From e4c4dac3fe6166300096363730bb1d81f0707825 Mon Sep 17 00:00:00 2001
From: Todd Grunke <toddgrun@microsoft.com>
Date: Fri, 17 Oct 2025 09:58:31 -0700
Subject: [PATCH 1/5] Use shared instances of NodeWriter classes

Several of the NodeWriter classes don't have state and can have a shared instance used among callers. These allocations aren't huge in the profiles, but the RazorEditingTests.ScrollingAndTypingInCohosting speedometer test shows about 3 MB of allocating these in the CodeAnalysis process.
---
 .../DesignTimeNodeWriterTest.cs               | 38 +++++-----
 .../LiteralRuntimeNodeWriterTest.cs           |  4 +-
 .../CodeGeneration/RuntimeNodeWriterTest.cs   | 71 ++++++++-----------
 ...elperHtmlAttributeRuntimeNodeWriterTest.cs |  6 +-
 .../Extensions/TemplateTargetExtensionTest.cs | 12 ++--
 .../CodeGeneration/DefaultCodeTarget.cs       |  4 +-
 .../CodeGeneration/DesignTimeNodeWriter.cs    |  4 +-
 .../CodeGeneration/IntermediateNodeWriter.cs  |  2 -
 .../LiteralRuntimeNodeWriter.cs               |  6 +-
 .../CodeGeneration/RuntimeNodeWriter.cs       | 19 ++---
 ...TagHelperHtmlAttributeRuntimeNodeWriter.cs |  6 +-
 .../DefaultTagHelperTargetExtension.cs        |  8 +--
 .../TestCodeRenderingContext.cs               |  4 +-
 13 files changed, 87 insertions(+), 97 deletions(-)

diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs
index f7e23f0b44e..43d9bced96f 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs
@@ -21,7 +21,7 @@ protected override void ConfigureCodeDocumentProcessor(RazorCodeDocumentProcesso
     public void WriteUsingDirective_NoSource_WritesContent()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new UsingDirectiveIntermediateNode()
@@ -45,7 +45,7 @@ public void WriteUsingDirective_NoSource_WritesContent()
     public void WriteUsingDirective_WithSource_WritesContentWithLinePragmaAndMapping()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var originalSpan = new SourceSpan("test.cshtml", 0, 0, 0, 6);
@@ -81,7 +81,7 @@ public void WriteUsingDirective_WithSource_WritesContentWithLinePragmaAndMapping
     public void WriteUsingDirective_WithSourceAndLineDirectives_WritesContentWithLinePragmaAndMapping()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var originalSpan = new SourceSpan("test.cshtml", 0, 0, 0, 6);
@@ -120,7 +120,7 @@ public void WriteUsingDirective_WithSourceAndLineDirectives_WritesContentWithLin
     public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpExpressionIntermediateNode();
@@ -143,7 +143,7 @@ public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
     public void WriteCSharpExpression_WritesLinePragma_WithSource()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpExpressionIntermediateNode()
@@ -178,7 +178,7 @@ public void WriteCSharpExpression_WritesLinePragma_WithSource()
     public void WriteCSharpExpression_WithExtensionNode_WritesPadding()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpExpressionIntermediateNode();
@@ -207,7 +207,7 @@ public void WriteCSharpExpression_WithExtensionNode_WritesPadding()
     public void WriteCSharpExpression_WithSource_WritesPadding()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpExpressionIntermediateNode()
@@ -246,7 +246,7 @@ public void WriteCSharpExpression_WithSource_WritesPadding()
     public void WriteCSharpCode_WhitespaceContentWithSource_WritesContent()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpCodeIntermediateNode()
@@ -280,7 +280,7 @@ public void WriteCSharpCode_WhitespaceContentWithSource_WritesContent()
     public void WriteCSharpCode_SkipsLinePragma_WithoutSource()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpCodeIntermediateNode();
@@ -303,7 +303,7 @@ public void WriteCSharpCode_SkipsLinePragma_WithoutSource()
     public void WriteCSharpCode_WritesLinePragma_WithSource()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpCodeIntermediateNode()
@@ -337,7 +337,7 @@ public void WriteCSharpCode_WritesLinePragma_WithSource()
     public void WriteCSharpCode_WritesPadding_WithSource()
     {
         // Arrange
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         var node = new CSharpCodeIntermediateNode()
@@ -370,14 +370,14 @@ public void WriteCSharpCode_WritesPadding_WithSource()
     [Fact]
     public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
     {
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
 
         var content = "<input checked=\"hello-world @false\" />";
         var source = TestRazorSourceDocument.Create(content);
         var codeDocument = ProjectEngine.CreateCodeDocument(source);
         var processor = CreateCodeDocumentProcessor(codeDocument);
         var documentNode = processor.GetDocumentNode();
-        var node = documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1] as CSharpExpressionAttributeValueIntermediateNode;
+        var node = (CSharpExpressionAttributeValueIntermediateNode) documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1];
 
         using var context = TestCodeRenderingContext.CreateDesignTime(source: source);
 
