Add failing tests for covariant return types involving a variant generic interface

Author: stakx

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

@@ -52,6 +52,7 @@ public void Reflection_returns_methods_from_a_derived_class_before_methods_from_
 		[TestCase(typeof(DerivedClassWithStringInsteadOfObject))]
 		[TestCase(typeof(DerivedClassWithStringInsteadOfInterface))]
 		[TestCase(typeof(DerivedClassWithStringInsteadOfGenericArg))]
+		[TestCase(typeof(BottleOfWater))]
 		public void Can_proxy_type_having_method_with_covariant_return(Type classToProxy)
 		{
 			_ = generator.CreateClassProxy(classToProxy, new StandardInterceptor());
@@ -62,6 +63,7 @@ public void Can_proxy_type_having_method_with_covariant_return(Type classToProxy
 		[TestCase(typeof(DerivedClassWithStringInsteadOfObject), typeof(string))]
 		[TestCase(typeof(DerivedClassWithStringInsteadOfInterface), typeof(string))]
 		[TestCase(typeof(DerivedClassWithStringInsteadOfGenericArg), typeof(string))]
+		[TestCase(typeof(BottleOfWater), typeof(Glass<Water>))]
 		public void Proxied_method_has_correct_return_type(Type classToProxy, Type expectedMethodReturnType)
 		{
 			var proxy = generator.CreateClassProxy(classToProxy, new StandardInterceptor());
@@ -116,6 +118,22 @@ public class DerivedClassWithStringInsteadOfGenericArg : BaseClassWithGenericArg
 		{
 			public override string Method() => nameof(DerivedClassWithStringInsteadOfGenericArg);
 		}
+
+		public interface Glass<out T> { }
+
+		public class Liquid { }
+
+		public class Water : Liquid { }
+
+		public class BottleOfLiquid
+		{
+			public virtual Glass<Liquid> Method() => default(Glass<Liquid>);
+		}
+
+		public class BottleOfWater : BottleOfLiquid
+		{
+			public override Glass<Water> Method() => default(Glass<Water>);
+		}
 	}
 }