diff -r a14642bdf364 -r acabbc5ccd24 mercurial/match.py
--- a/mercurial/match.py	Sat Sep 30 07:44:34 2017 -0400
+++ b/mercurial/match.py	Sat Sep 30 07:44:45 2017 -0400
@@ -250,7 +250,6 @@
     def bad(self, f, msg):
         '''Callback from dirstate.walk for each explicit file that can't be
         found/accessed, with an error message.'''
-        pass
 
     # If an explicitdir is set, it will be called when an explicitly listed
     # directory is visited.