@@ -403,13 +403,13 @@ public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
     [Fact]
     public void WriteCSharpCodeAttributeValue_RendersCorrectly()
     {
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         var content = "<input checked=\"hello-world @if(@true){ }\" />";
         var sourceDocument = TestRazorSourceDocument.Create(content);
         var codeDocument = ProjectEngine.CreateCodeDocument(sourceDocument);
         var processor = CreateCodeDocumentProcessor(codeDocument);
         var documentNode = processor.GetDocumentNode();
-        var node = documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1] as CSharpCodeAttributeValueIntermediateNode;
+        var node = (CSharpCodeAttributeValueIntermediateNode) documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1];
 
         using var context = TestCodeRenderingContext.CreateDesignTime(source: sourceDocument);
 
@@ -435,13 +435,13 @@ public void WriteCSharpCodeAttributeValue_RendersCorrectly()
     [Fact]
     public void WriteCSharpCodeAttributeValue_WithExpression_RendersCorrectly()
     {
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         var content = "<input checked=\"hello-world @if(@true){ @false }\" />";
         var source = TestRazorSourceDocument.Create(content);
         var codeDocument = ProjectEngine.CreateCodeDocument(source);
         var processor = CreateCodeDocumentProcessor(codeDocument);
         var documentNode = processor.GetDocumentNode();
-        var node = documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1] as CSharpCodeAttributeValueIntermediateNode;
+        var node = (CSharpCodeAttributeValueIntermediateNode)documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1];
 
         using var context = TestCodeRenderingContext.CreateDesignTime(source: source);
 
@@ -484,7 +484,7 @@ Render Children
     [InlineData(@"\\SERVER/pages\test.cshtml",      @"\\SERVER\pages\test.cshtml")]
     public void LinePragma_Is_Adjusted_On_Windows(string fileName, string expectedFileName)
     {
-        var writer = new DesignTimeNodeWriter();
+        var writer = DesignTimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime();
 
         Assert.True(context.Options.RemapLinePragmaPathsOnWindows);
@@ -528,7 +528,7 @@ public void LinePragma_Is_Adjusted_On_Windows(string fileName, string expectedFi
     [InlineData(@"\\SERVER/pages\test.cshtml",      @"\\SERVER\pages\test.cshtml")]
     public void LinePragma_Enhanced_Is_Adjusted_On_Windows(string fileName, string expectedFileName)
     {
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateDesignTime(source: RazorSourceDocument.Create("", fileName));
 
         Assert.True(context.Options.RemapLinePragmaPathsOnWindows);
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/LiteralRuntimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/LiteralRuntimeNodeWriterTest.cs
index cbe91b970e1..db5f8d504af 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/LiteralRuntimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/LiteralRuntimeNodeWriterTest.cs
@@ -12,7 +12,7 @@ public class LiteralRuntimeNodeWriterTest
     public void WriteCSharpExpression_UsesWriteLiteral_WritesLinePragma_WithSource()
     {
         // Arrange
-        var writer = new LiteralRuntimeNodeWriter();
+        var writer = LiteralRuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new CSharpExpressionIntermediateNode();
@@ -43,7 +43,7 @@ public void WriteCSharpExpression_UsesWriteLiteral_WritesLinePragma_WithSource()
     public void WriteCSharpExpression_WithMultipleChildren()
     {
         // Arrange
-        var writer = new LiteralRuntimeNodeWriter();
+        var writer = LiteralRuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new CSharpExpressionIntermediateNode();
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
index c09ef8d3c8c..d4b10a0ba16 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
@@ -22,7 +22,7 @@ protected override void ConfigureCodeDocumentProcessor(RazorCodeDocumentProcesso
     public void WriteUsingDirective_NoSource_WritesContent()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new UsingDirectiveIntermediateNode()
@@ -46,7 +46,7 @@ public void WriteUsingDirective_NoSource_WritesContent()
     public void WriteUsingDirective_WithSource_WritesContentWithLinePragma()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new UsingDirectiveIntermediateNode()
@@ -77,7 +77,7 @@ public void WriteUsingDirective_WithSource_WritesContentWithLinePragma()
     public void WriteUsingDirective_WithSourceAndLineDirectives_WritesContentWithLinePragmaAndMapping()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new UsingDirectiveIntermediateNode()
@@ -111,10 +111,7 @@ public void WriteUsingDirective_WithSourceAndLineDirectives_WritesContentWithLin
     public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter()
-        {
-            WriteCSharpExpressionMethod = "Test"
-        };
+        var writer = new TestRuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -139,10 +136,7 @@ public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
     public void WriteCSharpExpression_WritesLinePragma_WithSource()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter()
-        {
-            WriteCSharpExpressionMethod = "Test"
-        };
+        var writer = new TestRuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -174,10 +168,7 @@ public void WriteCSharpExpression_WritesLinePragma_WithSource()
     public void WriteCSharpExpression_WithExtensionNode_WritesPadding()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter()
-        {
-            WriteCSharpExpressionMethod = "Test"
-        };
+        var writer = new TestRuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -207,10 +198,7 @@ iRender Children
     public void WriteCSharpExpression_WithSource_WritesPadding()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter()
-        {
-            WriteCSharpExpressionMethod = "Test"
-        };
+        var writer = new TestRuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -254,7 +242,7 @@ Render Children
     public void WriteCSharpCode_WhitespaceContent_DoesNothing()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new CSharpCodeIntermediateNode();
@@ -273,7 +261,7 @@ public void WriteCSharpCode_WhitespaceContent_DoesNothing()
     public void WriteCSharpCode_SkipsLinePragma_WithoutSource()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new CSharpCodeIntermediateNode();
@@ -296,7 +284,7 @@ public void WriteCSharpCode_SkipsLinePragma_WithoutSource()
     public void WriteCSharpCode_WritesLinePragma_WithSource()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new CSharpCodeIntermediateNode();
@@ -327,7 +315,7 @@ public void WriteCSharpCode_WritesLinePragma_WithSource()
     public void WriteCSharpCode_WritesPadding_WithSource()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new CSharpCodeIntermediateNode();
@@ -358,7 +346,7 @@ public void WriteCSharpCode_WritesPadding_WithSource()
     public void WriteHtmlLiteral_WithinMaxSize_WritesSingleLiteral()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         // Act
@@ -377,7 +365,7 @@ public void WriteHtmlLiteral_WithinMaxSize_WritesSingleLiteral()
     public void WriteHtmlLiteral_GreaterThanMaxSize_WritesMultipleLiterals()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         // Act
@@ -397,7 +385,7 @@ public void WriteHtmlLiteral_GreaterThanMaxSize_WritesMultipleLiterals()
     public void WriteHtmlLiteral_GreaterThanMaxSize_SingleEmojisSplit()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         // Act
@@ -417,7 +405,7 @@ public void WriteHtmlLiteral_GreaterThanMaxSize_SingleEmojisSplit()
     public void WriteHtmlLiteral_GreaterThanMaxSize_SequencedZeroWithJoinedEmojisSplit()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         // Act
@@ -439,7 +427,7 @@ public void WriteHtmlLiteral_GreaterThanMaxSize_SequencedZeroWithJoinedEmojisSpl
     public void WriteHtmlContent_RendersContentCorrectly()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new HtmlContentIntermediateNode();
@@ -461,7 +449,7 @@ public void WriteHtmlContent_RendersContentCorrectly()
     public void WriteHtmlContent_LargeStringLiteral_UsesMultipleWrites()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         using var context = TestCodeRenderingContext.CreateRuntime();
 
