diff --git a/lisp/progmodes/flymake-proc.el b/lisp/progmodes/flymake-proc.el
index e2d9408e20a..62f6d1aaea2 100644
--- a/lisp/progmodes/flymake-proc.el
+++ b/lisp/progmodes/flymake-proc.el
@@ -851,7 +851,7 @@ can also be executed interactively independently of
   (interactive (list "Interrupted by user"))
   (dolist (buf (buffer-list))
     (with-current-buffer buf
-      (let (p flymake-proc--current-process)
+      (let ((p flymake-proc--current-process))
         (when (process-live-p p)
           (kill-process p)
           (process-put p 'flymake-proc--interrupted reason)