diff --git a/lisp/smerge-mode.el b/lisp/smerge-mode.el
index cf93ad12cd9..55000391777 100644
--- a/lisp/smerge-mode.el
+++ b/lisp/smerge-mode.el
@@ -247,7 +247,7 @@ Can be nil if the style is undecided, or else:
 
 (defun smerge-ensure-match (n)
   (unless (match-end n)
-    (error (format "No `%s'" (aref smerge-match-names n)))))
+    (error "No `%s'" (aref smerge-match-names n))))
 
 (defun smerge-auto-leave ()
   (when (and smerge-auto-leave