         var node = new HtmlContentIntermediateNode();
@@ -485,7 +473,7 @@ public void WriteHtmlContent_LargeStringLiteral_UsesMultipleWrites()
     public void WriteHtmlAttribute_RendersCorrectly()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         var content = "<input checked=\"hello-world @false\" />";
         var source = TestRazorSourceDocument.Create(content);
         var codeDocument = ProjectEngine.CreateCodeDocument(source);
@@ -514,7 +502,7 @@ Render Children
     public void WriteHtmlAttributeValue_RendersCorrectly()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         var content = "<input checked=\"hello-world @false\" />";
         var source = TestRazorSourceDocument.Create(content);
         var codeDocument = ProjectEngine.CreateCodeDocument(source);
@@ -540,7 +528,7 @@ public void WriteHtmlAttributeValue_RendersCorrectly()
     public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
         var content = "<input checked=\"hello-world @false\" />";
         var source = TestRazorSourceDocument.Create(content);
         var codeDocument = ProjectEngine.CreateCodeDocument(source);
@@ -574,7 +562,7 @@ public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
     public void WriteCSharpCodeAttributeValue_BuffersResult()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
 
         var content = "<input checked=\"hello-world @if(@true){ }\" />";
         var source = TestRazorSourceDocument.Create(content);
@@ -612,10 +600,7 @@ public void WriteCSharpCodeAttributeValue_BuffersResult()
     public void BeginWriterScope_UsesSpecifiedWriter_RendersCorrectly()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter()
-        {
-            PushWriterMethod = "TestPushWriter"
-        };
+        var writer = new TestRuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -635,10 +620,7 @@ public void BeginWriterScope_UsesSpecifiedWriter_RendersCorrectly()
     public void EndWriterScope_RendersCorrectly()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter()
-        {
-            PopWriterMethod = "TestPopWriter"
-        };
+        var writer = new TestRuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -668,4 +650,11 @@ public override void WriteNode(CodeTarget target, CodeRenderingContext context)
             throw new NotImplementedException();
         }
     }
+
+    public class TestRuntimeNodeWriter : RuntimeNodeWriter
+    {
+        public override string WriteCSharpExpressionMethod { get; } = "Test";
+        public override string PushWriterMethod { get; } = "TestPushWriter";
+        public override string PopWriterMethod { get; } = "TestPopWriter";
+    }
 }
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriterTest.cs
index 2bc29757852..6c9cedd6501 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriterTest.cs
@@ -19,7 +19,7 @@ protected override void ConfigureCodeDocumentProcessor(RazorCodeDocumentProcesso
     [Fact]
     public void WriteHtmlAttributeValue_RendersCorrectly()
     {
-        var writer = new TagHelperHtmlAttributeRuntimeNodeWriter();
+        var writer = TagHelperHtmlAttributeRuntimeNodeWriter.Instance;
 
         var content = "<input checked=\"hello-world @false\" />";
         var source = TestRazorSourceDocument.Create(content);
@@ -45,7 +45,7 @@ public void WriteHtmlAttributeValue_RendersCorrectly()
     [Fact]
     public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
     {
-        var writer = new TagHelperHtmlAttributeRuntimeNodeWriter();
+        var writer = TagHelperHtmlAttributeRuntimeNodeWriter.Instance;
         var content = "<input checked=\"hello-world @false\" />";
         var source = TestRazorSourceDocument.Create(content);
         var codeDocument = ProjectEngine.CreateCodeDocument(source);
@@ -78,7 +78,7 @@ public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
     [Fact]
     public void WriteCSharpCodeAttributeValue_BuffersResult()
     {
-        var writer = new TagHelperHtmlAttributeRuntimeNodeWriter();
+        var writer = TagHelperHtmlAttributeRuntimeNodeWriter.Instance;
 
         var content = "<input checked=\"hello-world @if(@true){ }\" />";
         var source = TestRazorSourceDocument.Create(content);
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
index e7783f3fddd..c8c71838d7e 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
@@ -27,11 +27,7 @@ public void WriteTemplate_WritesTemplateCode()
             TemplateTypeName = "global::TestTemplate"
         };
 
