bug#18306: 24.4.50; emacs 24.4.5 hangs in c-mode with '[' character

[nick]

From: nick <nick@wordtronix.org>
To: bug-gnu-emacs@gnu.org
Subject: 24.4.50; emacs 24.4.5 hangs in c-mode with '[' character
--text follows this line--
While in c-mode writing the line: char s[]; emacs hangs without update.
Obviously not happening in this bugreport mode. :/ .
file started with : emacs -Q polak_calc.c
same behavior with: emacs polak_calc.c

This emacs was build from src on Fedora 20 from current github srcs.
Only warning was for a GTK multiple window message.

Tried: C-h k [ and received output : [ is undefined
Tried: make distclean , configure make su make install
Have not tried GDB or other debug methods while running.








In GNU Emacs 24.4.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.10.9)
 of 2014-08-20 on localhost.localdomain
Windowing system distributor `Fedora Project', version 11.0.11404000
Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GCONF GSETTINGS
NOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=ibus
  locale-coding-system: utf-8-unix

Major mode: C/l

Minor modes in effect:
  tooltip-mode: t
  electric-indent-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-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  abbrev-mode: t

Recent input:
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<menu-bar> <help-menu> <send-emacs-bug-report>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
polak_calc.c has auto save data; consider M-x recover-this-file

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message dired format-spec
rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util help-fns mail-prsvr mail-utils cc-langs cl-loaddefs cl-lib
cc-mode cc-fonts easymenu cc-guess cc-menus cc-cmds cc-styles cc-align
cc-engine cc-vars cc-defs time-date tooltip electric uniquify ediff-hook
vc-hooks lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar 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 minibuffer nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process dbusbind
gfilenotify dynamic-setting system-font-setting font-render-setting
move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:
((conses 16 107055 6788)
 (symbols 48 20371 0)
 (miscs 40 43 110)
 (strings 32 17650 4546)
 (string-bytes 1 597372)
 (vectors 16 11719)
 (vector-slots 8 412326 5631)
 (floats 8 70 262)
 (intervals 56 241 0)
 (buffers 976 12)
 (heap 1024 24438 1023))