1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/emacs-lisp/cl-extra.el b/lisp/emacs-lisp/cl-extra.el
index c8404e0bc2d..e10844069ef 100644
--- a/lisp/emacs-lisp/cl-extra.el
+++ b/lisp/emacs-lisp/cl-extra.el
@@ -415,7 +415,8 @@ as an integer unless JUNK-ALLOWED is non-nil."
         (skip-whitespace)
         (cond ((and junk-allowed (null sum)) sum)
               (junk-allowed (* sign sum))
-              ((/= start end) (error "Not an integer string: %s" string))
+              ((or (/= start end) (null sum))
+               (error "Not an integer string: `%s'" string))
               (t (* sign sum)))))))