diff -r 58c497d0e44d -r fa921dcd9993 mercurial/subrepo.py
--- a/mercurial/subrepo.py	Thu Feb 03 10:31:17 2011 +0100
+++ b/mercurial/subrepo.py	Wed Feb 09 13:37:21 2011 +0100
@@ -269,7 +269,7 @@
         """
         raise NotImplementedError
 
-    def merge(self, state, overwrite=False):
+    def merge(self, state):
         """merge currently-saved state with the new state."""
         raise NotImplementedError