor>> ResolveTagHelpersInProcessAsync(Project project, ProjectSnapshot projectSnapshot, CancellationToken cancellationToken)
-            => OnResolveInProcess?.Invoke(projectSnapshot) ?? default;
+            return default;
+        }
+
+        protected override ValueTask<TagHelperCollection> ResolveTagHelpersInProcessAsync(Project project, ProjectSnapshot projectSnapshot, CancellationToken cancellationToken)
+        {
+            var handler = OnResolveInProcess;
+            if (handler is not null)
+            {
+                return new(handler.Invoke(projectSnapshot));
+            }
+
+            return default;
+        }
 
         public ImmutableArray<Checksum> PublicProduceChecksumsFromDelta(ProjectId projectId, int lastResultId, TagHelperDeltaResult deltaResult)
             => ProduceChecksumsFromDelta(projectId, lastResultId, deltaResult);
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.cs
index 150e9af6804..2ace1071c4f 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/OutOfProcTagHelperResolverTest.cs
@@ -93,7 +93,7 @@ await _projectManager.UpdateAsync(updater =>
 
                 Assert.Same(projectSnapshot, p);
 
-                return new([]);
+                return [];
             },
         };
 
@@ -101,6 +101,7 @@ await _projectManager.UpdateAsync(updater =>
 
         // Assert
         Assert.True(calledOutOfProcess);
+        Assert.NotNull(result);
         Assert.Empty(result);
     }
 
@@ -125,14 +126,14 @@ await _projectManager.UpdateAsync(updater =>
                 calledOutOfProcess = true;
 
                 Assert.Same(projectSnapshot, p);
-                return new([]);
+                return [];
             },
             OnResolveInProcess = (p) =>
             {
                 calledInProcess = true;
 
                 Assert.Same(projectSnapshot, p);
-                return new([]);
+                return [];
             },
         };
 
@@ -141,6 +142,7 @@ await _projectManager.UpdateAsync(updater =>
         // Assert
         Assert.True(calledOutOfProcess);
         Assert.False(calledInProcess);
+        Assert.NotNull(result);
         Assert.Empty(result);
     }
 
@@ -172,7 +174,7 @@ await _projectManager.UpdateAsync(updater =>
                 calledInProcess = true;
 
                 Assert.Same(projectSnapshot, p);
-                return new([]);
+                return [];
             },
         };
 
@@ -181,6 +183,7 @@ await _projectManager.UpdateAsync(updater =>
         // Assert
         Assert.True(calledOutOfProcess);
         Assert.True(calledInProcess);
+        Assert.NotNull(result);
         Assert.Empty(result);
     }
 
@@ -205,7 +208,7 @@ await _projectManager.UpdateAsync(updater =>
 
                 Assert.Same(projectSnapshot, p);
 
-                return new([]);
+                return [];
             },
         };
 
@@ -213,6 +216,7 @@ await _projectManager.UpdateAsync(updater =>
 
         // Assert
         Assert.True(calledInProcess);
+        Assert.NotNull(result);
         Assert.Empty(result);
     }
 
@@ -238,7 +242,7 @@ await _projectManager.UpdateAsync(updater =>
                 calledInProcess = true;
                 Assert.Same(projectSnapshot, p);
 
-                return new([]);
+                return [];
             },
             OnResolveOutOfProcess = (p) =>
             {
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/ProjectStateUpdaterTest.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/ProjectStateUpdaterTest.cs
index e9cc8f0e517..e3c399afb17 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/ProjectStateUpdaterTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Discovery/ProjectStateUpdaterTest.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
@@ -36,7 +35,7 @@ protected override Task InitializeAsync()
         var solution = Workspace.CurrentSolution.AddProject(projectInfo);
         Workspace.TryApplyChanges(solution);
 
-        ImmutableArray<TagHelperDescriptor> tagHelpers = [
+        TagHelperCollection tagHelpers = [
             TagHelperDescriptorBuilder.CreateTagHelper("ResolvableTagHelper", "TestAssembly").Build()];
         _projectWorkspaceState = ProjectWorkspaceState.Create(tagHelpers);
         _tagHelperResolver = new TestTagHelperResolver(tagHelpers);
@@ -164,6 +163,6 @@ await _projectManager.UpdateAsync(updater =>
         // Assert
         var newProjectSnapshot = _projectManager.GetRequiredProject(s_hostProject.Key);
 
-        Assert.Equal<TagHelperDescriptor>(_tagHelperResolver.TagHelpers, await newProjectSnapshot.GetTagHelpersAsync(DisposalToken));
+        Assert.Equal(_tagHelperResolver.TagHelpers, await newProjectSnapshot.GetTagHelpersAsync(DisposalToken));
     }
 }
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Guest/ProjectSnapshotSynchronizationServiceTest.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Guest/ProjectSnapshotSynchronizationServiceTest.cs
index 2191fd2128a..db1537fc0f3 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Guest/ProjectSnapshotSynchronizationServiceTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Guest/ProjectSnapshotSynchronizationServiceTest.cs
@@ -66,11 +66,7 @@ public async Task InitializeAsync_RetrievesHostProjectManagerStateAndInitializes
         Assert.Same(RazorConfiguration.Default, project.Configuration);
 
         var tagHelpers = await project.GetTagHelpersAsync(DisposalToken);
-        Assert.Equal(_projectWorkspaceStateWithTagHelpers.TagHelpers.Length, tagHelpers.Length);
-        for (var i = 0; i < _projectWorkspaceStateWithTagHelpers.TagHelpers.Length; i++)
-        {
-            Assert.Same(_projectWorkspaceStateWithTagHelpers.TagHelpers[i], tagHelpers[i]);
-        }
+        Assert.SameItems(_projectWorkspaceStateWithTagHelpers.TagHelpers, tagHelpers);
     }
 
     [UIFact]
@@ -101,11 +97,7 @@ public async Task UpdateGuestProjectManager_ProjectAdded()
         Assert.Same(RazorConfiguration.Default, project.Configuration);
 
         var tagHelpers = await project.GetTagHelpersAsync(DisposalToken);
-        Assert.Equal(_projectWorkspaceStateWithTagHelpers.TagHelpers.Length, tagHelpers.Length);
-        for (var i = 0; i < _projectWorkspaceStateWithTagHelpers.TagHelpers.Length; i++)
-        {
-            Assert.Same(_projectWorkspaceStateWithTagHelpers.TagHelpers[i], tagHelpers[i]);
-        }
+        Assert.SameItems(_projectWorkspaceStateWithTagHelpers.TagHelpers, tagHelpers);
     }
 
