Keep complex attribute content (#9553)

* Add a test * Keep complex attribute content * Simplify form name codegen * Keep type check for mixed content * Add a test * Verify `@formname` mixed content C# diagnostics * Add integration test
2023-11-21 12:22:31 +01:00 · 2023-11-21 12:22:31 +01:00 · 630d8260fc
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentComplexAttributeContentPass.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentComplexAttributeContentPass.cs
@ -55,13 +55,11 @@ internal class ComponentComplexAttributeContentPass : ComponentIntermediateNodeP

    private static void ProcessAttribute(IntermediateNode parent, IntermediateNode node, string attributeName)
    {
-        var removeNode = false;
        var issueDiagnostic = false;

        if (node.Children is [HtmlAttributeIntermediateNode { Children.Count: > 1 }])
        {
            // This case can be hit for a 'string' attribute
-            removeNode = true;
            issueDiagnostic = true;
        }
        else if (node.Children is [CSharpExpressionIntermediateNode { Children.Count: > 1 } cSharpNode])
@ -78,7 +76,6 @@ internal class ComponentComplexAttributeContentPass : ComponentIntermediateNodeP
            }
            else
            {
-                removeNode = true;
                issueDiagnostic = true;
            }
        }
@ -86,36 +83,19 @@ internal class ComponentComplexAttributeContentPass : ComponentIntermediateNodeP
        {
            // This is the case when an attribute contains a code block @{ ... }
            // We don't support this.
-            removeNode = true;
-            issueDiagnostic = true;
-        }
-        else if (node.Children is [CSharpExpressionIntermediateNode, HtmlContentIntermediateNode { Children: [IntermediateToken { Content: "." }] }])
-        {
-            // This is the case when an attribute contains something like "@MyEnum."
-            // We simplify this to remove the "." so that tooling can provide completion on "MyEnum"
-            // in case the user is in the middle of typing
-            node.Children.RemoveAt(1);
-
-            // We still want to issue a diagnostic, even though we simplified, because ultimately
-            // we don't support this, so if the user isn't typing, we can't let this through
            issueDiagnostic = true;
        }
        else if (node.Children.Count > 1)
        {
            // This is the common case for 'mixed' content
-            removeNode = true;
            issueDiagnostic = true;
        }

        if (issueDiagnostic)
        {
-            parent.Diagnostics.Add(ComponentDiagnosticFactory.Create_UnsupportedComplexContent(
+            node.Diagnostics.Add(ComponentDiagnosticFactory.Create_UnsupportedComplexContent(
                node,
                attributeName));
        }
-        if (removeNode)
-        {
-            parent.Children.Remove(node);
-        }
    }
 }
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDesignTimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentDesignTimeNodeWriter.cs
@ -798,6 +798,12 @@ internal class ComponentDesignTimeNodeWriter : ComponentNodeWriter

    private void WriteComponentAttributeInnards(CodeRenderingContext context, ComponentAttributeIntermediateNode node, bool canTypeCheck)
    {
+        if (node.Children.Count > 1)
+        {
+            Debug.Assert(node.HasDiagnostics, "We should have reported an error for mixed content.");
+            // We render the children anyway, so tooling works.
+        }
+
        // We limit component attributes to simple cases. However there is still a lot of complexity
        // to handle here, since there are a few different cases for how an attribute might be structured.
        //
@ -807,11 +813,6 @@ internal class ComponentDesignTimeNodeWriter : ComponentNodeWriter
            // Minimized attributes always map to 'true'
            context.CodeWriter.Write("true");
        }
-        else if (node.Children.Count > 1)
-        {
-            // We don't expect this to happen, we just want to know if it can.
-            throw new InvalidOperationException("Attribute nodes should either be minimized or a single type of content." + string.Join(", ", node.Children));
-        }
        else if (node.Children.Count == 1 && node.Children[0] is HtmlContentIntermediateNode)
        {
            // We don't actually need the content at designtime, an empty string will do.
@ -1170,27 +1171,20 @@ internal class ComponentDesignTimeNodeWriter : ComponentNodeWriter

    public sealed override void WriteFormName(CodeRenderingContext context, FormNameIntermediateNode node)
    {
-        var tokens = node.FindDescendantNodes<IntermediateToken>();
-        if (tokens.Count == 0)
+        if (node.Children.Count > 1)
        {
-            return;
+            Debug.Assert(node.HasDiagnostics, "We should have reported an error for mixed content.");
        }

