diff -r 78a3d3700233 Objects/bytesobject.c
--- a/Objects/bytesobject.c	Sun Jul 03 19:11:13 2016 -0400
+++ b/Objects/bytesobject.c	Wed Jul 06 18:38:19 2016 +0800
@@ -2624,7 +2624,7 @@
                                                                             \
         for (i = 0; i < Py_SIZE(x); i++) {                                  \
             item = GET_ITEM((x), i);                                        \
-            value = PyNumber_AsSsize_t(item, PyExc_ValueError);             \
+            value = PyNumber_AsSsize_t(item, NULL);                         \
             if (value == -1 && PyErr_Occurred())                            \
                 goto error;                                                 \
                                                                             \