diff -r 4ed47a1b2d24 -r f40a57e8fda1 mercurial/revset.py
--- a/mercurial/revset.py	Fri Oct 03 01:56:57 2014 -0500
+++ b/mercurial/revset.py	Fri Oct 03 01:55:09 2014 -0500
@@ -2721,7 +2721,7 @@
         if self._ascending is not None:
             self._ascending = not self._ascending
 
-class _generatorset(object):
+class _generatorset(abstractsmartset):
     """Wrap a generator for lazy iteration
 
     Wrapper structure for generators that provides lazy membership and can