diff -r a64a3da996ed Python/ceval.c
--- a/Python/ceval.c	Sun May 05 11:35:15 2013 -0500
+++ b/Python/ceval.c	Tue May 07 08:47:02 2013 -0700
@@ -3517,8 +3517,10 @@
         int arg;
         /* Possibly account for the cell variable being an argument. */
         if (co->co_cell2arg != NULL &&
-            (arg = co->co_cell2arg[i]) != CO_CELL_NOT_AN_ARG)
+            (arg = co->co_cell2arg[i]) != CO_CELL_NOT_AN_ARG) {
             c = PyCell_New(GETLOCAL(arg));
+	    SETLOCAL(arg, NULL);
+	}
         else
             c = PyCell_New(NULL);
         if (c == NULL)