diff -r fbe29ca8192b Objects/dictobject.c
--- a/Objects/dictobject.c	Tue Sep 13 13:27:41 2016 +0200
+++ b/Objects/dictobject.c	Tue Sep 13 21:41:47 2016 +0800
@@ -1721,7 +1721,7 @@
     ix = (mp->ma_keys->dk_lookup)(mp, key, hash, &value_addr, &hashpos);
     if (ix == DKIX_ERROR)
         return NULL;
-    if (ix == DKIX_EMPTY) {
+    if (ix == DKIX_EMPTY || *value_addr == NULL) {
         if (deflt) {
             Py_INCREF(deflt);
             return deflt;