diff --git a/lisp/vc/vc.el b/lisp/vc/vc.el
index 401b39145c8..0d29c80d026 100644
--- a/lisp/vc/vc.el
+++ b/lisp/vc/vc.el
@@ -3032,7 +3032,7 @@ to provide the `find-revision' operation instead."
   "Let BACKEND receive FILE from another version control system."
   (vc-call-backend backend 'register (list file) rev ""))
 
-(defun vc-default-update-on-retrieve-tag ()
+(defun vc-default-update-on-retrieve-tag (_backend)
   "Prompt for update buffers on `vc-retrieve-tag'."
   t)