-        var nodeWriter = new RuntimeNodeWriter()
-        {
-            PushWriterMethod = "TestPushWriter",
-            PopWriterMethod = "TestPopWriter"
-        };
+        var nodeWriter = new TestRuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime(nodeWriter: nodeWriter);
 
@@ -49,4 +45,10 @@ Render Children
         var output = context.CodeWriter.GetText().ToString();
         Assert.Equal(expected, output);
     }
+
+    public class TestRuntimeNodeWriter : RuntimeNodeWriter
+    {
+        public override string PushWriterMethod { get; } = "TestPushWriter";
+        public override string PopWriterMethod { get; } = "TestPopWriter";
+    }
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DefaultCodeTarget.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DefaultCodeTarget.cs
index c2f7f24cdb7..44e5ed55eb6 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DefaultCodeTarget.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DefaultCodeTarget.cs
@@ -12,6 +12,6 @@ internal sealed class DefaultCodeTarget(
 {
     public override IntermediateNodeWriter CreateNodeWriter()
         => Options.DesignTime
-            ? new DesignTimeNodeWriter()
-            : new RuntimeNodeWriter();
+            ? DesignTimeNodeWriter.Instance
+            : RuntimeNodeWriter.Instance;
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.cs
index 6db086e2d11..2f419e5c9b9 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.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;
 using System.Diagnostics;
 using Microsoft.AspNetCore.Razor.Language.Extensions;
@@ -12,6 +10,8 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
 public class DesignTimeNodeWriter : IntermediateNodeWriter
 {
+    public static readonly DesignTimeNodeWriter Instance = new DesignTimeNodeWriter();
+
     public override void WriteUsingDirective(CodeRenderingContext context, UsingDirectiveIntermediateNode node)
     {
         if (node.Source is { FilePath: not null } sourceSpan)
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/IntermediateNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/IntermediateNodeWriter.cs
index 7dcc0bc60e3..a8d5dfdbc87 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/IntermediateNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/IntermediateNodeWriter.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;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
index 3be1fef2372..30bae12f2d0 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
@@ -1,11 +1,11 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
 internal class LiteralRuntimeNodeWriter : RuntimeNodeWriter
 {
-    public override string WriteCSharpExpressionMethod { get; set; } = "WriteLiteral";
+    public static new readonly LiteralRuntimeNodeWriter Instance = new LiteralRuntimeNodeWriter();
+
+    public override string WriteCSharpExpressionMethod { get; } = "WriteLiteral";
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
index 80fb96663c9..c6bcad746a1 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
@@ -4,7 +4,6 @@
 #nullable disable
 
 using System;
-using System.Globalization;
 using System.Linq;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 using Microsoft.AspNetCore.Razor.PooledObjects;
@@ -13,21 +12,23 @@ namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
 public class RuntimeNodeWriter : IntermediateNodeWriter
 {
-    public virtual string WriteCSharpExpressionMethod { get; set; } = "Write";
+    public static readonly RuntimeNodeWriter Instance = new RuntimeNodeWriter();
 
-    public virtual string WriteHtmlContentMethod { get; set; } = "WriteLiteral";
+    public virtual string WriteCSharpExpressionMethod { get; } = "Write";
 
-    public virtual string BeginWriteAttributeMethod { get; set; } = "BeginWriteAttribute";
+    public virtual string WriteHtmlContentMethod { get; } = "WriteLiteral";
 
-    public virtual string EndWriteAttributeMethod { get; set; } = "EndWriteAttribute";
+    public virtual string BeginWriteAttributeMethod { get; } = "BeginWriteAttribute";
 
-    public virtual string WriteAttributeValueMethod { get; set; } = "WriteAttributeValue";
+    public virtual string EndWriteAttributeMethod { get; } = "EndWriteAttribute";
 
-    public virtual string PushWriterMethod { get; set; } = "PushWriter";
+    public virtual string WriteAttributeValueMethod { get; } = "WriteAttributeValue";
 
-    public virtual string PopWriterMethod { get; set; } = "PopWriter";
+    public virtual string PushWriterMethod { get; } = "PushWriter";
 