-        // Either all tokens should be C# or none of them.
-        if (tokens[0].IsCSharp)
+        foreach (var token in node.FindDescendantNodes<IntermediateToken>())
        {
-            context.CodeWriter.Write(ComponentsApi.RuntimeHelpers.TypeCheck);
-            context.CodeWriter.Write("<string>(");
-            foreach (var token in tokens)
+            if (token.IsCSharp)
            {
-                Debug.Assert(token.IsCSharp);
+                context.CodeWriter.Write(ComponentsApi.RuntimeHelpers.TypeCheck);
+                context.CodeWriter.Write("<string>(");
                WriteCSharpToken(context, token);
+                context.CodeWriter.WriteLine(");");
            }
-            context.CodeWriter.Write(");");
-        }
-        else
-        {
-            Debug.Assert(!tokens.Any(t => t.IsCSharp));
        }
    }

--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRenderModeLoweringPass.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRenderModeLoweringPass.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.Diagnostics;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;

 namespace Microsoft.AspNetCore.Razor.Language.Components;
@ -23,8 +22,6 @@ internal sealed class ComponentRenderModeLoweringPass : ComponentIntermediateNod
        {
            if (reference is { Node: TagHelperDirectiveAttributeIntermediateNode node, Parent: IntermediateNode parentNode } && node.TagHelper.IsRenderModeTagHelper())
            {
-                Debug.Assert(node.Diagnostics.Count == 0);
-
                if (parentNode is not ComponentIntermediateNode componentNode)
                {
                    node.Diagnostics.Add(ComponentDiagnosticFactory.CreateAttribute_ValidOnlyOnComponent(node.Source, node.OriginalAttributeName));
@ -38,6 +35,7 @@ internal sealed class ComponentRenderModeLoweringPass : ComponentIntermediateNod
                };

                var renderModeNode = new RenderModeIntermediateNode() { Source = node.Source, Children = { expression } };
+                renderModeNode.Diagnostics.AddRange(node.Diagnostics);

                if (componentNode.Component.Metadata.ContainsKey(ComponentMetadata.Component.HasRenderModeDirectiveKey))
                {
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRuntimeNodeWriter.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentRuntimeNodeWriter.cs
@ -630,16 +630,17 @@ internal class ComponentRuntimeNodeWriter : ComponentNodeWriter

    private void WriteComponentAttributeInnards(CodeRenderingContext context, ComponentAttributeIntermediateNode node, bool canTypeCheck)
    {
+        if (node.Children.Count > 1)
+        {
+            Debug.Assert(node.HasDiagnostics, "We should have reported an error for mixed content.");
+            // We render the children anyway, so tooling works.
+        }
+
        if (node.AttributeStructure == AttributeStructure.Minimized)
        {
            // Minimized attributes always map to 'true'
            context.CodeWriter.Write("true");
        }
-        else if (node.Children.Count > 1)
-        {
-            // We don't expect this to happen, we just want to know if it can.
-            throw new InvalidOperationException("Attribute nodes should either be minimized or a single type of content." + string.Join(", ", node.Children));
-        }
        else if (node.Children.Count == 1 && node.Children[0] is HtmlContentIntermediateNode htmlNode)
        {
            // This is how string attributes are lowered by default, a single HTML node with a single HTML token.
@ -944,6 +945,11 @@ internal class ComponentRuntimeNodeWriter : ComponentNodeWriter

    public sealed override void WriteFormName(CodeRenderingContext context, FormNameIntermediateNode node)
    {
+        if (node.Children.Count > 1)
+        {
+            Debug.Assert(node.HasDiagnostics, "We should have reported an error for mixed content.");
+        }
+
        // string __formName = expression;
        context.CodeWriter.Write("string ");
        context.CodeWriter.Write(_scopeStack.FormNameVarName);
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs
@ -9897,7 +9897,96 @@ namespace Test

