xunit/xunit#3439: xUnit1051 diagnostic does not take into account [Obsolete]

Author: bradwilson

src/xunit.analyzers.tests/Analyzers/X1000/UseCancellationTokenTests.cs

@@ -188,4 +188,28 @@ public async ValueTask TestMethod() {
 
 		await Verify.VerifyAnalyzerV3(LanguageVersion.CSharp7, source);
 	}
+
+	[Fact]
+	public async Task WhenOverloadIsObsolete_DoesNotTrigger()
+	{
+		var source = /* lang=c#-test */ """
+			using System;
+			using System.Threading;
+			using System.Threading.Tasks;
+			using Xunit;
+
+			class TestClass {
+				[Fact]
+				public void TestMethod() {
+					FunctionWithOverload(42);
+				}
+
+				void FunctionWithOverload(int _) {{ }}
+				[Obsolete]
+				void FunctionWithOverload(int _1, CancellationToken _2) {{ }}
+			}
+			""";
+
+		await Verify.VerifyAnalyzerV3(source);
+	}
 }

src/xunit.analyzers/X1000/UseCancellationToken.cs

@@ -33,6 +33,9 @@ public override void AnalyzeCompilation(
 			TypeSymbolFactory.Record(context.Compilation),
 		}.WhereNotNull().ToImmutableHashSet(SymbolEqualityComparer.Default);
 
+		var attributeUsageAttribute = TypeSymbolFactory.AttributeUsageAttribute(context.Compilation);
+		var obsoleteAttribute = TypeSymbolFactory.ObsoleteAttribute(context.Compilation);
+
 		context.RegisterOperationAction(context =>
 		{
 			if (context.Operation is not IInvocationOperation invocationOperation)
@@ -82,6 +85,13 @@ public override void AnalyzeCompilation(
 				foreach (var member in invokedMethod.ContainingType.GetMembers(invokedMethod.Name))
 					if (member is IMethodSymbol method)
 					{
+						if (attributeUsageAttribute is not null && obsoleteAttribute is not null)
+						{
+							var attributes = method.GetAttributesWithInheritance(attributeUsageAttribute);
+							if (attributes.Any(a => SymbolEqualityComparer.Default.Equals(a.AttributeClass, obsoleteAttribute)))
+								continue;
+						}
+
 						var methodParameterTypes = method.Parameters.Select(p => p.Type).ToArray();
 						if (methodParameterTypes.Length != targetParameterTypes.Length)
 							continue;