--- a/mercurial/revset.py	Mon Apr 28 17:25:36 2014 -0700
+++ b/mercurial/revset.py	Mon Apr 28 16:28:52 2014 -0700
@@ -2783,8 +2783,8 @@
             for r in iterrange:
                 yield r
 
-    def __contains__(self, x):
-        return self._contained(x) and not (self._hiddenrevs and rev in
+    def __contains__(self, rev):
+        return self._contained(rev) and not (self._hiddenrevs and rev in
                 self._hiddenrevs)
 
     def __nonzero__(self):