        // Assert
        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
-        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument, verifyLinePragmas: false);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        var result = CompileToAssembly(generated, throwOnFailure: false);
+        result.Diagnostics.Verify(
+            // x:\dir\subdir\Test\TestComponent.cshtml(1,31): error CS0119: 'TestComponent.MyEnum' is a type, which is not valid in the given context
+            //                               MyEnum
+            Diagnostic(ErrorCode.ERR_BadSKunknown, "MyEnum").WithArguments("Test.TestComponent.MyEnum", "type").WithLocation(1, 31));
+        Assert.NotEmpty(generated.Diagnostics);
+    }
+
+    [IntegrationTestFact, WorkItem("https://github.com/dotnet/razor/issues/9346")]
+    public void Component_ComplexContentInAttribute_02()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse("""
+            using Microsoft.AspNetCore.Components;
+
+            namespace Test
+            {
+                public class MyComponent : ComponentBase
+                {
+                    [Parameter] public string StringProperty { get; set; }
+                }
+            }
+            """));
+
+        // Act
+        var generated = CompileToCSharp("""
+            <MyComponent StringProperty="@MyEnum+" />
+
+            @code {
+                public enum MyEnum
+                {
+                    One,
+                    Two
+                }
+            }
+            """);
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        var result = CompileToAssembly(generated, throwOnFailure: false);
+        result.Diagnostics.Verify(
+            // x:\dir\subdir\Test\TestComponent.cshtml(1,31): error CS0119: 'TestComponent.MyEnum' is a type, which is not valid in the given context
+            //                               MyEnum
+            Diagnostic(ErrorCode.ERR_BadSKunknown, "MyEnum").WithArguments("Test.TestComponent.MyEnum", "type").WithLocation(1, 31));
+        Assert.NotEmpty(generated.Diagnostics);
+    }
+
+    [IntegrationTestFact, WorkItem("https://github.com/dotnet/razor/issues/9346")]
+    public void Component_ComplexContentInAttribute_03()
+    {
+        // Arrange
+        AdditionalSyntaxTrees.Add(Parse("""
+            using Microsoft.AspNetCore.Components;
+
+            namespace Test
+            {
+                public class MyComponent : ComponentBase
+                {
+                    [Parameter] public string StringProperty { get; set; }
+                }
+            }
+            """));
+
+        // Act
+        var generated = CompileToCSharp("""
+            <MyComponent StringProperty="@x html @("string")" />
+
+            @code {
+                int x = 1;
+            }
+            """);
+
+        // Assert
+        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        var result = CompileToAssembly(generated, throwOnFailure: false);
+        result.Diagnostics.Verify(
+            // x:\dir\subdir\Test\TestComponent.cshtml(1,32): error CS1003: Syntax error, ',' expected
+            //                               x
+            Diagnostic(ErrorCode.ERR_SyntaxError, "").WithArguments(",").WithLocation(1, 32),
+            DesignTime
+            // (23,91): error CS1501: No overload for method 'TypeCheck' takes 2 arguments
+            //             __o = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.String>(
+            ? Diagnostic(ErrorCode.ERR_BadArgCount, "TypeCheck<global::System.String>").WithArguments("TypeCheck", "2").WithLocation(23, 91)
+            // (17,138): error CS1501: No overload for method 'TypeCheck' takes 2 arguments
+            //             __builder.AddComponentParameter(1, "StringProperty", global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.String>(
+            : Diagnostic(ErrorCode.ERR_BadArgCount, "TypeCheck<global::System.String>").WithArguments("TypeCheck", "2").WithLocation(17, 138));
+        Assert.NotEmpty(generated.Diagnostics);
    }

    [IntegrationTestFact]
@ -10502,7 +10591,20 @@ Time: @DateTime.Now

        // Assert
        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
-        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument, verifyLinePragmas: false);
+        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        var result = CompileToAssembly(generated, throwOnFailure: false);
+        if (DesignTime)
+        {
+            result.Diagnostics.Verify(
+                // x:\dir\subdir\Test\TestComponent.cshtml(2,74): error CS1503: Argument 1: cannot convert from 'int' to 'string'
+                //                                                                          x
+                Diagnostic(ErrorCode.ERR_BadArgType, "x").WithArguments("1", "int", "string").WithLocation(2, 74));
+        }
+        else
+        {
+            result.Diagnostics.Verify();
+        }
+        Assert.NotEmpty(generated.Diagnostics);
    }

