bug#10634: `forward-list' scan error

[Raffaele Ricciardi]

This bug report will be sent to the Free Software Foundation,
not to your local site managers!
Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your report will be posted to the bug-gnu-emacs@gnu.org mailing list
and the gnu.emacs.bug news group, and at http://debbugs.gnu.org.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug.  If you can, give
a recipe starting from `emacs -Q':
---
Error: "forward-list: Scan error: "Containing expression ends 
prematurely", 336, 336"

How to reproduce it:
- emacs -Q
- switch to *scratch*
- in the following code:

(abc (def) (ghi) lmn)

`forward-list' fails in different positions, for instance (| is point):

(abc (|d|e|f|) (ghi) lmn)

Software: GNU Emacs 23.3.1 (i686-pc-linux-gnu, GTK+ Version 2.20.1) of 
2011-12-10 on debian

---

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
For information about debugging Emacs, please read the file
/home/lele/bin/emacs/emacs-23.3b/share/emacs/23.3/etc/DEBUG.


In GNU Emacs 23.3.1 (i686-pc-linux-gnu, GTK+ Version 2.20.1)
 of 2011-12-10 on debian
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
configured using `configure  '--prefix=/home/lele/bin/emacs/emacs-23.3b''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.utf8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
m n <delete> <delete> <delete> <delete> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <left>
<left> <left> <left> M-x M-p <return> <right> <right>
M-x M-p <return> <left> <left> <left> <left> <left>
M-x M-p <return> M-x M-p <return> <left> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <left>
<left> <left> <left> M-x M-p <return> <left> <left>
M-x M-p <return> <down-mouse-1> <mouse-1> <double-down-mouse-1>
<mouse-movement> <mouse-movement> <double-drag-mouse-1>
<help-echo> <help-echo> <help-echo> <help-echo> <tool-bar>
<copy> <help-echo> <left> <left> <left> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <left>
<left> <left> <up> <help-echo> <down-mouse-1> <mouse-movement>
<mouse-movement> <mouse-movement> <mouse-movement>
<mouse-movement> <mouse-movement> <drag-mouse-1> <delete>
<down-mouse-1> <mouse-movement> <mouse-movement> <help-echo>
<mouse-movement> <mouse-movement> <drag-mouse-1> <backspace>
<help-echo> <down-mouse-1> <mouse-1> M-x M-p <return>
<left> <left> <left> <left> <left> <left> <left> M-x
M-p <return> <left> <left> M-x M-p <return> <left>
<left> <left> <left> <left> <left> <left> M-x M-p <return>
<left> <left> <left> <left> <left> <left> <left> <left>
<left> <left> M-x M-p <return> <left> <left> <left>
<left> <left> <left> <left> <left> <left> <left> <left>
<left> <left> <left> <left> <left> M-x M-p <return>
<left> <left> <left> <left> M-x M-p <return> <right>
M-x M-p <return> <right> M-x M-p <return> <right> M-x
M-p <return> <right> M-x M-p <return> C-h C-g M-x e
m a a <backspace> c - - <backspace> <backspace> s -
v e r s i o n <return> C-h e <next> <down-mouse-1>
<mouse-movement> <mouse-movement> <drag-mouse-1> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <tool-bar>
<copy> <help-echo> C-h f f o r w a r d - l i s t <return>
<help-echo> <help-echo> <down-mouse-1> <mouse-2> <down>
<down> <down> <down> <down> <down> <down> <down> <up>
<help-echo> <menu-bar> <buffer> C-c <help-echo> <down-mouse-1>
<mouse-1> <left> i <return> <backspace> <backspace>
SPC z z z <left> <left> <left> <left> <left> <left>
M-x M-p M-p <return> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <menu-bar>
<help-menu> <send-emacs-bug-report>

Recent messages:
Type C-x 1 to delete the help window.
forward-list: Scan error: "Containing expression ends prematurely", 498, 499
forward-list: Scan error: "Containing expression ends prematurely", 503, 
504 [2 times]
Making completion list...
Quit
forward-list: Scan error: "Containing expression ends prematurely", 498, 
499 [3 times]
forward-list: Scan error: "Containing expression ends prematurely", 201, 
202 [5 times]
GNU Emacs 23.3.1 (i686-pc-linux-gnu, GTK+ Version 2.20.1) of 2011-12-10 
on debian
uncompressing lisp.el.gz...done
Note: file is write protected
forward-list: Scan error: "Containing expression ends prematurely", 205, 206

Load-path shadows:
None found.

Features:
(shadow sort mail-extr message sendmail regexp-opt ecomplete rfc822 mml
mml-sec password-cache mm-decode mm-bodies mm-encode mailcap mail-parse
rfc2231 rfc2047 rfc2045 qp ietf-drums mailabbrev nnheader gnus-util
netrc time-date mm-util mail-prsvr gmm-utils wid-edit mailheader canlock
sha1 hex-util hashcash mail-utils emacsbug jka-compr find-func help-fns
help-mode easymenu view tooltip ediff-hook vc-hooks lisp-float-type
mwheel x-win x-dnd font-setting tool-bar dnd fontset image fringe
lisp-mode register page menu-bar rfn-eshadow timer select scroll-bar
mldrag mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev loaddefs button minibuffer faces cus-face files text-properties
overlay md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process dbusbind
system-font-setting font-render-setting gtk x-toolkit x multi-tty emacs)