(read-number): Check whether `default' is nil.

1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/subr.el b/lisp/subr.el
index 39a9caa3106..81f774bdc68 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -1329,7 +1329,8 @@ Optional DEFAULT is a default password to use instead of empty input."
     (while
         (progn
           (let ((str (read-from-minibuffer prompt nil nil nil nil
-                                           (number-to-string default))))
+                                           (and default
+                                                (number-to-string default)))))
             (setq n (cond
                      ((zerop (length str)) default)
                      ((stringp str) (read str)))))