    [IntegrationTestFact, WorkItem("https://github.com/dotnet/razor/issues/9077")]
@ -10555,6 +10657,14 @@ Time: @DateTime.Now
        // Assert
        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
+        var result = CompileToAssembly(generated, throwOnFailure: false);
+        result.Diagnostics.Verify(DesignTime
+            // (39,85): error CS7036: There is no argument given that corresponds to the required parameter 'value' of 'RuntimeHelpers.TypeCheck<T>(T)'
+            //             global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<string>();
+            ? Diagnostic(ErrorCode.ERR_NoCorrespondingArgument, "TypeCheck<string>").WithArguments("value", "Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<T>(T)").WithLocation(39, 85)
+            // (34,105): error CS7036: There is no argument given that corresponds to the required parameter 'value' of 'RuntimeHelpers.TypeCheck<T>(T)'
+            //             string __formName = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<string>();
+            : Diagnostic(ErrorCode.ERR_NoCorrespondingArgument, "TypeCheck<string>").WithArguments("value", "Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<T>(T)").WithLocation(34, 105));
    }

    [IntegrationTestFact, WorkItem("https://github.com/dotnet/razor/issues/9077")]
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.diagnostics.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.diagnostics.txt
@ -1 +1 @@
-x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'MyEnum'
+x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'MyEnum.'
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.ir.txt
@ -18,6 +18,8 @@
                    ComponentAttribute - (29:0,29 [8] x:\dir\subdir\Test\TestComponent.cshtml) - StringProperty - StringProperty - AttributeStructure.DoubleQuotes
                        CSharpExpression - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml)
                            LazyIntermediateToken - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - MyEnum
+                        HtmlContent - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html - .
                HtmlContent - (41:0,41 [4] x:\dir\subdir\Test\TestComponent.cshtml)
                    LazyIntermediateToken - (41:0,41 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\n
            CSharpCode - (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml)
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.codegen.cs
@ -0,0 +1,69 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #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)
+        {
+            __o = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.String>(
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              MyEnum
+
+#line default
+#line hidden
+#nullable disable
+            );
+            __builder.AddAttribute(-1, "ChildContent", (global::Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+            }
+            ));
+            #pragma warning disable BL0005
+            ((global::Test.MyComponent)default).
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+             StringProperty
+
+#line default
+#line hidden
+#nullable disable
+             = default;
+            #pragma warning restore BL0005
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Test.MyComponent);
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+       
+    public enum MyEnum
+    {
+        One,
+        Two
+    }
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+#pragma warning restore 1591
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.diagnostics.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.diagnostics.txt
@ -0,0 +1 @@
+x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'MyEnum+'
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.ir.txt
@ -0,0 +1,26 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        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
+                Component - (0:0,0 [41] x:\dir\subdir\Test\TestComponent.cshtml) - MyComponent
+                    ComponentAttribute - (29:0,29 [8] x:\dir\subdir\Test\TestComponent.cshtml) - StringProperty - StringProperty - AttributeStructure.DoubleQuotes
+                        CSharpExpression - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - MyEnum
+                        HtmlContent - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html - +
+                HtmlContent - (41:0,41 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (41:0,41 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\n
+            CSharpCode - (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    public enum MyEnum\n    {\n        One,\n        Two\n    }\n
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.mappings.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.mappings.txt
@ -0,0 +1,27 @@
+Source Location: (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+|MyEnum|
+Generated Location: (1056:25,30 [6] )
+|MyEnum|
+
+Source Location: (13:0,13 [14] x:\dir\subdir\Test\TestComponent.cshtml)
+|StringProperty|
+Generated Location: (1470:38,13 [14] )
+|StringProperty|
+
+Source Location: (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    public enum MyEnum
+    {
+        One,
+        Two
+    }
+|
+Generated Location: (1892:56,7 [67] )
+|
+    public enum MyEnum
+    {
+        One,
+        Two
+    }
+|
+
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.codegen.cs
@ -0,0 +1,72 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #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)
+        {
+            __o = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.String>(
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              x
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                       "string"
+
+#line default
+#line hidden
+#nullable disable
+            );
+            __builder.AddAttribute(-1, "ChildContent", (global::Microsoft.AspNetCore.Components.RenderFragment)((__builder2) => {
+            }
+            ));
+            #pragma warning disable BL0005
+            ((global::Test.MyComponent)default).
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+             StringProperty
+
+#line default
+#line hidden
+#nullable disable
+             = default;
+            #pragma warning restore BL0005
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+__o = typeof(global::Test.MyComponent);
+
+#line default
+#line hidden
+#nullable disable
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+       
+    int x = 1;
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+#pragma warning restore 1591
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.diagnostics.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.diagnostics.txt
@ -0,0 +1 @@
+x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'x html "string"'
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.ir.txt
@ -0,0 +1,29 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        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
+                Component - (0:0,0 [52] x:\dir\subdir\Test\TestComponent.cshtml) - MyComponent
+                    ComponentAttribute - (29:0,29 [19] x:\dir\subdir\Test\TestComponent.cshtml) - StringProperty - StringProperty - AttributeStructure.DoubleQuotes
+                        CSharpExpression - (30:0,30 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (30:0,30 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - x
+                        HtmlContent - (31:0,31 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (31:0,31 [5] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  html
+                            LazyIntermediateToken - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  
+                        CSharpExpression - (39:0,39 [8] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (39:0,39 [8] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - "string"
+                HtmlContent - (52:0,52 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                    LazyIntermediateToken - (52:0,52 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n\n
+            CSharpCode - (63:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (63:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    int x = 1;\n
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.mappings.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.mappings.txt
@ -0,0 +1,24 @@
+Source Location: (30:0,30 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+|x|
+Generated Location: (1056:25,30 [1] )
+|x|
+
+Source Location: (39:0,39 [8] x:\dir\subdir\Test\TestComponent.cshtml)
+|"string"|
+Generated Location: (1218:32,39 [8] )
+|"string"|
+
+Source Location: (13:0,13 [14] x:\dir\subdir\Test\TestComponent.cshtml)
+|StringProperty|
+Generated Location: (1634:45,13 [14] )
+|StringProperty|
+
+Source Location: (63:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    int x = 1;
+|
+Generated Location: (2056:63,7 [18] )
+|
+    int x = 1;
+|
+
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MixedValue/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MixedValue/TestComponent.codegen.cs
@ -32,6 +32,24 @@ using Microsoft.AspNetCore.Components.Web;
 #line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
                               () => { }

