diff --git a/lisp/progmodes/elisp-mode.el b/lisp/progmodes/elisp-mode.el
index 2617a6e4cce..f39ecf9b7bc 100644
--- a/lisp/progmodes/elisp-mode.el
+++ b/lisp/progmodes/elisp-mode.el
@@ -264,9 +264,9 @@ Blank lines separate paragraphs.  Semicolons start comments.
   (unless
       (let* ((bfname (buffer-file-name))
              (fname (and (stringp bfname) (file-name-nondirectory bfname))))
-        (or (not (stringp fname))
-            (string-match "\\`\\.#" fname)
-            (string-equal dir-locals-file fname)))
+        (and (stringp fname)
+             (or (string-match "\\`\\.#" fname)
+                 (string-equal dir-locals-file fname))))
     (add-hook 'flymake-diagnostic-functions #'elisp-flymake-checkdoc nil t)
     (add-hook 'flymake-diagnostic-functions
               #'elisp-flymake-byte-compile nil t)))