--- a/mercurial/smartset.py	Mon Mar 13 08:44:57 2017 -0700
+++ b/mercurial/smartset.py	Mon Mar 13 08:53:31 2017 -0700
@@ -818,15 +818,15 @@
         # Getting rid of it would provide an about 15% speed up on this
         # iteration.
         genlist = self._genlist
-        nextrev = self._consumegen().next
-        _len = len # cache global lookup
+        nextgen = self._consumegen()
+        _len, _next = len, next # cache global lookup
         def gen():
             i = 0
             while True:
                 if i < _len(genlist):
                     yield genlist[i]
                 else:
-                    yield nextrev()
+                    yield _next(nextgen)
                 i += 1
         return gen()