--- a/Python/ceval.c	Tue May 14 11:35:16 2013 -0400
+++ b/Python/ceval.c	Tue May 14 22:31:26 2013 -0500
@@ -3403,10 +3403,14 @@
         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));
-        else
+            /* Clear the local copy. */
+            SETLOCAL(arg, NULL);
+        }
+        else {
             c = PyCell_New(NULL);
+        }
         if (c == NULL)
             goto fail;
         SETLOCAL(co->co_nlocals + i, c);