Allow components in global namespace

src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions/test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent_DesignTime.codegen.cs

@@ -1,6 +1,6 @@
 // <auto-generated/>
 #pragma warning disable 1591
-namespace __GeneratedComponent
+namespace TestFiles.IntegrationTests.CodeGenerationIntegrationTest
 {
     #line default
     using global::System;
@@ -11,7 +11,7 @@ namespace __GeneratedComponent
     #line default
     #line hidden
     #nullable restore
-    public partial class AspNetCore_3708c9fcd2e1ecb6cbaba92bcc60927f830690f42092c4aa1a7275c2f37020fd : global::Microsoft.AspNetCore.Components.ComponentBase, IDisposable
+    public partial class BasicComponent : global::Microsoft.AspNetCore.Components.ComponentBase, IDisposable
     #nullable disable
     {
         #pragma warning disable 219

src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions/test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent_DesignTime.ir.txt

@@ -1,11 +1,11 @@
 Document - 
-    NamespaceDeclaration -  - __GeneratedComponent
+    NamespaceDeclaration -  - TestFiles.IntegrationTests.CodeGenerationIntegrationTest
         UsingDirective - (1:0,1 [20] ) - global::System
         UsingDirective - (24:1,1 [40] ) - global::System.Collections.Generic
         UsingDirective - (67:2,1 [25] ) - global::System.Linq
         UsingDirective - (95:3,1 [36] ) - global::System.Threading.Tasks
         UsingDirective - (134:4,1 [45] ) - global::Microsoft.AspNetCore.Components
-        ClassDeclaration -  - public partial - AspNetCore_3708c9fcd2e1ecb6cbaba92bcc60927f830690f42092c4aa1a7275c2f37020fd - global::Microsoft.AspNetCore.Components.ComponentBase - IDisposable
+        ClassDeclaration -  - public partial - BasicComponent - global::Microsoft.AspNetCore.Components.ComponentBase - IDisposable
             DesignTimeDirective - 
                 DirectiveToken - (12:0,12 [11] BasicComponent.cshtml) - IDisposable
             CSharpCode - 

src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions/test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent_DesignTime.mappings.txt

@@ -1,23 +1,23 @@
 Source Location: (12:0,12 [11] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent.cshtml)
 |IDisposable|
-Generated Location: (813:21,0 [11] )
+Generated Location: (788:21,0 [11] )
 |IDisposable|
 
 Source Location: (38:1,13 [15] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent.cshtml)
 |this.ToString()|
-Generated Location: (1413:39,13 [15] )
+Generated Location: (1388:39,13 [15] )
 |this.ToString()|
 
 Source Location: (79:3,5 [29] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent.cshtml)
 |string.Format("{0}", "Hello")|
-Generated Location: (1610:47,6 [29] )
+Generated Location: (1585:47,6 [29] )
 |string.Format("{0}", "Hello")|
 
 Source Location: (132:6,12 [37] TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent.cshtml)
 |
     void IDisposable.Dispose(){ }
 |
-Generated Location: (1862:56,12 [37] )
+Generated Location: (1837:56,12 [37] )
 |
     void IDisposable.Dispose(){ }
 |

src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions/test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent_Runtime.codegen.cs

@@ -1,7 +1,7 @@
 #pragma checksum "TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent.cshtml" "{8829d00f-11b8-4213-878b-770e8597ac16}" "3708c9fcd2e1ecb6cbaba92bcc60927f830690f42092c4aa1a7275c2f37020fd"
 // <auto-generated/>
 #pragma warning disable 1591
-namespace __GeneratedComponent
+namespace TestFiles.IntegrationTests.CodeGenerationIntegrationTest
 {
     #line default
     using global::System;
@@ -12,7 +12,7 @@ namespace __GeneratedComponent
     #line default
     #line hidden
     #nullable restore
-    public partial class AspNetCore_3708c9fcd2e1ecb6cbaba92bcc60927f830690f42092c4aa1a7275c2f37020fd : global::Microsoft.AspNetCore.Components.ComponentBase, IDisposable
+    public partial class BasicComponent : global::Microsoft.AspNetCore.Components.ComponentBase, IDisposable
     #nullable disable
     {
         #pragma warning disable 1998

src/Compiler/Microsoft.AspNetCore.Mvc.Razor.Extensions/test/TestFiles/IntegrationTests/CodeGenerationIntegrationTest/BasicComponent_Runtime.ir.txt

