diff -r 54a77c556d9a Objects/typeobject.c
--- a/Objects/typeobject.c	Wed Dec 14 22:53:13 2011 -0600
+++ b/Objects/typeobject.c	Thu Dec 15 11:33:45 2011 +0000
@@ -276,6 +276,7 @@
         return -1;
     }
     Py_DECREF(tmp);
+    PyType_Modified(type);
 
     tp_name = _PyUnicode_AsString(value);
     if (tp_name == NULL)
@@ -304,6 +305,7 @@
                      type->tp_name, Py_TYPE(value)->tp_name);
         return -1;
     }
+    PyType_Modified(type);
 
     et = (PyHeapTypeObject*)type;
     Py_INCREF(value);
@@ -998,8 +1000,6 @@
         _PyObject_GC_TRACK(self);
     assert(basedealloc);
     basedealloc(self);
-
-    PyType_Modified(type);
 
     /* Can't reference self beyond this point */
     Py_DECREF(type);
@@ -2775,6 +2775,10 @@
     /* Because of type_is_gc(), the collector only calls this
        for heaptypes. */
     assert(type->tp_flags & Py_TPFLAGS_HEAPTYPE);
+
+    /* Method-cache contains borrowed refs to items in tp_dict,
+    so it must be cleared before the collector clears the dict */
+    PyType_Modified(type);
 
     /* The only field we need to clear is tp_mro, which is part of a
        hard cycle (its first element is the class itself) that won't