--- a/mercurial/revset.py	Fri Apr 25 17:53:58 2014 -0700
+++ b/mercurial/revset.py	Fri Apr 25 14:51:24 2014 -0700
@@ -2342,7 +2342,8 @@
     def __contains__(self, x):
         c = self._cache
         if x not in c:
-            c[x] = x in self._subset and self._condition(x)
+            v = c[x] = x in self._subset and self._condition(x)
+            return v
         return c[x]
 
     def __iter__(self):