-    public string TemplateTypeName { get; set; } = "Microsoft.AspNetCore.Mvc.Razor.HelperResult";
+    public virtual string PopWriterMethod { get; } = "PopWriter";
+
+    public string TemplateTypeName { get; } = "Microsoft.AspNetCore.Mvc.Razor.HelperResult";
 
     public override void WriteUsingDirective(CodeRenderingContext context, UsingDirectiveIntermediateNode node)
     {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
index 3ce267685f3..a9f8b432319 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
@@ -1,11 +1,11 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 namespace Microsoft.AspNetCore.Razor.Language.CodeGeneration;
 
 internal class TagHelperHtmlAttributeRuntimeNodeWriter : RuntimeNodeWriter
 {
-    public override string WriteAttributeValueMethod { get; set; } = "AddHtmlAttributeValue";
+    public static new readonly TagHelperHtmlAttributeRuntimeNodeWriter Instance = new TagHelperHtmlAttributeRuntimeNodeWriter();
+
+    public override string WriteAttributeValueMethod { get; } = "AddHtmlAttributeValue";
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Extensions/DefaultTagHelperTargetExtension.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Extensions/DefaultTagHelperTargetExtension.cs
index e1f0c661fab..d0bc07de67f 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Extensions/DefaultTagHelperTargetExtension.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/Extensions/DefaultTagHelperTargetExtension.cs
@@ -113,7 +113,7 @@ public void WriteTagHelperBody(CodeRenderingContext context, DefaultTagHelperBod
             using (context.CodeWriter.BuildAsyncLambda())
             {
                 // We remove and redirect writers so TagHelper authors can retrieve content.
-                context.RenderChildren(node, new RuntimeNodeWriter());
+                context.RenderChildren(node, RuntimeNodeWriter.Instance);
             }
 
             context.CodeWriter.WriteEndMethodInvocation();
@@ -236,7 +236,7 @@ child is CSharpCodeAttributeValueIntermediateNode ||
                     .Write(attributeValueStyleParameter)
                     .WriteEndMethodInvocation();
 
-                context.RenderChildren(node, new TagHelperHtmlAttributeRuntimeNodeWriter());
+                context.RenderChildren(node, TagHelperHtmlAttributeRuntimeNodeWriter.Instance);
 
                 context.CodeWriter
                     .WriteMethodInvocation(
@@ -255,7 +255,7 @@ child is CSharpCodeAttributeValueIntermediateNode ||
                 // We're building a writing scope around the provided chunks which captures everything written from the
                 // page. Therefore, we do not want to write to any other buffer since we're using the pages buffer to
                 // ensure we capture all content that's written, directly or indirectly.
-                context.RenderChildren(node, new RuntimeNodeWriter());
+                context.RenderChildren(node, RuntimeNodeWriter.Instance);
 
                 context.CodeWriter
                     .WriteStartAssignment(StringValueBufferVariableName)
@@ -358,7 +358,7 @@ public void WriteTagHelperProperty(CodeRenderingContext context, DefaultTagHelpe
             {
                 context.CodeWriter.WriteMethodInvocation(BeginWriteTagHelperAttributeMethodName);
 
-                context.RenderChildren(node, new LiteralRuntimeNodeWriter());
+                context.RenderChildren(node, LiteralRuntimeNodeWriter.Instance);
 
                 context.CodeWriter
                     .WriteStartAssignment(StringValueBufferVariableName)
diff --git a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/CodeGeneration/TestCodeRenderingContext.cs b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/CodeGeneration/TestCodeRenderingContext.cs
index 87293cb7e11..870132e673c 100644
--- a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/CodeGeneration/TestCodeRenderingContext.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/CodeGeneration/TestCodeRenderingContext.cs
@@ -15,7 +15,7 @@ public static CodeRenderingContext CreateDesignTime(
         RazorSourceDocument source = null,
         IntermediateNodeWriter nodeWriter = null)
     {
-        nodeWriter ??= new RuntimeNodeWriter();
+        nodeWriter ??= RuntimeNodeWriter.Instance;
         source ??= TestRazorSourceDocument.Create();
         var documentNode = new DocumentIntermediateNode();
 
@@ -33,7 +33,7 @@ public static CodeRenderingContext CreateRuntime(
         RazorSourceDocument source = null,
         IntermediateNodeWriter nodeWriter = null)
     {
-        nodeWriter ??= new RuntimeNodeWriter();
+        nodeWriter ??= RuntimeNodeWriter.Instance;
         source ??= TestRazorSourceDocument.Create();
         var documentNode = new DocumentIntermediateNode();
 

From 443c81cafffe86076a293aa727196a462e72a57c Mon Sep 17 00:00:00 2001
From: Todd Grunke <toddgrun@microsoft.com>
Date: Fri, 17 Oct 2025 18:47:46 -0700
Subject: [PATCH 2/5] Get rid of backing fields

---
 .../test/CodeGeneration/RuntimeNodeWriterTest.cs |  6 +++---
 .../Extensions/TemplateTargetExtensionTest.cs    |  4 ++--
 .../CodeGeneration/LiteralRuntimeNodeWriter.cs   |  2 +-
 .../Language/CodeGeneration/RuntimeNodeWriter.cs | 16 ++++++++--------
 .../TagHelperHtmlAttributeRuntimeNodeWriter.cs   |  2 +-
 5 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
index d4b10a0ba16..fa413af9e2e 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
@@ -653,8 +653,8 @@ public override void WriteNode(CodeTarget target, CodeRenderingContext context)
 
     public class TestRuntimeNodeWriter : RuntimeNodeWriter
     {
-        public override string WriteCSharpExpressionMethod { get; } = "Test";
-        public override string PushWriterMethod { get; } = "TestPushWriter";
-        public override string PopWriterMethod { get; } = "TestPopWriter";
+        public override string WriteCSharpExpressionMethod { get => "Test"; }
+        public override string PushWriterMethod { get => "TestPushWriter"; }
+        public override string PopWriterMethod { get => "TestPopWriter"; }
     }
 }
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
index c8c71838d7e..4e220629912 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
@@ -48,7 +48,7 @@ Render Children
 