     [UIFact]
@@ -228,10 +220,6 @@ await _projectManager.UpdateAsync(updater =>
         Assert.Same(RazorConfiguration.Default, project.Configuration);
 
         var tagHelpers = await project.GetTagHelpersAsync(DisposalToken);
-        Assert.Equal(_projectWorkspaceStateWithTagHelpers.TagHelpers.Length, tagHelpers.Length);
-        for (var i = 0; i < _projectWorkspaceStateWithTagHelpers.TagHelpers.Length; i++)
-        {
-            Assert.Same(_projectWorkspaceStateWithTagHelpers.TagHelpers[i], tagHelpers[i]);
-        }
+        Assert.SameItems(_projectWorkspaceStateWithTagHelpers.TagHelpers, tagHelpers);
     }
 }
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Host/ProjectSnapshotManagerProxyTest.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Host/ProjectSnapshotManagerProxyTest.cs
index 97dc44e30b3..f4df85a3959 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Host/ProjectSnapshotManagerProxyTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/Host/ProjectSnapshotManagerProxyTest.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Immutable;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.Language;
@@ -244,10 +243,10 @@ await projectManager.UpdateAsync(updater =>
 
     private static Action<ProjectSnapshotHandleProxy> AssertProjectSnapshotHandle(
         string expectedFilePath,
-        ImmutableArray<TagHelperDescriptor> expectedTagHelpers)
+        TagHelperCollection expectedTagHelpers)
         => handle =>
         {
             Assert.Equal(expectedFilePath, handle.FilePath.ToString());
-            Assert.Equal<TagHelperDescriptor>(expectedTagHelpers, handle.ProjectWorkspaceState.TagHelpers);
+            Assert.Equal(expectedTagHelpers, handle.ProjectWorkspaceState.TagHelpers);
         };
 }
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/SerializationTest.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/SerializationTest.cs
index ce58c110c25..d621aa9d9b6 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/SerializationTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/LiveShare/SerializationTest.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
@@ -19,9 +18,9 @@ public class SerializationTest(ITestOutputHelper testOutput) : ToolingTestBase(t
     public void ProjectSnapshotHandleProxy_RoundTripsProperly()
     {
         // Arrange
-        var tagHelpers = ImmutableArray.Create(
+        TagHelperCollection tagHelpers = [
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly").Build(),
-            TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper2", "TestAssembly2").Build());
+            TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper2", "TestAssembly2").Build()];
 
         var projectWorkspaceState = ProjectWorkspaceState.Create(tagHelpers);
         var expectedConfiguration = RazorConfiguration.Default;
diff --git a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/ProjectSnapshotManagerTest.cs b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/ProjectSnapshotManagerTest.cs
index eb78d7b7185..4b8422cddb8 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/ProjectSnapshotManagerTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/ProjectSystem/ProjectSnapshotManagerTest.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
-using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -51,12 +50,10 @@ public class ProjectSnapshotManagerTest : VisualStudioWorkspaceTestBase
     public ProjectSnapshotManagerTest(ITestOutputHelper testOutput)
         : base(testOutput)
     {
-        var someTagHelpers = ImmutableArray.Create(
-            TagHelperDescriptorBuilder.CreateTagHelper("Test1", "TestAssembly").Build());
-
         _projectManager = CreateProjectSnapshotManager();
 
-        _projectWorkspaceStateWithTagHelpers = ProjectWorkspaceState.Create(someTagHelpers);
+        _projectWorkspaceStateWithTagHelpers = ProjectWorkspaceState.Create([
+            TagHelperDescriptorBuilder.CreateTagHelper("Test1", "TestAssembly").Build()]);
 
         _sourceText = SourceText.From("Hello world");
     }
@@ -282,11 +279,7 @@ await _projectManager.UpdateAsync(updater =>
             .GetRequiredProject(s_hostProject.Key)
             .GetTagHelpersAsync(DisposalToken);
 
-        Assert.Equal(originalTagHelpers.Length, newTagHelpers.Length);
-        for (var i = 0; i < originalTagHelpers.Length; i++)
-        {
-            Assert.Same(originalTagHelpers[i], newTagHelpers[i]);
-        }
+        Assert.SameItems(originalTagHelpers, newTagHelpers);
     }
 
     [UIFact]
@@ -412,11 +405,7 @@ await _projectManager.UpdateAsync(updater =>
             .GetRequiredProject(s_hostProject.Key)
             .GetTagHelpersAsync(DisposalToken);
 
-        Assert.Equal(originalTagHelpers.Length, newTagHelpers.Length);
-        for (var i = 0; i < originalTagHelpers.Length; i++)
-        {
-            Assert.Same(originalTagHelpers[i], newTagHelpers[i]);
-        }
+        Assert.SameItems(originalTagHelpers, newTagHelpers);
     }
 
     [UIFact]
diff --git a/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/LegacyTagHelperCompletionServiceTest.cs b/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/LegacyTagHelperCompletionServiceTest.cs
index 0bc031aac44..623a43df8fe 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/LegacyTagHelperCompletionServiceTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/LegacyTagHelperCompletionServiceTest.cs
@@ -3,7 +3,6 @@
 
