Filter out non-public types in TextColorToGenerator assembly scanning

Directory.Build.props

@@ -243,6 +243,7 @@ https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitati
     <InternalsVisibleTo Include="CommunityToolkit.Maui.UnitTests"/>
     <InternalsVisibleTo Include="CommunityToolkit.Maui.Analyzers.UnitTests"/>
     <InternalsVisibleTo Include="CommunityToolkit.Maui.MediaElement.SourceGenerators.UnitTests"/>
+    <InternalsVisibleTo Include="CommunityToolkit.Maui.SourceGenerators.UnitTests"/>
   </ItemGroup>
 
   <PropertyGroup Condition="('$(TF_BUILD)' == 'true' OR '$(GITHUB_ACTIONS)' == 'true') and $([MSBuild]::IsOSPlatform('windows')) == 'true'">

src/CommunityToolkit.Maui.SourceGenerators.UnitTests/TextColorToGeneratorTests/TextColorToGeneratorTests.cs

@@ -0,0 +1,122 @@
+using System.IO;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using CommunityToolkit.Maui.SourceGenerators.Generators;
+using Xunit;
+
+namespace CommunityToolkit.Maui.SourceGenerators.UnitTests;
+
+public class TextColorToGeneratorTests
+{
+	[Fact]
+	public async Task Generator_DoesNotEmitCode_ForInternalMauiControlsTypes()
+	{
+		var cancellationToken = TestContext.Current.CancellationToken;
+		// Arrange: create a synthetic "Microsoft.Maui.Controls" assembly that
+		// contains both a public and an internal type implementing ITextStyle + IAnimatable.
+		const string syntheticMauiSource =
+			"""
+			namespace Microsoft.Maui
+			{
+				public interface ITextStyle
+				{
+					Microsoft.Maui.Graphics.Color TextColor { get; set; }
+				}
+			}
+
+			namespace Microsoft.Maui.Graphics
+			{
+				public class Color
+				{
+					public float Red   { get; }
+					public float Green { get; }
+					public float Blue  { get; }
+					public float Alpha { get; }
+
+					public Color WithRed(float v)   => this;
+					public Color WithGreen(float v) => this;
+					public Color WithBlue(float v)  => this;
+					public Color WithAlpha(float v) => this;
+				}
+
+				public static class Colors
+				{
+					public static Color Transparent => new();
+				}
+			}
+
+			namespace Microsoft.Maui.Controls
+			{
+				public interface IAnimatable { }
+
+				public class BindableObject
+				{
+					public void Animate(string name, Animation animation, uint rate, uint length, Easing easing) { }
+				}
+
+				public class Animation : System.Collections.IEnumerable
+				{
+					public void Add(double beginAt, double finishAt, Animation animation) { }
+					public void Commit(IAnimatable owner, string name, uint rate = 16, uint length = 250, Easing easing = null, System.Action<double, bool> finished = null) { }
+					System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() => null;
+				}
+
+				public class Easing { }
+
+				public class View : BindableObject, Microsoft.Maui.ITextStyle, IAnimatable
+				{
+					public Microsoft.Maui.Graphics.Color TextColor { get; set; }
+				}
+
+				public class PublicLabel : View { }
+				internal class InternalLabel : View { }
+			}
+			""";
+
+		var coreRef = MetadataReference.CreateFromFile(typeof(object).Assembly.Location);
+
+		var mauiCompilation = CSharpCompilation.Create(
+			"Microsoft.Maui.Controls",
+			[CSharpSyntaxTree.ParseText(syntheticMauiSource, cancellationToken: cancellationToken)],
+			[coreRef],
+			new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
+
+		using var ms = new MemoryStream();
+		var emitResult = mauiCompilation.Emit(ms, cancellationToken: cancellationToken);
+		Assert.True(emitResult.Success,
+			"Synthetic Maui assembly failed to compile: " +
+			string.Join("\n", emitResult.Diagnostics));
+
+		ms.Seek(0, SeekOrigin.Begin);
+		var mauiRef = MetadataReference.CreateFromStream(ms);
+
+		// A trivial user compilation that references the synthetic assembly.
+		const string userSource =
+			"""
+			namespace MyApp
+			{
+				public class Placeholder { }
+			}
+			""";
+
+		var userCompilation = CSharpCompilation.Create(
+			"UserAssembly",
+			[CSharpSyntaxTree.ParseText(userSource, cancellationToken: cancellationToken)],
+			[coreRef, mauiRef],
+			new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
+
+		// Act: run the generator
+		var generator = new TextColorToGenerator();
+		GeneratorDriver driver = CSharpGeneratorDriver.Create(generator);
+		driver = driver.RunGenerators(userCompilation, cancellationToken);
+
+		var runResult = driver.GetRunResult();
+		var generatedSources = runResult.GeneratedTrees
+			.Select(t => t.GetText(cancellationToken).ToString())
+			.ToList();
+
+		// Assert: code is generated for the public type, but NOT the internal one.
+		Assert.Contains(generatedSources, src => src.Contains("PublicLabel"));
+		Assert.DoesNotContain(generatedSources, src => src.Contains("InternalLabel"));
+	}
+}

src/CommunityToolkit.Maui.SourceGenerators/Generators/TextColorToGenerator.cs

@@ -249,7 +249,8 @@ static IEnumerable<INamedTypeSymbol> Deduplicate(ImmutableArray<INamedTypeSymbol
 
 	static IEnumerable<INamedTypeSymbol> GetMauiInterfaceImplementors(IAssemblySymbol mauiControlsAssemblySymbolProvider, INamedTypeSymbol iAnimatableSymbol, INamedTypeSymbol itextStyleSymbol)
 	{
-		return mauiControlsAssemblySymbolProvider.GlobalNamespace.GetNamedTypeSymbols().Where(x => x.AllInterfaces.Contains(itextStyleSymbol, SymbolEqualityComparer.Default)
+		return mauiControlsAssemblySymbolProvider.GlobalNamespace.GetNamedTypeSymbols().Where(x => x.DeclaredAccessibility == Accessibility.Public
+			&& x.AllInterfaces.Contains(itextStyleSymbol, SymbolEqualityComparer.Default)
 			&& x.AllInterfaces.Contains(iAnimatableSymbol, SymbolEqualityComparer.Default));
 	}