     public class TestRuntimeNodeWriter : RuntimeNodeWriter
     {
-        public override string PushWriterMethod { get; } = "TestPushWriter";
-        public override string PopWriterMethod { get; } = "TestPopWriter";
+        public override string PushWriterMethod { get => "TestPushWriter"; }
+        public override string PopWriterMethod { get => "TestPopWriter"; }
     }
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
index 30bae12f2d0..aab9e982edb 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
@@ -7,5 +7,5 @@ internal class LiteralRuntimeNodeWriter : RuntimeNodeWriter
 {
     public static new readonly LiteralRuntimeNodeWriter Instance = new LiteralRuntimeNodeWriter();
 
-    public override string WriteCSharpExpressionMethod { get; } = "WriteLiteral";
+    public override string WriteCSharpExpressionMethod { get => "WriteLiteral"; }
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
index c6bcad746a1..5d9b2714dd7 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
@@ -14,21 +14,21 @@ public class RuntimeNodeWriter : IntermediateNodeWriter
 {
     public static readonly RuntimeNodeWriter Instance = new RuntimeNodeWriter();
 
-    public virtual string WriteCSharpExpressionMethod { get; } = "Write";
+    public virtual string WriteCSharpExpressionMethod { get => "Write"; }
 
-    public virtual string WriteHtmlContentMethod { get; } = "WriteLiteral";
+    public virtual string WriteHtmlContentMethod { get => "WriteLiteral"; }
 
-    public virtual string BeginWriteAttributeMethod { get; } = "BeginWriteAttribute";
+    public virtual string BeginWriteAttributeMethod { get => "BeginWriteAttribute"; }
 
-    public virtual string EndWriteAttributeMethod { get; } = "EndWriteAttribute";
+    public virtual string EndWriteAttributeMethod { get => "EndWriteAttribute"; }
 
-    public virtual string WriteAttributeValueMethod { get; } = "WriteAttributeValue";
+    public virtual string WriteAttributeValueMethod { get => "WriteAttributeValue"; }
 
-    public virtual string PushWriterMethod { get; } = "PushWriter";
+    public virtual string PushWriterMethod { get => "PushWriter"; }
 
-    public virtual string PopWriterMethod { get; } = "PopWriter";
+    public virtual string PopWriterMethod { get => "PopWriter"; }
 
-    public string TemplateTypeName { get; } = "Microsoft.AspNetCore.Mvc.Razor.HelperResult";
+    public string TemplateTypeName { get => "Microsoft.AspNetCore.Mvc.Razor.HelperResult"; }
 
     public override void WriteUsingDirective(CodeRenderingContext context, UsingDirectiveIntermediateNode node)
     {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
index a9f8b432319..a43517eb638 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
@@ -7,5 +7,5 @@ internal class TagHelperHtmlAttributeRuntimeNodeWriter : RuntimeNodeWriter
 {
     public static new readonly TagHelperHtmlAttributeRuntimeNodeWriter Instance = new TagHelperHtmlAttributeRuntimeNodeWriter();
 
-    public override string WriteAttributeValueMethod { get; } = "AddHtmlAttributeValue";
+    public override string WriteAttributeValueMethod { get => "AddHtmlAttributeValue"; }
 }

From 522c327cad2bafb5533a8ee6c13310a574de7559 Mon Sep 17 00:00:00 2001
From: Todd Grunke <toddgrun@microsoft.com>
Date: Sat, 18 Oct 2025 06:33:10 -0700
Subject: [PATCH 3/5] Formatting

---
 .../test/CodeGeneration/DesignTimeNodeWriterTest.cs           | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs
index 43d9bced96f..5cab7f66e77 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/DesignTimeNodeWriterTest.cs
@@ -377,7 +377,7 @@ public void WriteCSharpExpressionAttributeValue_RendersCorrectly()
         var codeDocument = ProjectEngine.CreateCodeDocument(source);
         var processor = CreateCodeDocumentProcessor(codeDocument);
         var documentNode = processor.GetDocumentNode();
-        var node = (CSharpExpressionAttributeValueIntermediateNode) documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1];
+        var node = (CSharpExpressionAttributeValueIntermediateNode)documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1];
 
         using var context = TestCodeRenderingContext.CreateDesignTime(source: source);
 
@@ -409,7 +409,7 @@ public void WriteCSharpCodeAttributeValue_RendersCorrectly()
         var codeDocument = ProjectEngine.CreateCodeDocument(sourceDocument);
         var processor = CreateCodeDocumentProcessor(codeDocument);
         var documentNode = processor.GetDocumentNode();
-        var node = (CSharpCodeAttributeValueIntermediateNode) documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1];
+        var node = (CSharpCodeAttributeValueIntermediateNode)documentNode.Children.OfType<HtmlAttributeIntermediateNode>().Single().Children[1];
 
         using var context = TestCodeRenderingContext.CreateDesignTime(source: sourceDocument);
 

From acd1a2a89dff1e8e76302538f992519c5ada0eb1 Mon Sep 17 00:00:00 2001
From: Todd Grunke <toddgrun@microsoft.com>
Date: Mon, 20 Oct 2025 13:58:16 -0700
Subject: [PATCH 4/5] 1) Get rid of TestRuntimeNodeWriter 2) Make classes that
 expose static Instance have private (or protected) constructors 3) Change
 from "{ get; => blah; }" syntax to "=> blah;" syntax.