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Linq;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Test.Common;
 using Microsoft.CodeAnalysis.Razor.Completion;
@@ -18,12 +17,10 @@ public class LegacyTagHelperCompletionServiceTest(ITestOutputHelper testOutput)
     [WorkItem("https://devdiv.visualstudio.com/DevDiv/_workitems/edit/1452432")]
     public void GetAttributeCompletions_OnlyIndexerNamePrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form"))
+                .TagMatchingRule(tagName: "form")
                 .BoundAttributeDescriptor(attribute => attribute
                     .TypeName("System.Collections.Generic.IDictionary<System.String, System.String>")
                     .PropertyName("RouteValues")
@@ -33,32 +30,29 @@ public void GetAttributeCompletions_OnlyIndexerNamePrefix()
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["asp-route-..."] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["asp-route-..."] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             attributes: [],
             currentTagName: "form");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_BoundDictionaryAttribute_ReturnsPrefixIndexerAndFullSetter()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form"))
+                .TagMatchingRule(tagName: "form")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("asp-all-route-data")
                     .TypeName("System.Collections.Generic.IDictionary<System.String, System.String>")
@@ -69,41 +63,33 @@ public void GetAttributeCompletions_BoundDictionaryAttribute_ReturnsPrefixIndexe
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["asp-all-route-data"] = [documentDescriptors[0].BoundAttributes.Last()],
-            ["asp-route-..."] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["asp-all-route-data"] = [tagHelpers[0].BoundAttributes[^1]],
+            ["asp-route-..."] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             attributes: [],
             currentTagName: "form");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_RequiredBoundDictionaryAttribute_ReturnsPrefixIndexerAndFullSetter()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("FormTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form")
-                    .RequireAttributeDescriptor(builder =>
-                    {
-                        builder.Name = "asp-route-";
-                        builder.NameComparison = RequiredAttributeNameComparison.PrefixMatch;
-                    }))
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("form")
-                    .RequireAttributeDescriptor(builder => builder.Name = "asp-all-route-data"))
+                .TagMatchingRule(tagName: "form", static b => b
+                    .RequiredAttribute(name: "asp-route-", nameComparison: RequiredAttributeNameComparison.PrefixMatch))
+                .TagMatchingRule(tagName: "form", static b => b
+                    .RequiredAttribute(name: "asp-all-route-data"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("asp-all-route-data")
                     .TypeName("System.Collections.Generic.IDictionary<System.String, System.String>")
@@ -114,41 +100,38 @@ public void GetAttributeCompletions_RequiredBoundDictionaryAttribute_ReturnsPref
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["asp-all-route-data"] = [documentDescriptors[0].BoundAttributes.Last()],
-            ["asp-route-..."] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["asp-all-route-data"] = [tagHelpers[0].BoundAttributes[^1]],
+            ["asp-route-..."] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             attributes: [],
             currentTagName: "form");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_DoesNotReturnCompletionsForAlreadySuppliedAttributes()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("visible")
                     .TypeName(typeof(bool).FullName)
                     .PropertyName("Visible"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("class")
                     .TypeName(typeof(string).FullName)
@@ -159,43 +142,39 @@ public void GetAttributeCompletions_DoesNotReturnCompletionsForAlreadySuppliedAt
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["onclick"] = [],
-            ["visible"] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["visible"] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
-        var existingCompletions = new[] { "onclick" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["onclick"],
             attributes: [
                 KeyValuePair.Create("class", "something"),
                 KeyValuePair.Create("repeat", "4")],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_ReturnsCompletionForAlreadySuppliedAttribute_IfCurrentAttributeMatches()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("visible")
                     .TypeName(typeof(bool).FullName)
                     .PropertyName("Visible"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule("*")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("class")
                     .TypeName(typeof(string).FullName)
@@ -206,45 +185,41 @@ public void GetAttributeCompletions_ReturnsCompletionForAlreadySuppliedAttribute
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["onclick"] = [],
-            ["visible"] = [documentDescriptors[0].BoundAttributes.Last()]
+            ["visible"] = [tagHelpers[0].BoundAttributes[^1]]
         });
 
-        var existingCompletions = new[] { "onclick" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["onclick"],
             attributes: [
                 KeyValuePair.Create("class", "something"),
                 KeyValuePair.Create("repeat", "4"),
                 KeyValuePair.Create("visible", "false")],
             currentTagName: "div",
             currentAttributeName: "visible");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_DoesNotReturnAlreadySuppliedAttribute_IfCurrentAttributeDoesNotMatch()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("visible")
                     .TypeName(typeof(bool).FullName)
                     .PropertyName("Visible"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule("*")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("class")
                     .TypeName(typeof(string).FullName)
@@ -257,40 +232,35 @@ public void GetAttributeCompletions_DoesNotReturnAlreadySuppliedAttribute_IfCurr
             ["onclick"] = []
         });
 
-        var existingCompletions = new[] { "onclick" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["onclick"],
             attributes: [
                 KeyValuePair.Create("class", "something"),
                 KeyValuePair.Create("repeat", "4"),
                 KeyValuePair.Create("visible", "false")],
             currentTagName: "div",
             currentAttributeName: "repeat");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_PossibleDescriptorsReturnUnboundRequiredAttributesWithExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("*")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("class")))
+                .TagMatchingRule(tagName: "*", static b => b
+                    .RequiredAttribute(name: "class"))
                 .Build(),
         ];
 
@@ -301,30 +271,26 @@ public void GetAttributeCompletions_PossibleDescriptorsReturnUnboundRequiredAttr
             ["repeat"] = []
         });
 
-        var existingCompletions = new[] { "onclick", "class" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["onclick", "class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_PossibleDescriptorsReturnBoundRequiredAttributesWithExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("repeat")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "repeat"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("repeat")
                     .TypeName(typeof(bool).FullName)
@@ -335,9 +301,8 @@ public void GetAttributeCompletions_PossibleDescriptorsReturnBoundRequiredAttrib
                     .PropertyName("Visible"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("*")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("class")))
+                .TagMatchingRule(tagName: "*", static b => b
+                    .RequiredAttribute(name: "class"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("class")
                     .TypeName(typeof(string).FullName)
@@ -347,33 +312,30 @@ public void GetAttributeCompletions_PossibleDescriptorsReturnBoundRequiredAttrib
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [.. documentDescriptors[1].BoundAttributes],
+            ["class"] = [.. tagHelpers[1].BoundAttributes],
             ["onclick"] = [],
-            ["repeat"] = [documentDescriptors[0].BoundAttributes.First()]
+            ["repeat"] = [tagHelpers[0].BoundAttributes[0]]
         });
 
-        var existingCompletions = new[] { "onclick" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["onclick"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_AppliedDescriptorsReturnAllBoundAttributesWithExistingCompletionsForSchemaTags()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule("div")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("repeat")
                     .TypeName(typeof(bool).FullName)
@@ -384,52 +346,49 @@ public void GetAttributeCompletions_AppliedDescriptorsReturnAllBoundAttributesWi
                     .PropertyName("Visible"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("*")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("class")))
+                .TagMatchingRule(tagName: "*", static b => b
+                    .RequiredAttribute(name: "class"))
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("class")
                     .TypeName(typeof(string).FullName)
                     .PropertyName("Class"))
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("StyleTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("visible")
                     .TypeName(typeof(bool).FullName)
                     .PropertyName("Visible"))
                 .Build(),
         ];
+
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["onclick"] = [],
-            ["class"] = [.. documentDescriptors[1].BoundAttributes],
-            ["repeat"] = [documentDescriptors[0].BoundAttributes.First()],
-            ["visible"] = [documentDescriptors[0].BoundAttributes.Last(), documentDescriptors[2].BoundAttributes.First()]
+            ["class"] = [.. tagHelpers[1].BoundAttributes],
+            ["repeat"] = [tagHelpers[0].BoundAttributes[0]],
+            ["visible"] = [tagHelpers[0].BoundAttributes[^1], tagHelpers[2].BoundAttributes[0]]
         });
 
-        var existingCompletions = new[] { "class", "onclick" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["class", "onclick"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_AppliedTagOutputHintDescriptorsReturnBoundAttributesWithExistingCompletionsForNonSchemaTags()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CustomTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("custom"))
+                .TagMatchingRule(tagName: "custom")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("repeat")
                     .TypeName(typeof(bool).FullName)
@@ -441,31 +400,28 @@ public void GetAttributeCompletions_AppliedTagOutputHintDescriptorsReturnBoundAt
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["class"] = [],
-            ["repeat"] = [.. documentDescriptors[0].BoundAttributes]
+            ["repeat"] = [.. tagHelpers[0].BoundAttributes]
         });
 
