xunit/xunit#2780: Do not trigger xUnit1031 inside of ContinueWith

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

@@ -114,6 +114,23 @@ public void TestMethod() {
 
 			await Verify.VerifyAnalyzer(source);
 		}
+
+		[Fact]
+		public async void SuccessCase_GetAwaiterGetResult_InContinueWithLambda()
+		{
+			var source = @"
+using System.Threading.Tasks;
+using Xunit;
+
+public class TestClass {
+    [Fact]
+    public void TestMethod() {
+        Task.CompletedTask.ContinueWith(x => x.GetAwaiter().GetResult());
+    }
+}";
+
+			await Verify.VerifyAnalyzer(source);
+		}
 	}
 
 	public class Task_Generic
@@ -135,6 +152,23 @@ public void TestMethod() {
 			await Verify.VerifyAnalyzer(source);
 		}
 
+		[Fact]
+		public async void SuccessCase_Result_InContinueWithLambda()
+		{
+			var source = @"
+using System.Threading.Tasks;
+using Xunit;
+
+public class TestClass {
+    [Fact]
+    public void TestMethod() {
+        var _ = Task.FromResult(42).ContinueWith(x => x.Result);
+    }
+}";
+
+			await Verify.VerifyAnalyzer(source);
+		}
+
 		[Fact]
 		public async void FailureCase_GetAwaiterGetResult()
 		{
@@ -151,6 +185,23 @@ public void TestMethod() {
 
 			await Verify.VerifyAnalyzer(source);
 		}
+
+		[Fact]
+		public async void SuccessCase_GetAwaiterGetResult_InContinueWithLambda()
+		{
+			var source = @"
+using System.Threading.Tasks;
+using Xunit;
+
+public class TestClass {
+    [Fact]
+    public void TestMethod() {
+        var _ = Task.FromResult(42).ContinueWith(x => x.GetAwaiter().GetResult());
+    }
+}";
+
+			await Verify.VerifyAnalyzer(source);
+		}
 	}
 
 	public class ValueTask_NonGeneric

src/xunit.analyzers/X1000/DoNotUseBlockingTaskOperations.cs

@@ -31,6 +31,10 @@ public class DoNotUseBlockingTaskOperations : XunitDiagnosticAnalyzer
 		// These are on both Task<T> and ValueTask<T>
 		nameof(Task<int>.Result),
 	};
+	static readonly string[] continueWith = new[]
+	{
+		nameof(Task<int>.ContinueWith),
+	};
 
 	public DoNotUseBlockingTaskOperations() :
 		base(Descriptors.X1031_DoNotUseBlockingTaskOperations)
@@ -66,6 +70,9 @@ public override void AnalyzeCompilation(
 			if (!foundSymbol)
 				return;
 
+			if (WrappedInContinueWith(invocation, taskType, xunitContext))
+				return;
+
 			// Should have two child nodes: "(some other code).(target method)" and the arguments
 			var invocationChildren = invocation.Syntax.ChildNodes().ToList();
 			if (invocationChildren.Count != 2)
@@ -95,6 +102,9 @@ public override void AnalyzeCompilation(
 			if (!foundSymbol)
 				return;
 
+			if (WrappedInContinueWith(reference, taskType, xunitContext))
+				return;
+
 			// Should have two child nodes: "(some other code)" and "(property name)"
 			var propertyChildren = reference.Syntax.ChildNodes().ToList();
 			if (propertyChildren.Count != 2)
@@ -131,4 +141,24 @@ static bool FindSymbol(
 		// Only trigger when you're inside a test method
 		return operation.IsInTestMethod(xunitContext);
 	}
+
+	static bool WrappedInContinueWith(
+		IOperation? operation,
+		INamedTypeSymbol? taskType,
+		XunitContext xunitContext)
+	{
+		if (taskType is null)
+			return false;
+
+		for (; operation != null; operation = operation.Parent)
+		{
+			if (operation is not IInvocationOperation invocation)
+				continue;
+
+			if (FindSymbol(invocation.TargetMethod, invocation, taskType, continueWith, xunitContext))
+				return true;
+		}
+
+		return false;
+	}
 }