mercurial/revset.py

--- a/mercurial/revset.py	Thu Feb 20 16:12:27 2014 -0600
+++ b/mercurial/revset.py	Fri Feb 21 13:16:17 2014 -0800
@@ -2243,9 +2243,13 @@
                 self._hiddenrevs)
 
     def __and__(self, x):
+        if isinstance(x, baseset):
+            x = x.set()
         return lazyset(self, lambda r: r in x)
 
     def __sub__(self, x):
+        if isinstance(x, baseset):
+            x = x.set()
         return lazyset(self, lambda r: r not in x)
 
     def __add__(self, x):