-        var existingCompletions = new[] { "class" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["class"],
             currentTagName: "custom");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_AppliedDescriptorsReturnBoundAttributesCompletionsForNonSchemaTags()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CustomTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("custom"))
+                .TagMatchingRule(tagName: "custom")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("repeat")
                     .TypeName(typeof(bool).FullName)
@@ -475,31 +431,28 @@ public void GetAttributeCompletions_AppliedDescriptorsReturnBoundAttributesCompl
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["repeat"] = [.. documentDescriptors[0].BoundAttributes]
+            ["repeat"] = [.. tagHelpers[0].BoundAttributes]
         });
 
-        var existingCompletions = new[] { "class" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["class"],
             currentTagName: "custom");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_AppliedDescriptorsReturnBoundAttributesWithExistingCompletionsForSchemaTags()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .BoundAttributeDescriptor(attribute => attribute
                     .Name("repeat")
                     .TypeName(typeof(bool).FullName)
@@ -510,119 +463,105 @@ public void GetAttributeCompletions_AppliedDescriptorsReturnBoundAttributesWithE
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
             ["class"] = [],
-            ["repeat"] = [.. documentDescriptors[0].BoundAttributes]
+            ["repeat"] = [.. tagHelpers[0].BoundAttributes]
         });
 
-        var existingCompletions = new[] { "class" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_NoDescriptorsReturnsExistingCompletions()
     {
-        // Arrange
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [],
+            ["class"] = []
         });
 
-        var existingCompletions = new[] { "class" };
         var completionContext = BuildAttributeCompletionContext(
-            descriptors: [],
-            existingCompletions,
+            tagHelpers: [],
+            existingCompletions: ["class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_NoDescriptorsForUnprefixedTagReturnsExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("div")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("special")))
+                .TagMatchingRule(tagName: "div", static b => b
+                    .RequiredAttribute(name: "special"))
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [],
+            ["class"] = []
         });
 
-        var existingCompletions = new[] { "class" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["class"],
             currentTagName: "div",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetAttributeCompletions_NoDescriptorsForTagReturnsExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("MyTableTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule
-                    .RequireTagName("table")
-                    .RequireAttributeDescriptor(attribute => attribute.Name("special")))
+                .TagMatchingRule(tagName: "table", static b => b
+                    .RequiredAttribute(name: "special"))
                 .Build(),
         ];
 
         var expectedCompletions = AttributeCompletionResult.Create(new()
         {
-            ["class"] = [],
+            ["class"] = []
         });
 
-        var existingCompletions = new[] { "class" };
         var completionContext = BuildAttributeCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["class"],
             currentTagName: "div");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetAttributeCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_IgnoresDirectiveAttributes()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BindAttribute", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("input"))
+                .TagMatchingRule(tagName: "input")
                 .BoundAttributeDescriptor(builder =>
                 {
                     builder.Name = "@bind";
@@ -634,559 +573,524 @@ public void GetElementCompletions_IgnoresDirectiveAttributes()
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["table"] = [],
+            ["table"] = []
         });
 
-        var existingCompletions = new[] { "table" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["table"],
             containingTagName: "body",
             containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_FiltersFullyQualifiedElementsIfShortNameExists()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("Test"))
+                .TagMatchingRule("Test")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("TestTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("TestAssembly.Test"))
+                .TagMatchingRule("TestAssembly.Test")
                 .IsFullyQualifiedNameMatch(true)
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Test2TagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("Test2Assembly.Test"))
+                .TagMatchingRule("Test2Assembly.Test")
                 .IsFullyQualifiedNameMatch(true)
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["Test"] = [documentDescriptors[0]],
-            ["Test2Assembly.Test"] = [documentDescriptors[2]],
+            ["Test"] = [tagHelpers[0]],
+            ["Test2Assembly.Test"] = [tagHelpers[2]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "body",
             containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_TagOutputHintDoesNotFallThroughToSchemaCheck()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("MyTableTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("my-table"))
+                .TagMatchingRule("my-table")
                 .TagOutputHint("table")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("MyTrTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("my-tr"))
+                .TagMatchingRule("my-tr")
                 .TagOutputHint("tr")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["my-table"] = [documentDescriptors[0]],
-            ["table"] = [],
+            ["my-table"] = [tagHelpers[0]],
+            ["table"] = []
         });
 
-        var existingCompletions = new[] { "table" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["table"],
             containingTagName: "body",
             containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CatchAllsOnlyApplyToCompletionsStartingWithPrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAllTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule("*")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule("li")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["th:li"] = [documentDescriptors[1], documentDescriptors[0]],
-            ["li"] = [],
+            ["th:li"] = [tagHelpers[1], tagHelpers[0]],
+            ["li"] = []
         });
 
-        var existingCompletions = new[] { "li" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["li"],
             containingTagName: "ul",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_TagHelperPrefixIsPrependedToTagHelperCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule("superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule("li")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["th:superli"] = [documentDescriptors[0]],
-            ["th:li"] = [documentDescriptors[1]],
-            ["li"] = [],
+            ["th:superli"] = [tagHelpers[0]],
+            ["th:li"] = [tagHelpers[1]],
+            ["li"] = []
         });
 
-        var existingCompletions = new[] { "li" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["li"],
             containingTagName: "ul",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_IsCaseSensitive()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("MyliTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("myli"))
+                .TagMatchingRule("myli")
                 .SetCaseSensitive()
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("MYLITagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("MYLI"))
+                .TagMatchingRule("MYLI")
                 .SetCaseSensitive()
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["myli"] = [documentDescriptors[0]],
-            ["MYLI"] = [documentDescriptors[1]],
-            ["li"] = [],
+            ["myli"] = [tagHelpers[0]],
+            ["MYLI"] = [tagHelpers[1]],
+            ["li"] = []
         });
 
-        var existingCompletions = new[] { "li" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
-            containingTagName: "ul",
-            tagHelperPrefix: null);
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_HTMLSchemaTagName_IsCaseSensitive()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("LITagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("LI"))
+                .TagMatchingRule("LI")
                 .SetCaseSensitive()
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule("li")
                 .SetCaseSensitive()
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["LI"] = [documentDescriptors[0]],
-            ["li"] = [documentDescriptors[1]],
+            ["LI"] = [tagHelpers[0]],
+            ["li"] = [tagHelpers[1]]
         });
 
-        var existingCompletions = new[] { "li" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
-            containingTagName: "ul",
-            tagHelperPrefix: null);
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CatchAllsApplyToOnlyTagHelperCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule(tagName: "superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["superli"] = [documentDescriptors[0], documentDescriptors[1]],
-            ["li"] = [],
+            ["superli"] = [tagHelpers[0], tagHelpers[1]],
+            ["li"] = []
         });
 
