Don't show inlay hints for component attributes (#10117)

Fixes #10088

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/InlayHints/InlayHintService.cs

@@ -5,6 +5,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.LanguageServer.Common;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.CodeAnalysis.Razor.DocumentMapping;
@@ -61,8 +62,15 @@ internal sealed class InlayHintService(IRazorDocumentMappingService documentMapp
         foreach (var hint in inlayHints)
         {
             if (hint.Position.TryGetAbsoluteIndex(csharpSourceText, null, out var absoluteIndex) &&
-                _documentMappingService.TryMapToHostDocumentPosition(csharpDocument, absoluteIndex, out Position? hostDocumentPosition, out _))
+                _documentMappingService.TryMapToHostDocumentPosition(csharpDocument, absoluteIndex, out Position? hostDocumentPosition, out var hostDocumentIndex))
             {
+                // We know this C# maps to Razor, but does it map to Razor that we like?
+                var node = await documentContext.GetSyntaxNodeAsync(hostDocumentIndex, cancellationToken).ConfigureAwait(false);
+                if (node?.FirstAncestorOrSelf<MarkupTagHelperAttributeValueSyntax>() is not null)
+                {
+                    continue;
+                }
+
                 if (hint.TextEdits is not null)
                 {
                     hint.TextEdits = _documentMappingService.GetHostDocumentEdits(csharpDocument, hint.TextEdits);

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/InlayHints/InlayHintEndpointTest.cs

@@ -41,9 +41,9 @@ private void M(string thisIsMyString)
                 """,
             toolTipMap: new Dictionary<string, string>
                 {
-                    { "int",           "struct System.Int32" },
-                    {"string",         "class System.String" },
-                    {"thisIsMyString", "(parameter) string thisIsMyStr" }
+                    { "int",            "struct System.Int32"            },
+                    { "string",         "class System.String"            },
+                    { "thisIsMyString", "(parameter) string thisIsMyStr" }
                 },
             output: """
 
@@ -62,11 +62,36 @@ private void M(string thisIsMyString)
 
                 """);
 
+    [Fact]
+    public Task InlayHints_ComponentAttributes()
+        => VerifyInlayHintsAsync(
+            input: """
+
+                <div>
+                    <InputText Value="_value" />
+                    <InputText Value="@_value" />
+                    <InputText Value="@(_value)" />
+                </div>
+
+                """,
+            toolTipMap: new Dictionary<string, string>
+                {
+                },
+            output: """
+
+                <div>
+                    <InputText Value="_value" />
+                    <InputText Value="@_value" />
+                    <InputText Value="@(_value)" />
+                </div>
+
+                """);
+
     private async Task VerifyInlayHintsAsync(string input, Dictionary<string, string> toolTipMap, string output)
     {
         TestFileMarkupParser.GetSpans(input, out input, out ImmutableDictionary<string, ImmutableArray<TextSpan>> spansDict);
-        var codeDocument = CreateCodeDocument(input);
         var razorFilePath = "C:/path/to/file.razor";
+        var codeDocument = CreateCodeDocument(input, filePath: razorFilePath);
 
         var languageServer = await CreateLanguageServerAsync(codeDocument, razorFilePath);
 

src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/LanguageServer/CSharpTestLspServer.cs

@@ -225,7 +225,17 @@ private class WorkspaceConfigurationHandler
                 values.Add(item.Section switch
                 {
                     "csharp|inlay_hints.dotnet_enable_inlay_hints_for_parameters" => "true",
+                    "csharp|inlay_hints.dotnet_enable_inlay_hints_for_literal_parameters" => "true",
+                    "csharp|inlay_hints.dotnet_enable_inlay_hints_for_indexer_parameters" => "true",
+                    "csharp|inlay_hints.dotnet_enable_inlay_hints_for_object_creation_parameters" => "true",
+                    "csharp|inlay_hints.dotnet_enable_inlay_hints_for_other_parameters" => "true",
+                    "csharp|inlay_hints.dotnet_suppress_inlay_hints_for_parameters_that_differ_only_by_suffix" => "false",
+                    "csharp|inlay_hints.dotnet_suppress_inlay_hints_for_parameters_that_match_method_intent" => "false",
+                    "csharp|inlay_hints.dotnet_suppress_inlay_hints_for_parameters_that_match_argument_name" => "false",
                     "csharp|inlay_hints.csharp_enable_inlay_hints_for_types" => "true",
+                    "csharp|inlay_hints.csharp_enable_inlay_hints_for_implicit_variable_types" => "true",
+                    "csharp|inlay_hints.csharp_enable_inlay_hints_for_lambda_parameter_types" => "true",
+                    "csharp|inlay_hints.csharp_enable_inlay_hints_for_implicit_object_creation" => "true",
                     _ => ""
                 });
             }

src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/LanguageServer/CSharpTestLspServerHelpers.cs

@@ -10,6 +10,7 @@
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Razor.Test.Common.Mef;
 using Microsoft.AspNetCore.Razor.Test.Common.Workspaces;
 using Microsoft.CodeAnalysis;
@@ -54,7 +55,10 @@ public static async Task<CSharpTestLspServer> CreateCSharpLspServerAsync(IEnumer
         var csharpFiles = files.Select(f => new CSharpFile(f.Uri, f.SourceText));
 
         var exportProvider = TestComposition.Roslyn.ExportProviderFactory.CreateExportProvider();
-        var metadataReferences = await ReferenceAssemblies.Default.ResolveAsync(language: LanguageNames.CSharp, cancellationToken);
+        var metadataReferences = (await ReferenceAssemblies.Default.ResolveAsync(language: LanguageNames.CSharp, cancellationToken))
+            // ComponentBase here comes from our ComponentShim project, not the real ASP.NET libraries. It's enough for the generated C#
+            // in tests to at least compile better.
+            .Add(MetadataReference.CreateFromFile(typeof(ComponentBase).Assembly.Location));
         var workspace = CreateCSharpTestWorkspace(csharpFiles, exportProvider, metadataReferences, razorSpanMappingService);
         var clientCapabilities = new VSInternalClientCapabilities
         {

src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/LanguageServer/LanguageServerTestBase.cs

@@ -92,6 +92,7 @@ @using BlazorApp1.Shared
                 @using System;
                 @using Microsoft.AspNetCore.Components
                 @using Microsoft.AspNetCore.Components.Authorization
+                @using Microsoft.AspNetCore.Components.Forms
                 @using Microsoft.AspNetCore.Components.Routing
                 @using Microsoft.AspNetCore.Components.Web
                 """,