@@ -1,11 +1,11 @@
 Document - 
-    NamespaceDeclaration -  - __GeneratedComponent
+    NamespaceDeclaration -  - TestFiles.IntegrationTests.CodeGenerationIntegrationTest
         UsingDirective - (1:0,1 [22] ) - global::System
         UsingDirective - (24:1,1 [42] ) - global::System.Collections.Generic
         UsingDirective - (67:2,1 [27] ) - global::System.Linq
         UsingDirective - (95:3,1 [38] ) - global::System.Threading.Tasks
         UsingDirective - (134:4,1 [45] ) - global::Microsoft.AspNetCore.Components
-        ClassDeclaration -  - public partial - AspNetCore_3708c9fcd2e1ecb6cbaba92bcc60927f830690f42092c4aa1a7275c2f37020fd - global::Microsoft.AspNetCore.Components.ComponentBase - IDisposable
+        ClassDeclaration -  - public partial - BasicComponent - global::Microsoft.AspNetCore.Components.ComponentBase - IDisposable
             MethodDeclaration -  - protected override - void - BuildRenderTree
                 MarkupElement - (25:1,0 [91] BasicComponent.cshtml) - div
                     HtmlAttribute - (29:1,4 [25] BasicComponent.cshtml) -  class=" - "

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/Extensions/MetadataAttributePassTest.cs

@@ -133,7 +133,20 @@ public void Execute_NoNamespaceSet_Noops()
         pass.Execute(codeDocument, irDocument);
 
         // Assert
-        SingleChild<NamespaceDeclarationIntermediateNode>(irDocument);
+        Assert.Equal(2, irDocument.Children.Count);
+
+        var item = Assert.IsType<RazorCompiledItemAttributeIntermediateNode>(irDocument.Children[0]);
+        Assert.Equal("/test.cshtml", item.Identifier);
+        Assert.Equal("test", item.Kind);
+        Assert.Equal("Test", item.TypeName);
+
+        Assert.Equal(2, @namespace.Children.Count);
+        var checksum = Assert.IsType<RazorSourceChecksumAttributeIntermediateNode>(@namespace.Children[0]);
+        Assert.Equal(CodeAnalysis.Text.SourceHashAlgorithm.Sha256, checksum.ChecksumAlgorithm);
+        Assert.Equal("/test.cshtml", checksum.Identifier);
+
+        var foundClass = Assert.IsType<ClassDeclarationIntermediateNode>(@namespace.Children[1]);
+        Assert.Equal("Test", foundClass.ClassName);
     }
 
     [Fact]

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs

@@ -9633,6 +9633,39 @@ @preservewhitespace false
 
     #endregion
 
+    #region Namespace
+
+    [IntegrationTestFact]
+    public void EmptyRootNamespace()
+    {
+        DefaultRootNamespace = string.Empty;
+
+        AdditionalSyntaxTrees.Add(Parse("""
+            using Microsoft.AspNetCore.Components;
+            public class Component1 : ComponentBase { }
+            namespace Shared
+            {
+                public class Component2 : ComponentBase { }
+            }
+            class C
+            {
+                void M1(TestComponent t) { }
+                void M2(global::TestComponent t) { }
+            }
+            """));
+        var generated = CompileToCSharp("""
+            <h1>Generated</h1>
+            <Component1 />
+            <Shared.Component2 />
+            """);
+
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        CompileToAssembly(generated);
+    }
+
+    #endregion
+
     #region "CSS scoping"
     [IntegrationTestFact]
     public void Component_WithCssScope()

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/EmptyRootNamespace/TestComponent.codegen.cs

@@ -0,0 +1,50 @@
+// <auto-generated/>
+#pragma warning disable 1591
+
+    #line default
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    #line default
+    #line hidden
+    #nullable restore
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    #nullable disable
+    {
+        #pragma warning disable 219
+        private void __RazorDirectiveTokenHelpers__() {
+        }
+        #pragma warning restore 219
+        #pragma warning disable 0414
+        private static object __o = null;
+        #pragma warning restore 0414
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __builder.AddAttribute(-1, "ChildContent", (global::Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+            }
+            ));
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Component1);
+
+#line default
+#line hidden
+#nullable disable
+            __builder.AddAttribute(-1, "ChildContent", (global::Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+            }
+            ));
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Shared.Component2);
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+    }
+
+#pragma warning restore 1591

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/EmptyRootNamespace/TestComponent.ir.txt

@@ -0,0 +1,25 @@
+Document - 
+    NamespaceDeclaration -  - 
+        UsingDirective - (3:1,1 [20] ) - global::System
+        UsingDirective - (26:2,1 [40] ) - global::System.Collections.Generic
+        UsingDirective - (69:3,1 [25] ) - global::System.Linq
+        UsingDirective - (97:4,1 [36] ) - global::System.Threading.Tasks
+        UsingDirective - (136:5,1 [45] ) - global::Microsoft.AspNetCore.Components
+        ClassDeclaration -  - public partial - TestComponent - global::Microsoft.AspNetCore.Components.ComponentBase - 
+            DesignTimeDirective - 
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning disable 0414
+            CSharpCode - 
+                IntermediateToken -  - CSharp - private static object __o = null;
+            CSharpCode - 
+                IntermediateToken -  - CSharp - #pragma warning restore 0414
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                MarkupElement - (0:0,0 [18] x:\dir\subdir\Test\TestComponent.cshtml) - h1
+                    HtmlContent - (4:0,4 [9] x:\dir\subdir\Test\TestComponent.cshtml)
+                        LazyIntermediateToken - (4:0,4 [9] x:\dir\subdir\Test\TestComponent.cshtml) - Html - Generated
+                HtmlContent - (18:0,18 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (18:0,18 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                Component - (20:1,0 [14] x:\dir\subdir\Test\TestComponent.cshtml) - Component1
+                HtmlContent - (34:1,14 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (34:1,14 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                Component - (36:2,0 [21] x:\dir\subdir\Test\TestComponent.cshtml) - Shared.Component2