-        var existingCompletions = new[] { "li" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["li"],
             containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CatchAllsApplyToNonTagHelperCompletionsIfStartsWithTagHelperPrefix()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule(tagName: "superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule(tagName: "*")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["th:superli"] = [documentDescriptors[0], documentDescriptors[1]],
-            ["th:li"] = [documentDescriptors[1]],
+            ["th:superli"] = [tagHelpers[0], tagHelpers[1]],
+            ["th:li"] = [tagHelpers[1]]
         });
 
-        var existingCompletions = new[] { "th:li" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["th:li"],
             containingTagName: "ul",
             tagHelperPrefix: "th:");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_AllowsMultiTargetingTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldTagHelper1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("b"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("bold"))
+                .TagMatchingRule(tagName: "strong")
+                .TagMatchingRule(tagName: "b")
+                .TagMatchingRule(tagName: "bold")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("BoldTagHelper2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("strong"))
+                .TagMatchingRule(tagName: "strong")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["strong"] = [documentDescriptors[0], documentDescriptors[1]],
-            ["b"] = [documentDescriptors[0]],
-            ["bold"] = [documentDescriptors[0]],
+            ["strong"] = [tagHelpers[0], tagHelpers[1]],
+            ["b"] = [tagHelpers[0]],
+            ["bold"] = [tagHelpers[0]]
         });
 
-        var existingCompletions = new[] { "strong", "b", "bold" };
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
-            existingCompletions,
+            tagHelpers,
+            existingCompletions: ["strong", "b", "bold"],
             containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CombinesDescriptorsOnExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["li"] = [documentDescriptors[0], documentDescriptors[1]],
+            ["li"] = [tagHelpers[0], tagHelpers[1]]
         });
 
-        var existingCompletions = new[] { "li" };
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions, containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_NewCompletionsForSchemaTagsNotInExistingCompletionsAreIgnored()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("SuperLiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("superli"))
+                .TagMatchingRule(tagName: "superli")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .TagOutputHint("strong")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["li"] = [documentDescriptors[1]],
-            ["superli"] = [documentDescriptors[0]],
+            ["li"] = [tagHelpers[1]],
+            ["superli"] = [tagHelpers[0]]
         });
 
-        var existingCompletions = new[] { "li" };
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions, containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_OutputHintIsCrossReferencedWithExistingCompletions()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("DivTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule(tagName: "div")
                 .TagOutputHint("li")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .TagOutputHint("strong")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["div"] = [documentDescriptors[0]],
-            ["li"] = [documentDescriptors[1]],
+            ["div"] = [tagHelpers[0]],
+            ["li"] = [tagHelpers[1]]
         });
 
-        var existingCompletions = new[] { "li" };
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions, containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_EnsuresDescriptorsHaveSatisfiedParent()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li"))
+                .TagMatchingRule(tagName: "li")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("LiTagHelper2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("li").RequireParentTag("ol"))
+                .TagMatchingRule(tagName: "li", parentTagName: "ol")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["li"] = [documentDescriptors[0]],
+            ["li"] = [tagHelpers[0]]
         });
 
-        var existingCompletions = new[] { "li" };
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions, containingTagName: "ul");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["li"],
+            containingTagName: "ul");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_NoContainingParentTag_DoesNotGetCompletionForRuleWithParentTag()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("Tag1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("outer-child-tag"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("child-tag").RequireParentTag("parent-tag"))
+                .TagMatchingRule(tagName: "outer-child-tag")
+                .TagMatchingRule(tagName: "child-tag", parentTagName: "parent-tag")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Tag2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("parent-tag"))
+                .TagMatchingRule(tagName: "parent-tag")
                 .AllowChildTag("child-tag")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["outer-child-tag"] = [documentDescriptors[0]],
-            ["parent-tag"] = [documentDescriptors[1]],
+            ["outer-child-tag"] = [tagHelpers[0]],
+            ["parent-tag"] = [tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: null,
             containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_WithContainingParentTag_GetsCompletionForRuleWithParentTag()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("Tag1", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("outer-child-tag"))
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("child-tag").RequireParentTag("parent-tag"))
+                .TagMatchingRule(tagName: "outer-child-tag")
+                .TagMatchingRule(tagName: "child-tag", parentTagName: "parent-tag")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("Tag2", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("parent-tag"))
+                .TagMatchingRule(tagName: "parent-tag")
                 .AllowChildTag("child-tag")
                 .Build(),
         ];
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["child-tag"] = [documentDescriptors[0]],
+            ["child-tag"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "parent-tag",
             containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_AllowedChildrenAreIgnoredWhenAtRoot()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("CatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule("*")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .AllowChildTag("div")
@@ -1196,27 +1100,25 @@ public void GetElementCompletions_AllowedChildrenAreIgnoredWhenAtRoot()
         var expectedCompletions = ElementCompletionResult.Create([]);
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: null,
             containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_DoesNotReturnExistingCompletionsWhenAllowedChildren()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule("div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .AllowChildTag("div")
@@ -1227,28 +1129,29 @@ public void GetElementCompletions_DoesNotReturnExistingCompletionsWhenAllowedChi
         {
             ["b"] = [],
             ["bold"] = [],
-            ["div"] = [documentDescriptors[0]]
+            ["div"] = [tagHelpers[0]]
         });
 
-        var existingCompletions = new[] { "p", "em" };
-        var completionContext = BuildElementCompletionContext(documentDescriptors, existingCompletions, containingTagName: "div", containingParentTagName: "thing");
+        var completionContext = BuildElementCompletionContext(
+            tagHelpers,
+            existingCompletions: ["p", "em"],
+            containingTagName: "div",
+            containingParentTagName: "thing");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelpers_NoneTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule("div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .Build(),
@@ -1257,31 +1160,29 @@ public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelper
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
             ["b"] = [],
-            ["bold"] = [],
+            ["bold"] = []
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "div",
             containingParentTagName: "");
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelpers_SomeTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule("div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .AllowChildTag("div")
@@ -1292,37 +1193,35 @@ public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelper
         {
             ["b"] = [],
             ["bold"] = [],
-            ["div"] = [documentDescriptors[0]]
+            ["div"] = [tagHelpers[0]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "div",
-            containingParentTagName: "");
+            containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
     [Fact]
     public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelpers_AllTagHelpers()
     {
-        // Arrange
-        ImmutableArray<TagHelperDescriptor> documentDescriptors =
+        TagHelperCollection tagHelpers =
         [
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParentCatchAll", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("*"))
+                .TagMatchingRule("*")
                 .AllowChildTag("strong")
                 .AllowChildTag("div")
                 .AllowChildTag("b")
                 .Build(),
             TagHelperDescriptorBuilder.CreateTagHelper("BoldParent", "TestAssembly")
-                .TagMatchingRuleDescriptor(rule => rule.RequireTagName("div"))
+                .TagMatchingRule("div")
                 .AllowChildTag("b")
                 .AllowChildTag("bold")
                 .Build(),
@@ -1330,23 +1229,22 @@ public void GetElementCompletions_CapturesAllAllowedChildTagsFromParentTagHelper
 
