diff -r 668aba845fb2 Lib/importlib/_bootstrap.py
--- a/Lib/importlib/_bootstrap.py	Mon Jun 10 09:24:01 2013 -0700
+++ b/Lib/importlib/_bootstrap.py	Thu Jul 04 19:04:25 2013 +0200
@@ -461,7 +461,7 @@
     except (NotImplementedError, ValueError):
         source_path = bytcode_path[-1:]
 
-    return source_path if _path_isfile(source_stats) else bytecode_path
+    return source_path if _path_isfile(source_path) else bytecode_path
 
 
 def _calc_mode(path):