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/EmptyRootNamespace/TestComponent.codegen.cs

@@ -0,0 +1,29 @@
+// <auto-generated/>
+#pragma warning disable 1591
+
+    #line default
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    #line default
+    #line hidden
+    #nullable restore
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    #nullable disable
+    {
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __builder.AddMarkupContent(0, "<h1>Generated</h1>\r\n");
+            __builder.OpenComponent<global::Component1>(1);
+            __builder.CloseComponent();
+            __builder.AddMarkupContent(2, "\r\n");
+            __builder.OpenComponent<global::Shared.Component2>(3);
+            __builder.CloseComponent();
+        }
+        #pragma warning restore 1998
+    }
+
+#pragma warning restore 1591

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/EmptyRootNamespace/TestComponent.ir.txt

@@ -0,0 +1,14 @@
+Document - 
+    NamespaceDeclaration -  - 
+        UsingDirective - (3:1,1 [22] ) - global::System
+        UsingDirective - (26:2,1 [42] ) - global::System.Collections.Generic
+        UsingDirective - (69:3,1 [27] ) - global::System.Linq
+        UsingDirective - (97:4,1 [38] ) - global::System.Threading.Tasks
+        UsingDirective - (136:5,1 [47] ) - global::Microsoft.AspNetCore.Components
+        ClassDeclaration -  - public partial - TestComponent - global::Microsoft.AspNetCore.Components.ComponentBase - 
+            MethodDeclaration -  - protected override - void - BuildRenderTree
+                MarkupBlock -  - <h1>Generated</h1>\n
+                Component - (20:1,0 [14] x:\dir\subdir\Test\TestComponent.cshtml) - Component1
+                HtmlContent - (34:1,14 [2] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (34:1,14 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
+                Component - (36:2,0 [21] x:\dir\subdir\Test\TestComponent.cshtml) - Shared.Component2

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/BindTagHelperDescriptorProvider.cs

@@ -343,7 +343,8 @@ private ref struct DisplayNameHelper(INamedTypeSymbol type)
             private (string Type, string Namespace)? _names;
 
             public (string Type, string Namespace) GetNames()
-                => _names ??= (_type.ToDisplayString(), _type.ContainingNamespace.ToDisplayString());
+                => _names ??= (_type.ToDisplayString(),
+                    _type.ContainingNamespace.ToDisplayString(SymbolExtensions.FullNameTypeDisplayFormat));
         }
 
         private static TagHelperDescriptor CreateElementBindTagHelper(

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/ComponentTagHelperDescriptorProvider.cs

@@ -115,8 +115,10 @@ private static TagHelperDescriptor CreateNameMatchingDescriptor(
 
             if (fullyQualified)
             {
-                var containingNamespace = type.ContainingNamespace.ToDisplayString();
-                var fullName = $"{containingNamespace}.{type.Name}";
+                var containingNamespace = type.ContainingNamespace.ToDisplayString(SymbolExtensions.FullNameTypeDisplayFormat);
+                var fullName = string.IsNullOrEmpty(containingNamespace)
+                    ? type.Name
+                    : $"{containingNamespace}.{type.Name}";
 
                 builder.TagMatchingRule(r =>
                 {
@@ -125,7 +127,8 @@ private static TagHelperDescriptor CreateNameMatchingDescriptor(
 
                 metadata.Add(ComponentMetadata.Component.NameMatchKey, ComponentMetadata.Component.FullyQualifiedNameMatch);
             }
-            else
+            // If the component is in the global namespace, skip adding this rule which is the same as the fully qualified one.
+            else if (!type.ContainingNamespace.IsGlobalNamespace)
             {
                 builder.TagMatchingRule(r =>
                 {

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/CSharp/EventHandlerTagHelperDescriptorProvider.cs

@@ -101,7 +101,8 @@ private ref struct DisplayNameHelper(INamedTypeSymbol type)
 
             public (string Type, string Namespace) GetNames()
             {
-                _names ??= (_type.ToDisplayString(), _type.ContainingNamespace.ToDisplayString());
+                _names ??= (_type.ToDisplayString(),
+                    _type.ContainingNamespace.ToDisplayString(SymbolExtensions.FullNameTypeDisplayFormat));
 
                 return _names.GetValueOrDefault();
             }