bug#23308: 25.0.92; angle brackects in #include breaks syntax-ppss (c-mode)

[Mohammed Sadik]

In c-mode (may be in other modes too), lines like #include <stdio.h>
sometimes break (nth 0 (syntax-ppss)), the depth of brackets. This
happens because angle brackets ('<' and '>') in #include lines are
considered to be brackets (which is true) in emacs 25.0.92, but not
in emacs 24.5, where syntax-ppss doesn't break.

How to reproduce:

open a new c file: emacs -Q test.c

Type the following in the file (where | is the point):

     #include <>

     int
     main (void)
     {
       |
     }

Now move between the angle brackets (| is the point):
    #include <|>

    ...

Now type some header names:

    #include <stdio.h|>

    ...

Now check the first value of (syntax-ppss). It is zero.

Now move to some other point (don't press RET). Check the value of
syntax-ppss.
The value is negative when outside of any paren,



In GNU Emacs 25.0.92.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)
 of 2016-04-13 built on fedora.localdomain
Windowing system distributor 'Fedora Project', version 11.0.11800000
Configured features:
XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS NOTIFY ACL LIBSELINUX GNUTLS
LIBXML2 FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LC_MONETARY: en_IN.UTF-8
  value of $LC_NUMERIC: en_IN.UTF-8
  value of $LC_TIME: en_IN.UTF-8
  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
  global-eldoc-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
  transient-mark-mode: t
  abbrev-mode: t

Recent messages:
Making completion list... [2 times]
Quit
(0 nil 27 nil nil nil 0 nil nil nil)
(1 34 47 nil nil nil 0 nil nil (34)) [2 times]
(1 34 42 nil nil nil 0 nil nil (34))
(1 34 47 nil nil nil 0 nil nil (34)) [2 times]
(0 nil 18 nil nil nil 0 nil nil nil)
(1 10 11 nil nil nil 0 nil nil (10))
Quit
Making completion list...

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message dired format-spec rfc822 mml
mml-sec epg epg-config gnus-util 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 kmacro
cl-extra help-mode cc-mode cc-fonts easymenu cc-guess cc-menus cc-cmds
cc-styles cc-align cc-engine cc-vars cc-defs cl-loaddefs pcase cl-lib
time-date mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel x-win term/common-win x-dnd tool-bar dnd fontset
image regexp-opt fringe tabulated-list newcomment elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
mouse jit-lock font-lock syntax facemenu font-core frame cl-generic cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese charscript case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer cl-preloaded 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 dbusbind inotify dynamic-setting
system-font-setting font-render-setting move-toolbar gtk x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 107267 13276)
 (symbols 48 21692 0)
 (miscs 40 83 207)
 (strings 32 19882 3213)
 (string-bytes 1 682011)
 (vectors 16 14908)
 (vector-slots 8 453358 9139)
 (floats 8 170 204)
 (intervals 56 250 42)
 (buffers 976 13)
 (heap 1024 39952 1257))