         var expectedCompletions = ElementCompletionResult.Create(new()
         {
-            ["strong"] = [documentDescriptors[0]],
-            ["b"] = [documentDescriptors[0]],
-            ["bold"] = [documentDescriptors[0]],
-            ["div"] = [documentDescriptors[0], documentDescriptors[1]],
+            ["strong"] = [tagHelpers[0]],
+            ["b"] = [tagHelpers[0]],
+            ["bold"] = [tagHelpers[0]],
+            ["div"] = [tagHelpers[0], tagHelpers[1]]
         });
 
         var completionContext = BuildElementCompletionContext(
-            documentDescriptors,
+            tagHelpers,
             existingCompletions: [],
             containingTagName: "div",
-            containingParentTagName: "");
+            containingParentTagName: null);
+
         var service = CreateTagHelperCompletionFactsService();
 
-        // Act
         var completions = service.GetElementCompletions(completionContext);
 
-        // Assert
         AssertCompletionsAreEquivalent(expectedCompletions, completions);
     }
 
@@ -1377,37 +1275,37 @@ private static void AssertCompletionsAreEquivalent(AttributeCompletionResult exp
     }
 
     private static ElementCompletionContext BuildElementCompletionContext(
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         IEnumerable<string> existingCompletions,
         string? containingTagName,
         string? containingParentTagName = "body",
         bool containingParentIsTagHelper = false,
-        string? tagHelperPrefix = "")
+        string? tagHelperPrefix = null)
     {
-        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, descriptors);
+        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, tagHelpers);
         var completionContext = new ElementCompletionContext(
             documentContext,
             existingCompletions,
             containingTagName,
             attributes: [],
-            containingParentTagName: containingParentTagName,
-            containingParentIsTagHelper: containingParentIsTagHelper,
-            inHTMLSchema: (tag) => tag == "strong" || tag == "b" || tag == "bold" || tag == "li" || tag == "div");
+            containingParentTagName,
+            containingParentIsTagHelper,
+            inHTMLSchema: static tag => tag is "strong" or "b" or "bold" or "li" or "div");
 
         return completionContext;
     }
 
     private static AttributeCompletionContext BuildAttributeCompletionContext(
-        ImmutableArray<TagHelperDescriptor> descriptors,
+        TagHelperCollection tagHelpers,
         IEnumerable<string> existingCompletions,
         string currentTagName,
         string? currentAttributeName = null,
         ImmutableArray<KeyValuePair<string, string>> attributes = default,
-        string tagHelperPrefix = "")
+        string? tagHelperPrefix = null)
     {
         attributes = attributes.NullToEmpty();
 
-        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, descriptors);
+        var documentContext = TagHelperDocumentContext.Create(tagHelperPrefix, tagHelpers);
         var completionContext = new AttributeCompletionContext(
             documentContext,
             existingCompletions,
@@ -1416,7 +1314,7 @@ private static AttributeCompletionContext BuildAttributeCompletionContext(
             attributes,
             currentParentTagName: "body",
             currentParentIsTagHelper: false,
-            inHTMLSchema: (tag) => tag == "strong" || tag == "b" || tag == "bold" || tag == "li" || tag == "div");
+            inHTMLSchema: static tag => tag is "strong" or "b" or "bold" or "li" or "div");
 
         return completionContext;
     }
diff --git a/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/RazorDirectiveCompletionSourceTest.cs b/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/RazorDirectiveCompletionSourceTest.cs
index 8d24812aa5e..d60b646c253 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/RazorDirectiveCompletionSourceTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Completion/RazorDirectiveCompletionSourceTest.cs
@@ -211,7 +211,7 @@ private static IVisualStudioRazorParser CreateParser(string text, params Directi
         var syntaxTree = RazorSyntaxTree.Parse(source, codeDocument.ParserOptions);
         codeDocument.SetSyntaxTree(syntaxTree);
 
-        codeDocument.SetTagHelperContext(TagHelperDocumentContext.Create(prefix: null, tagHelpers: []));
+        codeDocument.SetTagHelperContext(TagHelperDocumentContext.Create(tagHelpers: []));
 
         var parserMock = new StrictMock<IVisualStudioRazorParser>();
         parserMock
diff --git a/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Parsing/RazorSyntaxTreePartialParserTest.cs b/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Parsing/RazorSyntaxTreePartialParserTest.cs
index cd58b74d648..7cd634cdf2f 100644
--- a/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Parsing/RazorSyntaxTreePartialParserTest.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.LegacyEditor.Razor.Test/Parsing/RazorSyntaxTreePartialParserTest.cs
@@ -3,7 +3,6 @@
 
 #nullable disable
 
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Mvc.Razor.Extensions;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Language.Legacy;
@@ -43,11 +42,8 @@ public void TagHelperTagBodiesRejectPartialChanges(object objectEdit)
         var builder = TagHelperDescriptorBuilder.CreateTagHelper("PTagHelper", "TestAssembly");
         builder.TypeName = "PTagHelper";
         builder.TagMatchingRule(rule => rule.TagName = "p");
-        var descriptors = new[]
-        {
-            builder.Build()
-        };
-        var projectEngine = CreateProjectEngine(tagHelpers: descriptors);
+        TagHelperCollection tagHelpers = [builder.Build()];
+        var projectEngine = CreateProjectEngine(tagHelpers);
         var projectItem = new TestRazorProjectItem("Index.cshtml")
         {
             Content = edit.OldSnapshot.GetText()
@@ -116,8 +112,8 @@ public void TagHelperAttributesAreLocatedAndAcceptChangesCorrectly(object editOb
             attribute.TypeName = typeof(string).FullName;
             attribute.PropertyName = "StringAttribute";
         });
-        var descriptors = new[] { builder.Build() };
-        var projectEngine = CreateProjectEngine(tagHelpers: descriptors);
+        TagHelperCollection tagHelpers = [builder.Build()];
+        var projectEngine = CreateProjectEngine(tagHelpers);
         var sourceDocument = new TestRazorProjectItem("Index.cshtml")
         {
             Content = edit.OldSnapshot.GetText()
@@ -390,8 +386,7 @@ private static TestEdit CreateInsertionChange(string initialText, int insertionL
         return new TestEdit(sourceChange, oldSnapshot, changedSnapshot);
     }
 
