Update Regex source generator to use new GetBestTypeByMetadataName method

src/libraries/System.Text.RegularExpressions/gen/RegexGenerator.Parser.cs

@@ -4,6 +4,7 @@
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.DotnetRuntime.Extensions;
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -46,9 +47,8 @@ private static bool IsSyntaxTargetForGeneration(SyntaxNode node) =>
         // Returns null if nothing to do, Diagnostic if there's an error to report, or RegexType if the type was analyzed successfully.
         private static object? GetRegexTypeToEmit(Compilation compilation, MethodDeclarationSyntax methodSyntax, CancellationToken cancellationToken)
         {
-            // TODO: Use https://github.com/dotnet/runtime/pull/59092
-            INamedTypeSymbol? regexSymbol = compilation.GetTypeByMetadataName(RegexName);
-            INamedTypeSymbol? regexGeneratorAttributeSymbol = compilation.GetTypeByMetadataName(RegexGeneratorAttributeName);
+            INamedTypeSymbol? regexSymbol = compilation.GetBestTypeByMetadataName(RegexName);
+            INamedTypeSymbol? regexGeneratorAttributeSymbol = compilation.GetBestTypeByMetadataName(RegexGeneratorAttributeName);
             if (regexSymbol is null || regexGeneratorAttributeSymbol is null)
             {
                 // Required types aren't available

src/libraries/System.Text.RegularExpressions/gen/System.Text.RegularExpressions.Generator.csproj

@@ -20,11 +20,14 @@
     <PackageReference Include="Microsoft.DotNet.Build.Tasks.Packaging" Version="$(MicrosoftDotNetBuildTasksPackagingVersion)" PrivateAssets="all" />
   </ItemGroup>
 
-  <!-- Code included from System.Text.RegularExpressions -->
   <ItemGroup>
-    <Compile Include="..\..\Common\src\System\HexConverter.cs" Link="Production\HexConverter.cs" />
-    <Compile Include="..\..\Common\src\System\Text\ValueStringBuilder.cs" Link="Production\ValueStringBuilder.cs" />
-    <Compile Include="..\..\System.Private.CoreLib\src\System\Collections\Generic\ValueListBuilder.cs" Link="Production\ValueListBuilder.cs" />
+    <!-- Common generator support -->
+    <Compile Include="$(CommonPath)Roslyn\GetBestTypeByMetadataName.cs" Link="Common\Roslyn\GetBestTypeByMetadataName.cs" />
+
+    <!-- Code included from System.Text.RegularExpressions -->
+    <Compile Include="$(CommonPath)System\HexConverter.cs" Link="Production\HexConverter.cs" />
+    <Compile Include="$(CommonPath)System\Text\ValueStringBuilder.cs" Link="Production\ValueStringBuilder.cs" />
+    <Compile Include="$(CoreLibSharedDir)System\Collections\Generic\ValueListBuilder.cs" Link="Production\ValueListBuilder.cs" />
     <Compile Include="..\src\System\Collections\Generic\ValueListBuilder.Pop.cs" Link="Production\ValueListBuilder.Pop.cs" />
     <Compile Include="..\src\System\Text\RegularExpressions\RegexBoyerMoore.cs" Link="Production\RegexBoyerMoore.cs" />
     <Compile Include="..\src\System\Text\RegularExpressions\RegexCharClass.cs" Link="Production\RegexCharClass.cs" />

src/libraries/System.Text.RegularExpressions/tests/System.Text.RegularExpressions.Generators.Tests/RegexGeneratorParserTests.cs

@@ -475,13 +475,34 @@ public partial struct E
             ", compile: true));
         }
 
+        [Fact]
+        public async Task MultipleTypeDefinitions_DoesntBreakGeneration()
+        {
+            byte[] referencedAssembly = CreateAssemblyImage(@"
+                namespace System.Text.RegularExpressions;
+
+                [AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
+                internal sealed class RegexGeneratorAttribute : Attribute
+                {
+                    public RegexGeneratorAttribute(string pattern){}
+                }", "TestAssembly");
+
+            Assert.Empty(await RunGenerator(@"
+                using System.Text.RegularExpressions;
+                partial class C
+                {
+                    [RegexGenerator(""abc"")]
+                    private static partial Regex Valid();
+                }", compile: true, additionalRefs: new[] { MetadataReference.CreateFromImage(referencedAssembly) }));
+        }
+
         private async Task<IReadOnlyList<Diagnostic>> RunGenerator(
-            string code, bool compile = false, LanguageVersion langVersion = LanguageVersion.Preview, CancellationToken cancellationToken = default)
+            string code, bool compile = false, LanguageVersion langVersion = LanguageVersion.Preview, MetadataReference[]? additionalRefs = null, CancellationToken cancellationToken = default)
         {
             var proj = new AdhocWorkspace()
                 .AddSolution(SolutionInfo.Create(SolutionId.CreateNewId(), VersionStamp.Create()))
                 .AddProject("RegexGeneratorTest", "RegexGeneratorTest.dll", "C#")
-                .WithMetadataReferences(s_refs)
+                .WithMetadataReferences(additionalRefs is not null ? s_refs.Concat(additionalRefs) : s_refs)
                 .WithCompilationOptions(new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary)
                 .WithNullableContextOptions(NullableContextOptions.Enable))
                 .WithParseOptions(new CSharpParseOptions(langVersion))
@@ -513,10 +534,33 @@ private async Task<IReadOnlyList<Diagnostic>> RunGenerator(
             return generatorResults.Diagnostics.Concat(results.Diagnostics).Where(d => d.Severity != DiagnosticSeverity.Hidden).ToArray();
         }
 
+        private static byte[] CreateAssemblyImage(string source, string assemblyName)
+        {
+            CSharpCompilation compilation = CSharpCompilation.Create(
+                assemblyName,
+                new[] { CSharpSyntaxTree.ParseText(source, CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.Preview)) },
+                s_refs.ToArray(),
+                new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
+
+            var ms = new MemoryStream();
+            if (compilation.Emit(ms).Success)
+            {
+               return ms.ToArray();
+            }
+
+            throw new InvalidOperationException();
+        }
+
         private static readonly MetadataReference[] s_refs = CreateReferences();
 
         private static MetadataReference[] CreateReferences()
         {
+            if (PlatformDetection.IsBrowser)
+            {
+                // These tests that use Roslyn don't work well on browser wasm today
+                return new MetadataReference[0];
+            }
+
             string corelibPath = typeof(object).Assembly.Location;
             return new[]
             {

src/libraries/tests.proj

@@ -212,6 +212,10 @@
     <!-- https://github.com/dotnet/runtime/issues/58226 -->
     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.Json\tests\System.Text.Json.SourceGeneration.Unit.Tests\System.Text.Json.SourceGeneration.Roslyn3.11.Unit.Tests.csproj" />
     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.Json\tests\System.Text.Json.SourceGeneration.Unit.Tests\System.Text.Json.SourceGeneration.Roslyn4.0.Unit.Tests.csproj" />
+
+    <!-- hhttps://github.com/dotnet/runtime/issues/60048 -->
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.RegularExpressions\tests\System.Text.RegularExpressions.Tests.csproj" />
+    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.RegularExpressions\tests\System.Text.RegularExpressions.Generators.Tests\System.Text.RegularExpressions.Generators.Tests.csproj" />
   </ItemGroup>
 
   <!-- Aggressive Trimming related failures -->