Fix Proxy creation failure for explicit generic interface (#3034)

Fix #3029

src/NHibernate.Test/Async/StaticProxyTest/InterfaceHandling/Fixture.cs

@@ -98,6 +98,13 @@ protected override HbmMapping GetMappings()
 					rc.Property(x => x.Name);
 				});
 
+			mapper.Class<EntityWithExplicitGenericInterface>(
+				rc =>
+				{
+					rc.Table("explGenInterface");
+					rc.Id(x => x.Id);
+				});
+
 			return mapper.CompileMappingForAllExplicitlyAddedEntities();
 		}
 
@@ -177,6 +184,15 @@ public async Task ProxyInterfaceIdAccessFromDifferentInterfacesAsync()
 			}
 		}
 
+		[Test]
+		public void ProxyExplicitGenericInterfaceAsync()
+		{
+			using (var session = OpenSession())
+			{
+				Assert.That(() => session.LoadAsync<EntityWithExplicitGenericInterface>(_id), Throws.Nothing, "Failed to load EntityWithExplicitGenericInterface proxy");
+			}
+		}
+
 		private void ThrowOnIEntityNameAccess(IEntity entity)
 		{
 			Assert.That(() => entity.Name, Throws.TypeOf<ObjectNotFoundException>(), "IEntity.Name access should lead to proxy initialization");

src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Entities.cs

@@ -79,4 +79,19 @@ public class EntityWithSuperClassInterfaceLookup
 
 		public virtual IEntity EntityLookup { get; set; }
 	}
+
+	public class EntityWithExplicitGenericInterface : IGeneric
+	{
+		public virtual Guid Id { get; set; }
+
+		T[] IGeneric.GetTypes<T>()
+		{
+			return null;
+		}
+	}
+
+	public interface IGeneric
+	{
+		T[] GetTypes<T>();
+	}
 }

src/NHibernate.Test/StaticProxyTest/InterfaceHandling/Fixture.cs

@@ -87,6 +87,13 @@ protected override HbmMapping GetMappings()
 					rc.Property(x => x.Name);
 				});
 
+			mapper.Class<EntityWithExplicitGenericInterface>(
+				rc =>
+				{
+					rc.Table("explGenInterface");
+					rc.Id(x => x.Id);
+				});
+
 			return mapper.CompileMappingForAllExplicitlyAddedEntities();
 		}
 
@@ -166,6 +173,15 @@ public void ProxyInterfaceIdAccessFromDifferentInterfaces()
 			}
 		}
 
+		[Test]
+		public void ProxyExplicitGenericInterface()
+		{
+			using (var session = OpenSession())
+			{
+				Assert.That(() => session.Load<EntityWithExplicitGenericInterface>(_id), Throws.Nothing, "Failed to load EntityWithExplicitGenericInterface proxy");
+			}
+		}
+
 		private void ThrowOnIEntityNameAccess(IEntity entity)
 		{
 			Assert.That(() => entity.Name, Throws.TypeOf<ObjectNotFoundException>(), "IEntity.Name access should lead to proxy initialization");

src/NHibernate/Proxy/ProxyBuilderHelper.cs

@@ -178,8 +178,6 @@ internal static MethodBuilder GenerateMethodSignature(string name, MethodInfo me
 					CallingConventions.HasThis,
 					method.ReturnType,
 					parameters.ToArray(param => param.ParameterType));
-			if (explicitImplementation)
-				methodBuilder.SetImplementationFlags(MethodImplAttributes.Managed | MethodImplAttributes.IL);
 
 			var typeArgs = method.GetGenericArguments();
 			if (typeArgs.Length > 0)
@@ -208,6 +206,9 @@ internal static MethodBuilder GenerateMethodSignature(string name, MethodInfo me
 				}
 			}
 
+			if (explicitImplementation)
+				methodBuilder.SetImplementationFlags(MethodImplAttributes.Managed | MethodImplAttributes.IL);
+
 			return methodBuilder;
 		}