-    private static RazorProjectEngine CreateProjectEngine(
-        IEnumerable<TagHelperDescriptor> tagHelpers = null)
+    private static RazorProjectEngine CreateProjectEngine(TagHelperCollection tagHelpers = null)
     {
         var fileSystem = new TestRazorProjectFileSystem();
         var projectEngine = RazorProjectEngine.Create(RazorConfiguration.Default, fileSystem, builder =>
@@ -402,7 +397,7 @@ private static RazorProjectEngine CreateProjectEngine(
 
             if (tagHelpers != null)
             {
-                builder.AddTagHelpers(tagHelpers);
+                builder.SetTagHelpers(tagHelpers);
             }
 
             builder.ConfigureParserOptions(VisualStudioRazorParser.ConfigureParserOptions);
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectReaders_ProjectSystem.cs b/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectReaders_ProjectSystem.cs
index 840a796aa4c..c226bb85a2f 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectReaders_ProjectSystem.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectReaders_ProjectSystem.cs
@@ -36,13 +36,15 @@ public static DocumentSnapshotHandle ReadDocumentSnapshotHandleFromProperties(Js
 
     public static ProjectWorkspaceState ReadProjectWorkspaceStateFromProperties(JsonDataReader reader)
     {
-        var tagHelpers = reader.ReadImmutableArrayOrEmpty(nameof(ProjectWorkspaceState.TagHelpers),
+        var array = reader.ReadImmutableArrayOrEmpty(nameof(ProjectWorkspaceState.TagHelpers),
             static r => ReadTagHelper(r
 #if JSONSERIALIZATION_ENABLETAGHELPERCACHE
                 , useCache: true
 #endif
             ));
 
+        var tagHelpers = TagHelperCollection.Create(array);
+
         return ProjectWorkspaceState.Create(tagHelpers);
     }
 
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectWriters_ProjectSystem.cs b/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectWriters_ProjectSystem.cs
index c70979cf9f3..532374ff235 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectWriters_ProjectSystem.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/ObjectWriters_ProjectSystem.cs
@@ -35,7 +35,7 @@ public static void Write(JsonDataWriter writer, ProjectWorkspaceState? value)
 
     public static void WriteProperties(JsonDataWriter writer, ProjectWorkspaceState value)
     {
-        writer.WriteArrayIfNotDefaultOrEmpty(nameof(value.TagHelpers), value.TagHelpers, Write);
+        writer.WriteArrayIfNotNullOrEmpty(nameof(value.TagHelpers), value.TagHelpers, Write);
     }
 
     public static void Write(JsonDataWriter writer, RazorProjectInfo value)
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/SerializationFormat.cs b/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/SerializationFormat.cs
index 807fc8c3729..9dee6f06b45 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/SerializationFormat.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Serialization.Json/SerializationFormat.cs
@@ -9,5 +9,5 @@ internal static class SerializationFormat
     // or any of the types that compose it changes. This includes: RazorConfiguration,
     // ProjectWorkspaceState, TagHelperDescriptor, and DocumentSnapshotHandle.
     // NOTE: If this version is changed, a coordinated insertion is required between Roslyn and Razor for the C# extension.
-    public const int Version = 15;
+    public const int Version = 16;
 }
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/Intermediate/IntermediateNodeAssert.cs b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/Intermediate/IntermediateNodeAssert.cs
index 174bf215658..a1675327ef4 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/Intermediate/IntermediateNodeAssert.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/Intermediate/IntermediateNodeAssert.cs
@@ -307,7 +307,12 @@ internal static void PreallocatedTagHelperPropertyValue(
         }
     }
 
-    internal static void TagHelper(string tagName, TagMode tagMode, IEnumerable<TagHelperDescriptor> tagHelpers, IntermediateNode node, params Action<IntermediateNode>[] childValidators)
+    internal static void TagHelper(
+        string tagName,
+        TagMode tagMode,
+        TagHelperCollection tagHelpers,
+        IntermediateNode node,
+        params Action<IntermediateNode>[] childValidators)
     {
         var tagHelperNode = Assert.IsType<TagHelperIntermediateNode>(node);
 
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineBuilderExtensions.cs b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineBuilderExtensions.cs
index 09d0fc9b180..10761e45eb8 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineBuilderExtensions.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineBuilderExtensions.cs
@@ -30,12 +30,7 @@ public static RazorProjectEngineBuilder AddDefaultImports(this RazorProjectEngin
         return builder;
     }
 
-    public static RazorProjectEngineBuilder AddTagHelpers(this RazorProjectEngineBuilder builder, params TagHelperDescriptor[] tagHelpers)
-    {
-        return AddTagHelpers(builder, (IEnumerable<TagHelperDescriptor>)tagHelpers);
-    }
-
-    public static RazorProjectEngineBuilder AddTagHelpers(this RazorProjectEngineBuilder builder, IEnumerable<TagHelperDescriptor> tagHelpers)
+    public static RazorProjectEngineBuilder SetTagHelpers(this RazorProjectEngineBuilder builder, params TagHelperCollection tagHelpers)
     {
         var feature = (TestTagHelperFeature)builder.Features.OfType<ITagHelperFeature>().FirstOrDefault();
         if (feature == null)
@@ -44,7 +39,7 @@ public static RazorProjectEngineBuilder AddTagHelpers(this RazorProjectEngineBui
             builder.Features.Add(feature);
         }
 
-        feature.TagHelpers.AddRange(tagHelpers);
+        feature.SetTagHelpers(tagHelpers);
         return builder;
     }
 
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineExtensions.cs b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineExtensions.cs
index 3113d6ab4ed..02e624b04ac 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineExtensions.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/RazorProjectEngineExtensions.cs
@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Xunit;
@@ -32,33 +31,33 @@ public static RazorCodeDocument CreateEmptyCodeDocument(
 
     public static RazorCodeDocument CreateEmptyCodeDocument(
         this RazorProjectEngine projectEngine,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyCodeDocumentCore(tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateEmptyCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorFileKind fileKind,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyCodeDocumentCore(fileKind, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateEmptyCodeDocument(
         this RazorProjectEngine projectEngine,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyCodeDocumentCore(importSources: importSources, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateEmptyCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyCodeDocumentCore(fileKind, importSources, tagHelpers);
 
     private static RazorCodeDocument CreateEmptyCodeDocumentCore(
         this RazorProjectEngine projectEngine,
         RazorFileKind? fileKind = null,
         ImmutableArray<RazorSourceDocument> importSources = default,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers = null)
+        TagHelperCollection? tagHelpers = null)
         => projectEngine.CreateCodeDocumentCore(string.Empty, fileKind, importSources, tagHelpers);
 
     public static RazorCodeDocument CreateEmptyDesignTimeCodeDocument(this RazorProjectEngine projectEngine)
@@ -80,33 +79,33 @@ public static RazorCodeDocument CreateEmptyDesignTimeCodeDocument(
 
