--- a/mercurial/revset.py	Fri Sep 19 07:23:10 2014 +0530
+++ b/mercurial/revset.py	Tue Sep 16 22:55:49 2014 -0700
@@ -78,7 +78,7 @@
     if not roots:
         return baseset([])
     parentrevs = repo.changelog.parentrevs
-    visit = baseset(heads)
+    visit = list(heads)
     reachable = set()
     seen = {}
     minroot = min(roots)