--- a/contrib/mercurial.el
+++ b/contrib/mercurial.el
@@ -633,7 +633,7 @@ the file."
(modified . "m")))))))
status)))
-(defun hg-mode ()
+(defun hg-mode (&optional toggle)
"Minor mode for Mercurial distributed SCM integration.
The Mercurial mode user interface is based on that of VC mode, so if