used_names -> get_used_names().

jedi/evaluate/compiled/mixed.py

@@ -145,7 +145,7 @@ def find_syntax_node_name(evaluator, python_object):
 
     # Doesn't always work (e.g. os.stat_result)
     try:
-        names = module.used_names[name_str]
+        names = module.get_used_names()[name_str]
     except KeyError:
         return None, None
     names = [n for n in names if n.is_definition()]