+#line default
+#line hidden
+#nullable disable
+            );
+            global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<string>(
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                                             "literal"
+
+#line default
+#line hidden
+#nullable disable
+            );
+            global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<string>(
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                                                         x
+
 #line default
 #line hidden
 #nullable disable
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MixedValue/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MixedValue/TestComponent.ir.txt
@ -26,6 +26,18 @@
                            IntermediateToken -  - CSharp - global::Microsoft.AspNetCore.Components.EventCallback.Factory.Create<global::System.EventArgs>(this, 
                            LazyIntermediateToken - (75:1,31 [9] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - () => { }
                            IntermediateToken -  - CSharp - )
+                    FormName - (97:1,53 [25] x:\dir\subdir\Test\TestComponent.cshtml)
+                        HtmlContent - (97:1,53 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (97:1,53 [5] x:\dir\subdir\Test\TestComponent.cshtml) - Html - start
+                            LazyIntermediateToken - (102:1,58 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  
+                        CSharpExpression - (105:1,61 [9] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (105:1,61 [9] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - "literal"
+                        HtmlContent - (115:1,71 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (115:1,71 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  
+                        CSharpExpression - (117:1,73 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (117:1,73 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - x
+                        HtmlContent - (118:1,74 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (118:1,74 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  end
                HtmlContent - (131:1,87 [2] x:\dir\subdir\Test\TestComponent.cshtml)
                    LazyIntermediateToken - (131:1,87 [2] x:\dir\subdir\Test\TestComponent.cshtml) - Html - \n
            CSharpCode - (140:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml)
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MixedValue/TestComponent.mappings.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MixedValue/TestComponent.mappings.txt
@ -8,11 +8,21 @@ Source Location: (75:1,31 [9] x:\dir\subdir\Test\TestComponent.cshtml)
 Generated Location: (1217:32,31 [9] )
 |() => { }|

+Source Location: (105:1,61 [9] x:\dir\subdir\Test\TestComponent.cshtml)
+|"literal"|
+Generated Location: (1529:41,61 [9] )
+|"literal"|
+
+Source Location: (117:1,73 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+|x|
+Generated Location: (1853:50,73 [1] )
+|x|
+
 Source Location: (140:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml)
 |
    int x = 1;
 |
-Generated Location: (1420:42,7 [18] )
+Generated Location: (2048:60,7 [18] )
 |
    int x = 1;
 |
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MoreElements_CSharpValue/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MoreElements_CSharpValue/TestComponent.codegen.cs
@ -44,7 +44,8 @@ using Microsoft.AspNetCore.Components.Web;
 #line default
 #line hidden
 #nullable disable
-            );__o = global::Microsoft.AspNetCore.Components.EventCallback.Factory.Create<global::System.EventArgs>(this, 
+            );
+            __o = global::Microsoft.AspNetCore.Components.EventCallback.Factory.Create<global::System.EventArgs>(this, 
 #nullable restore
 #line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
                               () => { }
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MoreElements_CSharpValue/TestComponent.mappings.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_MoreElements_CSharpValue/TestComponent.mappings.txt
@ -15,12 +15,12 @@ Generated Location: (1522:41,54 [1] )

