Merge pull request #657 from stakx/bug/method-invocation-target

Fix `ArgumentException`: "Could not find method overriding method" with overridden class method having generic by-ref parameter

CHANGELOG.md

@@ -6,6 +6,9 @@ Enhancements:
 - Two new generic method overloads `proxyGenerator.CreateClassProxy<TClass>([options], constructorArguments, interceptors)` (@backstromjoel, #636)
 - Allow specifying which attributes should always be copied to proxy class by adding attribute type to `AttributesToAlwaysReplicate`. Previously only non-inherited, with `Inherited=false`, attributes were copied. (@shoaibshakeel381, #633)
 
+Bugfixes:
+- `ArgumentException`: "Could not find method overriding method" with overridden class method having generic by-ref parameter (@stakx, #657)
+
 ## 5.1.1 (2022-12-30)
 
 Bugfixes:

src/Castle.Core.Tests/DynamicProxy.Tests/OutRefParamsTestCase.cs

@@ -92,6 +92,17 @@ public virtual void MyMethodWithStruct(ref MyStruct s)
 			}
 		}
 
+		public class Factory
+		{
+			public virtual void Create<T>(out T result) => result = default(T);
+		}
+
+		public class DerivedFactory : Factory
+		{
+			public override void Create<T>(out T result) => result = default(T);
+
+		}
+
 		[Test]
 		public void CanAffectValueOfOutParameter()
 		{
@@ -353,5 +364,13 @@ public void Exception_during_method_out_ref_arguments_set_interface_proxy_with_t
 			Assert.AreEqual(23, param1);
 			Assert.AreEqual("23", param2);
 		}
+
+		[Test]
+		public void Can_query_MethodInvocationTarget_for_overridden_class_method_having_a_generic_by_ref_parameter()
+		{
+			var interceptor = new WithCallbackInterceptor(invocation => _ = invocation.MethodInvocationTarget);
+			var proxy = generator.CreateClassProxy<DerivedFactory>(interceptor);
+			proxy.Create<object>(out _);
+		}
 	}
-}
+}

src/Castle.Core/DynamicProxy/Generators/MethodSignatureComparer.cs

@@ -103,6 +103,17 @@ public bool EqualReturnTypes(MethodInfo x, MethodInfo y)
 
 		private bool EqualSignatureTypes(Type x, Type y)
 		{
+			if (x.IsByRef != y.IsByRef)
+			{
+				return false;
+			}
+			else if (x.IsByRef)
+			{
+				// If `x` or `y` are by-ref generic types or type parameters (think `ref T` or `out T`),
+				// the tests below would report false, so we need to erase by-ref-ness first:
+				return EqualSignatureTypes(x.GetElementType(), y.GetElementType());
+			}
+
 			if (x.IsGenericParameter != y.IsGenericParameter)
 			{
 				return false;