--- a/mercurial/revset.py	Wed Mar 12 16:40:18 2014 -0700
+++ b/mercurial/revset.py	Thu Mar 13 11:36:11 2014 -0700
@@ -2692,7 +2692,7 @@
         self._cache[x] = False
         return False
 
-class spanset(object):
+class spanset(_orderedsetmixin):
     """Duck type for baseset class which represents a range of revisions and
     can work lazily and without having all the range in memory