 Source Location: (141:2,31 [9] x:\dir\subdir\Test\TestComponent.cshtml)
 |() => { }|
-Generated Location: (1799:49,31 [9] )
+Generated Location: (1813:50,31 [9] )
 |() => { }|

 Source Location: (164:2,54 [1] x:\dir\subdir\Test\TestComponent.cshtml)
 |y|
-Generated Location: (2104:58,54 [1] )
+Generated Location: (2118:59,54 [1] )
 |y|

 Source Location: (183:3,7 [44] x:\dir\subdir\Test\TestComponent.cshtml)
@ -28,7 +28,7 @@ Source Location: (183:3,7 [44] x:\dir\subdir\Test\TestComponent.cshtml)
    string x = "a";
    string y = "b";
 |
-Generated Location: (2299:68,7 [44] )
+Generated Location: (2313:69,7 [44] )
 |
    string x = "a";
    string y = "b";
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_RazorError/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_RazorError/TestComponent.codegen.cs
@ -36,6 +36,7 @@ using Microsoft.AspNetCore.Components.Web;
 #line hidden
 #nullable disable
            );
+            global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<string>();
        }
        #pragma warning restore 1998
    }
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_RazorError/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentDesignTimeCodeGenerationTest/FormName_RazorError/TestComponent.ir.txt
@ -26,3 +26,6 @@
                            IntermediateToken -  - CSharp - global::Microsoft.AspNetCore.Components.EventCallback.Factory.Create<global::System.EventArgs>(this, 
                            LazyIntermediateToken - (75:1,31 [9] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - () => { }
                            IntermediateToken -  - CSharp - )
+                    FormName - (97:1,53 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                        CSharpCode - (99:1,55 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (99:1,55 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp -  
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.diagnostics.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.diagnostics.txt
@ -1 +1 @@
-x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'MyEnum'
+x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'MyEnum.'
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute/TestComponent.ir.txt
@ -11,5 +11,7 @@
                    ComponentAttribute - (29:0,29 [8] x:\dir\subdir\Test\TestComponent.cshtml) - StringProperty - StringProperty - AttributeStructure.DoubleQuotes
                        CSharpExpression - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml)
                            LazyIntermediateToken - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - MyEnum
+                        HtmlContent - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html - .
            CSharpCode - (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml)
                LazyIntermediateToken - (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    public enum MyEnum\n    {\n        One,\n        Two\n    }\n
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.codegen.cs
@ -0,0 +1,43 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __builder.OpenComponent<global::Test.MyComponent>(0);
+            __builder.AddComponentParameter(1, "StringProperty", global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.String>(
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              MyEnum
+
+#line default
+#line hidden
+#nullable disable
+            ));
+            __builder.CloseComponent();
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+       
+    public enum MyEnum
+    {
+        One,
+        Two
+    }
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+#pragma warning restore 1591
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.diagnostics.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.diagnostics.txt
@ -0,0 +1 @@
+x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'MyEnum+'
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.ir.txt
@ -0,0 +1,17 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        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
+                Component - (0:0,0 [41] x:\dir\subdir\Test\TestComponent.cshtml) - MyComponent
+                    ComponentAttribute - (29:0,29 [8] x:\dir\subdir\Test\TestComponent.cshtml) - StringProperty - StringProperty - AttributeStructure.DoubleQuotes
+                        CSharpExpression - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (30:0,30 [6] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - MyEnum
+                        HtmlContent - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html - +
+            CSharpCode - (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    public enum MyEnum\n    {\n        One,\n        Two\n    }\n
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.mappings.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_02/TestComponent.mappings.txt
@ -0,0 +1,17 @@
+Source Location: (52:2,7 [67] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    public enum MyEnum
+    {
+        One,
+        Two
+    }
+|
+Generated Location: (1151:30,7 [67] )
+|
+    public enum MyEnum
+    {
+        One,
+        Two
+    }
+|
+
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.codegen.cs
@ -0,0 +1,46 @@
+// <auto-generated/>
+#pragma warning disable 1591
+namespace Test
+{
+    #line hidden
+    using global::System;
+    using global::System.Collections.Generic;
+    using global::System.Linq;
+    using global::System.Threading.Tasks;
+    using global::Microsoft.AspNetCore.Components;
+    public partial class TestComponent : global::Microsoft.AspNetCore.Components.ComponentBase
+    {
+        #pragma warning disable 1998
+        protected override void BuildRenderTree(global::Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder)
+        {
+            __builder.OpenComponent<global::Test.MyComponent>(0);
+            __builder.AddComponentParameter(1, "StringProperty", global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<global::System.String>(
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                              x
+
+#line default
+#line hidden
+#nullable disable
+#nullable restore
+#line 1 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                       "string"
+
+#line default
+#line hidden
+#nullable disable
+            ));
+            __builder.CloseComponent();
+        }
+        #pragma warning restore 1998
+#nullable restore
+#line 3 "x:\dir\subdir\Test\TestComponent.cshtml"
+       
+    int x = 1;
+
+#line default
+#line hidden
+#nullable disable
+    }
+}
+#pragma warning restore 1591