     public static RazorCodeDocument CreateEmptyDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyDesignTimeCodeDocumentCore(tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateEmptyDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorFileKind fileKind,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyDesignTimeCodeDocumentCore(fileKind, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateEmptyDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyDesignTimeCodeDocumentCore(importSources: importSources, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateEmptyDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateEmptyDesignTimeCodeDocumentCore(fileKind, importSources, tagHelpers);
 
     private static RazorCodeDocument CreateEmptyDesignTimeCodeDocumentCore(
         this RazorProjectEngine projectEngine,
         RazorFileKind? fileKind = null,
         ImmutableArray<RazorSourceDocument> importSources = default,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers = null)
+        TagHelperCollection? tagHelpers = null)
         => projectEngine.CreateDesignTimeCodeDocumentCore(string.Empty, fileKind, importSources, tagHelpers);
 
     public static RazorCodeDocument CreateCodeDocument(this RazorProjectEngine projectEngine, string content)
@@ -131,21 +130,21 @@ public static RazorCodeDocument CreateCodeDocument(
     public static RazorCodeDocument CreateCodeDocument(
         this RazorProjectEngine projectEngine,
         string content,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(content, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateCodeDocument(
         this RazorProjectEngine projectEngine,
         string content,
         RazorFileKind fileKind,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(content, fileKind, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateCodeDocument(
         this RazorProjectEngine projectEngine,
         string content,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(content, importSources: importSources, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateCodeDocument(
@@ -153,7 +152,7 @@ public static RazorCodeDocument CreateCodeDocument(
         string content,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateCodeDocumentCore(content, fileKind, importSources, tagHelpers);
 
     private static RazorCodeDocument CreateCodeDocumentCore(
@@ -161,7 +160,7 @@ private static RazorCodeDocument CreateCodeDocumentCore(
         string content,
         RazorFileKind? fileKind = null,
         ImmutableArray<RazorSourceDocument> importSources = default,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers = null)
+        TagHelperCollection? tagHelpers = null)
     {
         var source = TestRazorSourceDocument.Create(content);
 
@@ -174,7 +173,7 @@ public static RazorCodeDocument CreateDesignTimeCodeDocument(this RazorProjectEn
     public static RazorCodeDocument CreateDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         string content,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers)
+        TagHelperCollection? tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(content, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateDesignTimeCodeDocument(this RazorProjectEngine projectEngine, string content, RazorFileKind fileKind)
@@ -184,7 +183,7 @@ public static RazorCodeDocument CreateDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         string content,
         RazorFileKind fileKind,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers)
+        TagHelperCollection? tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(content, fileKind, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateDesignTimeCodeDocument(
@@ -197,7 +196,7 @@ public static RazorCodeDocument CreateDesignTimeCodeDocument(
         this RazorProjectEngine projectEngine,
         string content,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(content, importSources: importSources, tagHelpers: tagHelpers);
 
     public static RazorCodeDocument CreateDesignTimeCodeDocument(
@@ -212,7 +211,7 @@ public static RazorCodeDocument CreateDesignTimeCodeDocument(
         string content,
         RazorFileKind fileKind,
         ImmutableArray<RazorSourceDocument> importSources,
-        IReadOnlyList<TagHelperDescriptor> tagHelpers)
+        TagHelperCollection tagHelpers)
         => projectEngine.CreateDesignTimeCodeDocumentCore(content, fileKind, importSources, tagHelpers);
 
     private static RazorCodeDocument CreateDesignTimeCodeDocumentCore(
@@ -220,7 +219,7 @@ private static RazorCodeDocument CreateDesignTimeCodeDocumentCore(
         string content,
         RazorFileKind? fileKind = null,
         ImmutableArray<RazorSourceDocument> importSources = default,
-        IReadOnlyList<TagHelperDescriptor>? tagHelpers = null)
+        TagHelperCollection? tagHelpers = null)
     {
         var source = TestRazorSourceDocument.Create(content);
 
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/TestTagHelperFeature.cs b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/TestTagHelperFeature.cs
index 1c025f604ae..f573bdc1774 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/TestTagHelperFeature.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/TestTagHelperFeature.cs
@@ -1,25 +1,19 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Collections.Generic;
 using System.Threading;
 
 namespace Microsoft.AspNetCore.Razor.Language;
 
 public class TestTagHelperFeature : RazorEngineFeatureBase, ITagHelperFeature
 {
-    public TestTagHelperFeature()
-    {
-        TagHelpers = [];
-    }
+    private TagHelperCollection? _tagHelpers;
 
-    public TestTagHelperFeature(IEnumerable<TagHelperDescriptor> tagHelpers)
+    public void SetTagHelpers(TagHelperCollection tagHelpers)
     {
-        TagHelpers = [.. tagHelpers];
+        _tagHelpers = tagHelpers;
     }
 
-    public List<TagHelperDescriptor> TagHelpers { get; }
-
-    public IReadOnlyList<TagHelperDescriptor> GetDescriptors(CancellationToken cancellationToken = default)
-        => [.. TagHelpers];
+    public TagHelperCollection GetTagHelpers(CancellationToken cancellationToken = default)
+        => _tagHelpers ?? [];
 }
diff --git a/src/Shared/files/Tooling/Telerik/Kendo.Mvc.Examples.project.razor.json b/src/Shared/files/Tooling/Telerik/Kendo.Mvc.Examples.project.razor.json
index 73dd551958b..c6f0bf87ffb 100644
--- a/src/Shared/files/Tooling/Telerik/Kendo.Mvc.Examples.project.razor.json
+++ b/src/Shared/files/Tooling/Telerik/Kendo.Mvc.Examples.project.razor.json
@@ -1,5 +1,5 @@
 {
-  "__Version": 15,
+  "__Version": 16,
   "ProjectKey": "C:/Users/admin/location/Kendo.Mvc.Examples/obj/Debug/net7.0/",
   "FilePath": "C:\\Users\\admin\\location\\Kendo.Mvc.Examples\\Kendo.Mvc.Examples.csproj",
   "Configuration": {
diff --git a/src/Shared/files/Tooling/project.razor.json b/src/Shared/files/Tooling/project.razor.json
index 40d69a1bb61..a89e35c9d80 100644
--- a/src/Shared/files/Tooling/project.razor.json
+++ b/src/Shared/files/Tooling/project.razor.json
@@ -1,5 +1,5 @@
 {
-  "__Version": 15,
+  "__Version": 16,
   "ProjectKey": "C:/Users/admin/location/blazorserver/obj/Debug/net7.0/",
   "FilePath": "C:\\Users\\admin\\location\\blazorserver\\blazorserver.csproj",
   "Configuration": {