Allow non-dict types for the class dict when looking up names and call PyObject_GetItem() for them.

Author: Stefan Behnel

Objects/typeobject.c

@@ -2989,8 +2989,12 @@ find_name_in_mro(PyTypeObject *type, PyObject *name, int *error)
         base = PyTuple_GET_ITEM(mro, i);
         assert(PyType_Check(base));
         dict = ((PyTypeObject *)base)->tp_dict;
-        assert(dict && PyDict_Check(dict));
-        res = _PyDict_GetItem_KnownHash(dict, name, hash);
+        assert(dict);
+        if (PyDict_CheckExact(dict)) {
+            res = _PyDict_GetItem_KnownHash(dict, name, hash);
+        } else {
+            res = PyObject_GetItem(dict, name);
+        }
         if (res != NULL)
             break;
         if (PyErr_Occurred()) {