---
 .../CodeGeneration/RuntimeNodeWriterTest.cs   | 31 +++++++------------
 .../Extensions/TemplateTargetExtensionTest.cs | 12 ++-----
 .../CodeGeneration/DesignTimeNodeWriter.cs    |  4 +++
 .../LiteralRuntimeNodeWriter.cs               |  6 +++-
 .../CodeGeneration/RuntimeNodeWriter.cs       | 20 +++++++-----
 ...TagHelperHtmlAttributeRuntimeNodeWriter.cs |  6 +++-
 6 files changed, 41 insertions(+), 38 deletions(-)

diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
index fa413af9e2e..f52654bbb3d 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
@@ -111,7 +111,7 @@ public void WriteUsingDirective_WithSourceAndLineDirectives_WritesContentWithLin
     public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
     {
         // Arrange
-        var writer = new TestRuntimeNodeWriter();
+        var writer = new RuntimeNodeWriter();
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -125,7 +125,7 @@ public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
         // Assert
         var csharp = context.CodeWriter.GetText().ToString();
         Assert.Equal(
-@"Test(
+@"Write(
 i++);
 ",
             csharp,
@@ -136,7 +136,7 @@ public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
     public void WriteCSharpExpression_WritesLinePragma_WithSource()
     {
         // Arrange
-        var writer = new TestRuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -150,7 +150,7 @@ public void WriteCSharpExpression_WritesLinePragma_WithSource()
         // Assert
         var csharp = context.CodeWriter.GetText().ToString();
         Assert.Equal(
-@"Test(
+@"Write(
 #nullable restore
 #line (1,1)-(1,4) ""test.cshtml""
 i++
@@ -168,7 +168,7 @@ public void WriteCSharpExpression_WritesLinePragma_WithSource()
     public void WriteCSharpExpression_WithExtensionNode_WritesPadding()
     {
         // Arrange
-        var writer = new TestRuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -186,7 +186,7 @@ public void WriteCSharpExpression_WithExtensionNode_WritesPadding()
         // Assert
         var csharp = context.CodeWriter.GetText().ToString();
         Assert.Equal(
-@"Test(
+@"Write(
 iRender Children
 ++);
 ",
@@ -198,7 +198,7 @@ iRender Children
     public void WriteCSharpExpression_WithSource_WritesPadding()
     {
         // Arrange
-        var writer = new TestRuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -216,7 +216,7 @@ public void WriteCSharpExpression_WithSource_WritesPadding()
         // Assert
         var csharp = context.CodeWriter.GetText().ToString();
         Assert.Equal(
-@"Test(
+@"Write(
 #nullable restore
 #line (1,1)-(1,2) ""test.cshtml""
 i
@@ -600,7 +600,7 @@ public void WriteCSharpCodeAttributeValue_BuffersResult()
     public void BeginWriterScope_UsesSpecifiedWriter_RendersCorrectly()
     {
         // Arrange
-        var writer = new TestRuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -610,7 +610,7 @@ public void BeginWriterScope_UsesSpecifiedWriter_RendersCorrectly()
         // Assert
         var csharp = context.CodeWriter.GetText().ToString();
         Assert.Equal(
-@"TestPushWriter(MyWriter);
+@"PushWriter(MyWriter);
 ",
             csharp,
             ignoreLineEndingDifferences: true);
@@ -620,7 +620,7 @@ public void BeginWriterScope_UsesSpecifiedWriter_RendersCorrectly()
     public void EndWriterScope_RendersCorrectly()
     {
         // Arrange
-        var writer = new TestRuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
 
         using var context = TestCodeRenderingContext.CreateRuntime();
 
@@ -630,7 +630,7 @@ public void EndWriterScope_RendersCorrectly()
         // Assert
         var csharp = context.CodeWriter.GetText().ToString();
         Assert.Equal(
-@"TestPopWriter();
+@"PopWriter();
 ",
             csharp,
             ignoreLineEndingDifferences: true);
@@ -650,11 +650,4 @@ public override void WriteNode(CodeTarget target, CodeRenderingContext context)
             throw new NotImplementedException();
         }
     }
-
-    public class TestRuntimeNodeWriter : RuntimeNodeWriter
-    {
-        public override string WriteCSharpExpressionMethod { get => "Test"; }
-        public override string PushWriterMethod { get => "TestPushWriter"; }
-        public override string PopWriterMethod { get => "TestPopWriter"; }
-    }
 }
diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
index 4e220629912..6c022489a40 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/TemplateTargetExtensionTest.cs
@@ -27,7 +27,7 @@ public void WriteTemplate_WritesTemplateCode()
             TemplateTypeName = "global::TestTemplate"
         };
 
-        var nodeWriter = new TestRuntimeNodeWriter();
+        var nodeWriter = RuntimeNodeWriter.Instance;
 
         using var context = TestCodeRenderingContext.CreateRuntime(nodeWriter: nodeWriter);
 
@@ -36,19 +36,13 @@ public void WriteTemplate_WritesTemplateCode()
 
