(debug-on-entry-1): If function body is empty, add nil as body form.

1 files changed, 4 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 1a6ed584548..58fb3b4a1b8 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -704,6 +704,10 @@ If argument is nil or an empty string, cancel for all functions."
         ;; Skip the interactive form.
         (if (eq 'interactive (car-safe (car tail))) (setq tail (cdr tail)))
         (unless (eq flag (equal (car tail) '(debug 'debug)))
+          ;; If the function has no body, add nil as a body element.
+          (when (null tail)
+            (setq tail (list nil))
+            (nconc defn tail))
           ;; Add/remove debug statement as needed.
           (if (not flag)
               (progn (setcar tail (cadr tail))