diff -r e7b8cf352614 -r 4584eec9aead mercurial/revset.py
--- a/mercurial/revset.py	Fri Oct 10 13:24:57 2014 -0700
+++ b/mercurial/revset.py	Fri Oct 10 14:22:23 2014 -0700
@@ -235,7 +235,7 @@
     if not x:
         raise error.ParseError(_("missing argument"))
     s = methods[x[0]](repo, subset, *x[1:])
-    if util.safehasattr(s, 'set'):
+    if util.safehasattr(s, 'isascending'):
         return s
     return baseset(s)