pythonnet · filmor · Nov 2, 2022 · Nov 2, 2022 · Nov 2, 2022
diff --git a/src/runtime/Types/ClassDerived.cs b/src/runtime/Types/ClassDerived.cs
@@ -436,6 +436,7 @@ private static void AddVirtualMethod(MethodInfo method, Type baseType, TypeBuild
             il.Emit(OpCodes.Ldloc_0);
 
             il.Emit(OpCodes.Ldtoken, method);
+            il.Emit(OpCodes.Ldtoken, method.DeclaringType);
 #pragma warning disable CS0618 // PythonDerivedType is for internal use only
             if (method.ReturnType == typeof(void))
             {
@@ -505,6 +506,7 @@ private static void AddPythonMethod(string methodName, PyObject func, TypeBuilde
 
             il.DeclareLocal(typeof(object[]));
             il.DeclareLocal(typeof(RuntimeMethodHandle));
+            il.DeclareLocal(typeof(RuntimeTypeHandle));
 
             // this
             il.Emit(OpCodes.Ldarg_0);
@@ -546,6 +548,11 @@ private static void AddPythonMethod(string methodName, PyObject func, TypeBuilde
             il.Emit(OpCodes.Ldloca_S, 1);
             il.Emit(OpCodes.Initobj, typeof(RuntimeMethodHandle));
             il.Emit(OpCodes.Ldloc_1);
+
+            // type handle is also not required
+            il.Emit(OpCodes.Ldloca_S, 2);
+            il.Emit(OpCodes.Initobj, typeof(RuntimeTypeHandle));
+            il.Emit(OpCodes.Ldloc_2);
 #pragma warning disable CS0618 // PythonDerivedType is for internal use only
 
             // invoke the method
@@ -698,7 +705,7 @@ public class PythonDerivedType
         /// class) it calls it, otherwise it calls the base method.
         /// </summary>
         public static T? InvokeMethod<T>(IPythonDerivedType obj, string methodName, string origMethodName,
-            object[] args, RuntimeMethodHandle methodHandle)
+            object[] args, RuntimeMethodHandle methodHandle, RuntimeTypeHandle declaringTypeHandle)
         {
             var self = GetPyObj(obj);
 
@@ -724,7 +731,10 @@ public class PythonDerivedType
                             }
 
                             PyObject py_result = method.Invoke(pyargs);
-                            PyTuple? result_tuple = MarshalByRefsBack(args, methodHandle, py_result, outsOffset: 1);
+                            var clrMethod = methodHandle != default
+                                ? MethodBase.GetMethodFromHandle(methodHandle, declaringTypeHandle)
+                                : null;
+                            PyTuple? result_tuple = MarshalByRefsBack(args, clrMethod, py_result, outsOffset: 1);
                             return result_tuple is not null
                                 ? result_tuple[0].As<T>()
                                 : py_result.As<T>();
@@ -754,7 +764,7 @@ public class PythonDerivedType
         }
 
         public static void InvokeMethodVoid(IPythonDerivedType obj, string methodName, string origMethodName,
-            object?[] args, RuntimeMethodHandle methodHandle)
+            object?[] args, RuntimeMethodHandle methodHandle, RuntimeTypeHandle declaringTypeHandle)
         {
             var self = GetPyObj(obj);
             if (null != self.Ref)
@@ -779,7 +789,10 @@ public static void InvokeMethodVoid(IPythonDerivedType obj, string methodName, s
                             }
 
                             PyObject py_result = method.Invoke(pyargs);
-                            MarshalByRefsBack(args, methodHandle, py_result, outsOffset: 0);
+                            var clrMethod = methodHandle != default
+                                ? MethodBase.GetMethodFromHandle(methodHandle, declaringTypeHandle)
+                                : null;
+                            MarshalByRefsBack(args, clrMethod, py_result, outsOffset: 0);
                             return;
                         }
                     }
@@ -811,12 +824,11 @@ public static void InvokeMethodVoid(IPythonDerivedType obj, string methodName, s
         /// as a tuple of new values for those arguments, and updates corresponding
         /// elements of <paramref name="args"/> array.
         /// </summary>
-        private static PyTuple? MarshalByRefsBack(object?[] args, RuntimeMethodHandle methodHandle, PyObject pyResult, int outsOffset)
+        private static PyTuple? MarshalByRefsBack(object?[] args, MethodBase? method, PyObject pyResult, int outsOffset)
         {
-            if (methodHandle == default) return null;
+            if (method is null) return null;
 
-            var originalMethod = MethodBase.GetMethodFromHandle(methodHandle);
-            var parameters = originalMethod.GetParameters();
+            var parameters = method.GetParameters();
             PyTuple? outs = null;
             int byrefIndex = 0;
             for (int i = 0; i < parameters.Length; ++i)

diff --git a/src/testing/interfacetest.cs b/src/testing/interfacetest.cs
@@ -79,7 +79,7 @@ private interface IPrivate
         {
         }
     }
-    
+
     public interface IOutArg
     {
         string MyMethod_Out(string name, out int index);
@@ -93,4 +93,25 @@ public static int CallMyMethod_Out(IOutArg myInterface)
             return index;
         }
     }
+
+    public interface IGenericInterface<T>
+    {
+        public T Get(T x);
+    }
+
+    public class SpecificInterfaceUser
+    {
+        public SpecificInterfaceUser(IGenericInterface<int> some, int x)
+        {
+            some.Get(x);
+        }
+    }
+
+    public class GenericInterfaceUser<T>
+    {
+        public GenericInterfaceUser(IGenericInterface<T> some, T x)
+        {
+            some.Get(x);
+        }
+    }
 }
diff --git a/tests/test_subclass.py b/tests/test_subclass.py
@@ -9,7 +9,7 @@
 import System
 import pytest
 from Python.Test import (IInterfaceTest, SubClassTest, EventArgsTest,
-                         FunctionsTest)
+                         FunctionsTest, IGenericInterface)
 from System.Collections.Generic import List
 
 
@@ -29,6 +29,17 @@ def bar(self, x, i):
     return InterfaceTestClass
 
 
+def interface_generic_class_fixture(subnamespace):
+
+    class GenericInterfaceImpl(IGenericInterface[int]):
+        __namespace__ = "Python.Test." + subnamespace
+
+        def Get(self, x):
+            return x
+
+    return GenericInterfaceImpl
+
+
 def derived_class_fixture(subnamespace):
     """Delay creation of class until test starts."""
 
@@ -306,3 +317,13 @@ class Derived(BaseClass):
 
     import gc
     gc.collect()
+
+def test_generic_interface():
+    from System import Int32
+    from Python.Test import GenericInterfaceUser, SpecificInterfaceUser
+
+    GenericInterfaceImpl = interface_generic_class_fixture(test_generic_interface.__name__)
+
+    obj = GenericInterfaceImpl()
+    SpecificInterfaceUser(obj, Int32(0))
+    GenericInterfaceUser[Int32](obj, Int32(0))