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.diagnostics.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.diagnostics.txt
@ -0,0 +1 @@
+x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'x html "string"'
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.ir.txt
@ -0,0 +1,20 @@
+Document - 
+    NamespaceDeclaration -  - Test
+        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
+                Component - (0:0,0 [52] x:\dir\subdir\Test\TestComponent.cshtml) - MyComponent
+                    ComponentAttribute - (29:0,29 [19] x:\dir\subdir\Test\TestComponent.cshtml) - StringProperty - StringProperty - AttributeStructure.DoubleQuotes
+                        CSharpExpression - (30:0,30 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (30:0,30 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - x
+                        HtmlContent - (31:0,31 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (31:0,31 [5] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  html
+                            LazyIntermediateToken - (36:0,36 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  
+                        CSharpExpression - (39:0,39 [8] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (39:0,39 [8] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - "string"
+            CSharpCode - (63:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml)
+                LazyIntermediateToken - (63:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    int x = 1;\n
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.mappings.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/Component_ComplexContentInAttribute_03/TestComponent.mappings.txt
@ -0,0 +1,9 @@
+Source Location: (63:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml)
+|
+    int x = 1;
+|
+Generated Location: (1315:37,7 [18] )
+|
+    int x = 1;
+|
+
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_MixedValue/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_MixedValue/TestComponent.codegen.cs
@ -31,6 +31,24 @@ using Microsoft.AspNetCore.Components.Web;
 #line hidden
 #nullable disable
            ));
+            string __formName = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<string>("start" + " " + (
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                                             "literal"
+
+#line default
+#line hidden
+#nullable disable
+            ) + " " + (
+#nullable restore
+#line 2 "x:\dir\subdir\Test\TestComponent.cshtml"
+                                                                         x
+
+#line default
+#line hidden
+#nullable disable
+            ) + " end");
+            __builder.AddNamedEvent("onsubmit", __formName);
            __builder.CloseElement();
        }
        #pragma warning restore 1998
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_MixedValue/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_MixedValue/TestComponent.ir.txt
@ -17,5 +17,17 @@
                            IntermediateToken -  - CSharp - global::Microsoft.AspNetCore.Components.EventCallback.Factory.Create<global::System.EventArgs>(this, 
                            LazyIntermediateToken - (75:1,31 [9] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - () => { }
                            IntermediateToken -  - CSharp - )
+                    FormName - (97:1,53 [25] x:\dir\subdir\Test\TestComponent.cshtml)
+                        HtmlContent - (97:1,53 [6] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (97:1,53 [5] x:\dir\subdir\Test\TestComponent.cshtml) - Html - start
+                            LazyIntermediateToken - (102:1,58 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  
+                        CSharpExpression - (105:1,61 [9] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (105:1,61 [9] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - "literal"
+                        HtmlContent - (115:1,71 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (115:1,71 [1] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  
+                        CSharpExpression - (117:1,73 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (117:1,73 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - x
+                        HtmlContent - (118:1,74 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (118:1,74 [4] x:\dir\subdir\Test\TestComponent.cshtml) - Html -  end
            CSharpCode - (140:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml)
                LazyIntermediateToken - (140:2,7 [18] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - \n    int x = 1;\n
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_MixedValue/TestComponent.mappings.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_MixedValue/TestComponent.mappings.txt
@ -2,7 +2,7 @@
 |
    int x = 1;
 |
-Generated Location: (1336:38,7 [18] )
+Generated Location: (1978:56,7 [18] )
 |
    int x = 1;
 |
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_RazorError/TestComponent.codegen.cs
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_RazorError/TestComponent.codegen.cs
@ -31,6 +31,8 @@ using Microsoft.AspNetCore.Components.Web;
 #line hidden
 #nullable disable
            ));
+            string __formName = global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<string>();
+            __builder.AddNamedEvent("onsubmit", __formName);
            __builder.CloseElement();
        }
        #pragma warning restore 1998
--- a/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_RazorError/TestComponent.ir.txt
+++ b/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/TestFiles/IntegrationTests/ComponentRuntimeCodeGenerationTest/FormName_RazorError/TestComponent.ir.txt
@ -17,3 +17,6 @@
                            IntermediateToken -  - CSharp - global::Microsoft.AspNetCore.Components.EventCallback.Factory.Create<global::System.EventArgs>(this, 
                            LazyIntermediateToken - (75:1,31 [9] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp - () => { }
                            IntermediateToken -  - CSharp - )
+                    FormName - (97:1,53 [4] x:\dir\subdir\Test\TestComponent.cshtml)
+                        CSharpCode - (99:1,55 [1] x:\dir\subdir\Test\TestComponent.cshtml)
+                            LazyIntermediateToken - (99:1,55 [1] x:\dir\subdir\Test\TestComponent.cshtml) - CSharp -  
--- a/src/Razor/test/Microsoft.VisualStudio.Razor.IntegrationTests/CompletionIntegrationTests.cs
+++ b/src/Razor/test/Microsoft.VisualStudio.Razor.IntegrationTests/CompletionIntegrationTests.cs
@ -144,6 +144,46 @@ public class CompletionIntegrationTests(ITestOutputHelper testOutputHelper) : Ab
        Assert.Null(completionSession);
    }

