objtype: Refactor dealing with native sub-objects for clarity.

py/objtype.c

@@ -135,10 +135,13 @@ STATIC void mp_obj_class_lookup(struct class_lookup_data  *lookup, const mp_obj_
                     // not type where we found a class method.
                     const mp_obj_type_t *org_type = (const mp_obj_type_t*)lookup->obj;
                     instance_convert_return_attr(NULL, org_type, elem->value, lookup->dest);
-                } else if (lookup->obj != MP_OBJ_NULL && is_native_type(type) && type != &mp_type_object /* object is not a real type */) {
-                    instance_convert_return_attr(lookup->obj->subobj[0], type, elem->value, lookup->dest);
                 } else {
-                    instance_convert_return_attr(lookup->obj, type, elem->value, lookup->dest);
+                    mp_obj_instance_t *obj = lookup->obj;
+                    if (obj != MP_OBJ_NULL && is_native_type(type) && type != &mp_type_object /* object is not a real type */) {
+                        // If we're dealing with native base class, then it applies to native sub-object
+                        obj = obj->subobj[0];
+                    }
+                    instance_convert_return_attr(obj, type, elem->value, lookup->dest);
                 }
 #if DEBUG_PRINT
                 printf("mp_obj_class_lookup: Returning: ");