         // Assert
         var expected = @"item => new global::TestTemplate(async(__razor_template_writer) => {
-    TestPushWriter(__razor_template_writer);
+    PushWriter(__razor_template_writer);
     Render Children
-    TestPopWriter();
+    PopWriter();
 }
 )";
 
         var output = context.CodeWriter.GetText().ToString();
         Assert.Equal(expected, output);
     }
-
-    public class TestRuntimeNodeWriter : RuntimeNodeWriter
-    {
-        public override string PushWriterMethod { get => "TestPushWriter"; }
-        public override string PopWriterMethod { get => "TestPopWriter"; }
-    }
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.cs
index 2f419e5c9b9..3e9868eea69 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/DesignTimeNodeWriter.cs
@@ -12,6 +12,10 @@ public class DesignTimeNodeWriter : IntermediateNodeWriter
 {
     public static readonly DesignTimeNodeWriter Instance = new DesignTimeNodeWriter();
 
+    private DesignTimeNodeWriter()
+    {
+    }
+
     public override void WriteUsingDirective(CodeRenderingContext context, UsingDirectiveIntermediateNode node)
     {
         if (node.Source is { FilePath: not null } sourceSpan)
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
index aab9e982edb..6631ad30f20 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/LiteralRuntimeNodeWriter.cs
@@ -7,5 +7,9 @@ internal class LiteralRuntimeNodeWriter : RuntimeNodeWriter
 {
     public static new readonly LiteralRuntimeNodeWriter Instance = new LiteralRuntimeNodeWriter();
 
-    public override string WriteCSharpExpressionMethod { get => "WriteLiteral"; }
+    private LiteralRuntimeNodeWriter()
+    {
+    }
+
+    public override string WriteCSharpExpressionMethod => "WriteLiteral";
 }
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
index 5d9b2714dd7..c01b6bab741 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/RuntimeNodeWriter.cs
@@ -14,21 +14,25 @@ public class RuntimeNodeWriter : IntermediateNodeWriter
 {
     public static readonly RuntimeNodeWriter Instance = new RuntimeNodeWriter();
 
-    public virtual string WriteCSharpExpressionMethod { get => "Write"; }
+    public virtual string WriteCSharpExpressionMethod => "Write";
 
-    public virtual string WriteHtmlContentMethod { get => "WriteLiteral"; }
+    public virtual string WriteHtmlContentMethod => "WriteLiteral";
 
-    public virtual string BeginWriteAttributeMethod { get => "BeginWriteAttribute"; }
+    public virtual string BeginWriteAttributeMethod => "BeginWriteAttribute";
 
-    public virtual string EndWriteAttributeMethod { get => "EndWriteAttribute"; }
+    public virtual string EndWriteAttributeMethod => "EndWriteAttribute";
 
-    public virtual string WriteAttributeValueMethod { get => "WriteAttributeValue"; }
+    public virtual string WriteAttributeValueMethod => "WriteAttributeValue";
 
-    public virtual string PushWriterMethod { get => "PushWriter"; }
+    public virtual string PushWriterMethod => "PushWriter";
 
-    public virtual string PopWriterMethod { get => "PopWriter"; }
+    public virtual string PopWriterMethod => "PopWriter";
 
-    public string TemplateTypeName { get => "Microsoft.AspNetCore.Mvc.Razor.HelperResult"; }
+    public const string TemplateTypeName = "Microsoft.AspNetCore.Mvc.Razor.HelperResult";
+
+    protected RuntimeNodeWriter()
+    {
+    }
 
     public override void WriteUsingDirective(CodeRenderingContext context, UsingDirectiveIntermediateNode node)
     {
diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
index a43517eb638..df89c0a39d5 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/CodeGeneration/TagHelperHtmlAttributeRuntimeNodeWriter.cs
@@ -7,5 +7,9 @@ internal class TagHelperHtmlAttributeRuntimeNodeWriter : RuntimeNodeWriter
 {
     public static new readonly TagHelperHtmlAttributeRuntimeNodeWriter Instance = new TagHelperHtmlAttributeRuntimeNodeWriter();
 
-    public override string WriteAttributeValueMethod { get => "AddHtmlAttributeValue"; }
+    public override string WriteAttributeValueMethod => "AddHtmlAttributeValue";
+
+    private TagHelperHtmlAttributeRuntimeNodeWriter()
+    {
+    }
 }

From 11b5e4f7ab1ac9e2b3db7b6e13d9b3446946d11e Mon Sep 17 00:00:00 2001
From: Todd Grunke <toddgrun@microsoft.com>
Date: Mon, 20 Oct 2025 16:34:14 -0700
Subject: [PATCH 5/5] Fix build break after making ctors less accessible

---
 .../test/CodeGeneration/RuntimeNodeWriterTest.cs                | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
index f52654bbb3d..2384f4452b6 100644
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/CodeGeneration/RuntimeNodeWriterTest.cs
@@ -111,7 +111,7 @@ public void WriteUsingDirective_WithSourceAndLineDirectives_WritesContentWithLin
     public void WriteCSharpExpression_SkipsLinePragma_WithoutSource()
     {
         // Arrange
-        var writer = new RuntimeNodeWriter();
+        var writer = RuntimeNodeWriter.Instance;
 
         using var context = TestCodeRenderingContext.CreateRuntime();