(derived-mode-set-keymap): Cope if old-map is nil.

diff --git a/lisp/derived.el b/lisp/derived.el
index a1cfe84..36bf142 100644 (file)
--- 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)))