Fix 'C-d' on the first line in Rmail summary buffer

* lisp/mail/rmailsum.el (rmail-summary-delete-forward): Fix
deleting backward past the beginning of the summary buffer.
(Bug#46325)

1 files changed, 5 insertions, 4 deletions

diff --git a/lisp/mail/rmailsum.el b/lisp/mail/rmailsum.el
index 7f99ecdcf2c..f53e6e768f8 100644
--- a/lisp/mail/rmailsum.el
+++ b/lisp/mail/rmailsum.el
@@ -930,10 +930,11 @@ a negative argument means to delete and move backward."
   (unless (numberp count) (setq count 1))
   (let (del-msg
         (backward (< count 0)))
-    (while (and (/= count 0)
-                ;; Don't waste time if we are at the beginning
-                ;; and trying to go backward.
-                (not (and backward (bobp))))
+    (while (/= count 0)
+      ;; Don't waste time counting down without doing anything if we
+      ;; are at the beginning and trying to go backward.
+      (if (and backward (bobp))
+          (setq count -1))
       (rmail-summary-goto-msg)
       (with-current-buffer rmail-buffer
         (setq del-msg rmail-current-message)