(shell-filter-ctrl-a-ctrl-b): Check if `comint-last-output-start' is

a marker by using `markerp' and check if it has a position by using
`marker-position', and use this position for `goto-char'.

1 files changed, 3 insertions, 1 deletions

diff --git a/lisp/shell.el b/lisp/shell.el
index 6a145ae1569..d4791821b5b 100644
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -483,7 +483,9 @@ This function can be put on `comint-output-filter-functions'.
 The argument STRING is ignored."
   (let ((pmark (process-mark (get-buffer-process (current-buffer)))))
     (save-excursion
-      (goto-char (or comint-last-output-start (point-min)))
+      (goto-char (or (and (markerp comint-last-output-start)
+                          (marker-position comint-last-output-start))
+                     (point-min)))
       (while (re-search-forward "[\C-a\C-b]" pmark t)
         (replace-match "")))))