diff -r 5b65429721d5 -r 6261b9c549a2 mercurial/revset.py
--- a/mercurial/revset.py	Wed Sep 17 10:58:39 2014 -0700
+++ b/mercurial/revset.py	Wed Sep 17 10:58:50 2014 -0700
@@ -811,7 +811,7 @@
                 for fr in fl:
                     s.add(fl.linkrev(fr))
 
-    return subset.filter(s.__contains__)
+    return subset & s
 
 def first(repo, subset, x):
     """``first(set, [n])``