@@ -51,13 +51,12 @@ public static void FinalizeObject(ManagedType self)
         {
             Runtime.PyObject_GC_Del(self.pyHandle);
             // Not necessary for decref of `tpHandle`.
-            self.gcHandle.Free();
+            self.FreeGCHandle();
         }
 
         protected void Dealloc()
         {
             FinalizeObject(this);
-            FreeGCHandle();
         }
 
         /// <summary>
 
@@ -19,6 +19,11 @@ internal abstract class ManagedType
 
         private static readonly HashSet<ManagedType> _managedObjs = new HashSet<ManagedType>();
 
+        internal void IncrRefCount()
+        {
+            Runtime.XIncref(pyHandle);
+        }
+
         internal void DecrRefCount()
         {
             Runtime.XDecref(pyHandle);
 
@@ -174,7 +174,11 @@ public ManagedType GetAttribute(string name, bool guess)
         /// </summary>
         private void StoreAttribute(string name, ManagedType ob)
         {
-            Runtime.PyDict_SetItemString(dict, name, ob.pyHandle);
+            if (Runtime.PyDict_SetItemString(dict, name, ob.pyHandle) != 0)
+            {
+                throw new PythonException();
+            }
+            ob.IncrRefCount();
             cache[name] = ob;
         }
 
 
@@ -17,14 +17,9 @@ namespace Python.Runtime
     /// </summary>
     internal class TypeManager
     {
-        private static BindingFlags tbFlags;
+        private const BindingFlags tbFlags = BindingFlags.Public | BindingFlags.Static;
         private static Dictionary<Type, IntPtr> cache;
 
-        static TypeManager()
-        {
-            tbFlags = BindingFlags.Public | BindingFlags.Static;
-        }
-
         public static void Reset()
         {
             cache = new Dictionary<Type, IntPtr>(128);
@@ -74,6 +69,7 @@ internal static IntPtr GetTypeHandle(Type type)
 
 
         /// <summary>
+        /// Return value: Borrowed reference.
         /// Get the handle of a Python type that reflects the given CLR type.
         /// The given ManagedType instance is a managed object that implements
         /// the appropriate semantics in Python for the reflected managed type.
@@ -311,7 +307,7 @@ internal static IntPtr CreateSubType(IntPtr py_name, IntPtr py_base_type, IntPtr
                 // derived class we want the python overrides in there instead if they exist.
                 IntPtr cls_dict = Marshal.ReadIntPtr(py_type, TypeOffset.tp_dict);
                 Runtime.PyDict_Update(cls_dict, py_dict);
-
+                Runtime.XIncref(py_type);
                 return py_type;
             }
             catch (Exception e)
@@ -1075,7 +1071,9 @@ private void ResetSlots()
             foreach (var offset in _slots.Keys)
             {
                 IntPtr ptr = GetDefaultSlot(offset);
+#if DEBUG
                 //DebugUtil.Print($"Set slot<{TypeOffsetHelper.GetSlotNameByOffset(offset)}> to 0x{ptr.ToString("X")} at {typeName}<0x{_type}>");
+#endif
                 Marshal.WriteIntPtr(_type, offset, ptr);
             }
Original file line number	Diff line number	Diff line change
@@ -51,13 +51,12 @@ public static void FinalizeObject(ManagedType self)
51	51	{
52	52	Runtime.PyObject_GC_Del(self.pyHandle);
53	53	// Not necessary for decref of `tpHandle`.
54		- self.gcHandle.Free();
	54	+ self.FreeGCHandle();
55	55	}
56	56
57	57	protected void Dealloc()
58	58	{
59	59	FinalizeObject(this);
60		- FreeGCHandle();
61	60	}
62	61
63	62	/// <summary>
Original file line number	Diff line number	Diff line change
@@ -174,7 +174,11 @@ public ManagedType GetAttribute(string name, bool guess)
174	174	/// </summary>
175	175	private void StoreAttribute(string name, ManagedType ob)
176	176	{
177		- Runtime.PyDict_SetItemString(dict, name, ob.pyHandle);
	177	+ if (Runtime.PyDict_SetItemString(dict, name, ob.pyHandle) != 0)
	178	+ {
	179	+ throw new PythonException();
	180	+ }
	181	+ ob.IncrRefCount();
178	182	cache[name] = ob;
179	183	}
180	184