diff -r d9fb88c045a0 -r e5f166961123 mercurial/revset.py
--- a/mercurial/revset.py	Mon May 04 10:38:45 2015 -0700
+++ b/mercurial/revset.py	Sat Oct 11 01:17:40 2014 -0700
@@ -1684,7 +1684,7 @@
     Changesets in set with no parent changeset in set.
     """
     s = getset(repo, fullreposet(repo), x)
-    subset = baseset([r for r in s if r in subset])
+    subset = subset & s# baseset([r for r in s if r in subset])
     cs = _children(repo, subset, s)
     return subset - cs