+    [IdeFact, WorkItem("https://github.com/dotnet/razor/issues/9346")]
+    public async Task Completion_EnumDot()
+    {
+        await TestServices.SolutionExplorer.AddFileAsync(
+            RazorProjectConstants.BlazorProjectName,
+            "Test.razor",
+            """
+            <Test Param="@MyEnum." />
+
+            @code {
+                [Parameter] public string Param { get; set; }
+
+                public enum MyEnum
+                {
+                    One
+                }
+            }
+            """,
+            open: true,
+            ControlledHangMitigatingCancellationToken);
+
+        await TestServices.Editor.WaitForComponentClassificationAsync(ControlledHangMitigatingCancellationToken);
+
+        await TestServices.Editor.PlaceCaretAsync("@MyEnum.", charsOffset: 1, ControlledHangMitigatingCancellationToken);
+        TestServices.Input.Send("O");
+
+        await CommitCompletionAndVerifyAsync("""
+            <Test Param="@MyEnum.One" />
+            
+            @code {
+                [Parameter] public string Param { get; set; }
+            
+                public enum MyEnum
+                {
+                    One
+                }
+            }
+            """);
+    }
+
    private async Task CommitCompletionAndVerifyAsync(string expected)
    {
        var textView = await TestServices.Editor.GetActiveTextViewAsync(HangMitigatingCancellationToken);
--- a/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/ErrorCode.cs
+++ b/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/ErrorCode.cs
@ -9,13 +9,17 @@ namespace Microsoft.CodeAnalysis;
 public enum ErrorCode
 {
    ERR_NameNotInContext = 103,
+    ERR_BadSKunknown = 119,
    ERR_ObjectRequired = 120,
    WRN_UnreferencedField = 169,
    ERR_SingleTypeNameNotFound = 246,
    ERR_CantInferMethTypeArgs = 411,
    WRN_UnreferencedFieldAssg = 414,
+    ERR_SyntaxError = 1003,
+    ERR_BadArgCount = 1501,
    ERR_BadArgType = 1503,
    WRN_AsyncLacksAwaits = 1998,
+    ERR_NoCorrespondingArgument = 7036,
    WRN_NullReferenceReceiver = 8602,
    WRN_UninitializedNonNullableField = 8618,
 }
				`@ -0,0 +1 @@`
				`x:\dir\subdir\Test\TestComponent.cshtml(1,30): Error RZ9986: Component attributes do not support complex content (mixed C# and markup). Attribute: 'StringProperty', text: 'MyEnum+'`