(describe-key): No error when UNTRANSLATED is nil.

diff --git a/lisp/help.el b/lisp/help.el
index e65982623c1e8efd18d58d4918254e242ce7b368..76fc43d63ef1b7772bfec8ac8c1b9efa9e6c6584 100644 (file)
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -611,6 +611,7 @@ pass a string or a vector.
 If non-nil UNTRANSLATED is a vector of the untranslated events.
 It can also be a number in which case the untranslated events from
 the last key hit are used."
+  ;; UP-EVENT is the up-event that was discarded by reading KEY, or nil.
   (interactive "kDescribe key: \np\nU")
   (if (numberp untranslated)
       (setq untranslated (this-single-command-raw-keys)))
@@ -634,7 +635,8 @@ the last key hit are used."
          ;; Don't bother user with strings from (e.g.) the select-paste menu.
          (if (stringp (aref key (1- (length key))))
              (aset key (1- (length key)) "(any string)"))
-         (if (stringp (aref untranslated (1- (length untranslated))))
+         (if (and untranslated
+                  (stringp (aref untranslated (1- (length untranslated)))))
              (aset untranslated (1- (length untranslated))
                    "(any string)"))
          (with-output-to-temp-buffer (help-buffer)