1 files changed, 3 insertions, 2 deletions

diff --git a/lisp/derived.el b/lisp/derived.el
index a1cfe8485f8..36bf1428125 100644
--- a/lisp/derived.el
+++ b/lisp/derived.el
@@ -255,8 +255,9 @@ which more-or-less shadow
   (let* ((map-name (derived-mode-map-name mode))
          (new-map (eval map-name))
          (old-map (current-local-map)))
-    (if (get map-name 'derived-mode-unmerged)
-        (derived-mode-merge-keymaps old-map new-map))
+    (and old-map
+         (get map-name 'derived-mode-unmerged)
+         (derived-mode-merge-keymaps old-map new-map))
     (put map-name 'derived-mode-unmerged nil)
     (use-local-map new-map)))