bug#13612: 24.3.50; Incorrect syntax highlighting in cc-mode

bug#13612: 24.3.50; Incorrect syntax highlighting in cc-mode

[Dima Kogan]

I'm observing incorrect highlighting of some C code I'm looking at. This
issue appears to have been around at least since emacs23.

Make a file tst.c with the following in it:



void f(void)
{
  filter_R( dt );
  filter_t( dt );

  a = b;
}



I'm observing the filter_R line being colored differently from the
filter_t line. Everything on the filter_R line is using the 'default'
face. 'filter_t' uses font-lock-type-face. 'dt' on the filter_t line
uses font-lock-variable-name-face.



In GNU Emacs 24.3.50.1 (x86_64-pc-linux-gnu, X toolkit, Xaw scroll bars)
 of 2012-12-31 on dex, modified by Debian
 (emacs-snapshot package, version 2:20121231-1)
Windowing system distributor `The X.Org Foundation', version 11.0.11204000
System Description:	Debian GNU/Linux 7.0 (wheezy)

Configured using:
 `configure --build x86_64-linux-gnu --host x86_64-linux-gnu
 --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var --infodir=/usr/share/info --mandir=/usr/share/man
 --with-pop=yes
 --enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/24.3.50/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.3.50/site-lisp:/usr/share/emacs/site-lisp
 --without-compress-info --with-crt-dir=/usr/lib/x86_64-linux-gnu/
 --with-x=yes --with-x-toolkit=lucid'

Important settings:
  value of $LC_ALL: C
  value of $LANG: C
  locale-coding-system: nil
  default enable-multibyte-characters: t

Major mode: C/l

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-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t


Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug sendmail gnus-util message cl-macs gv
format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse
rfc2231 rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mailabbrev
mail-utils gmm-utils mailheader reporter etags ring info misearch
multi-isearch pp wid-edit descr-text reposition jka-compr find-func
thai-util thai-word mule-util help-mode help-fns crm thingatpt cc-langs
cl nadvice 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
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
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 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 inotify
dynamic-setting system-font-setting font-render-setting x-toolkit x
multi-tty emacs)

bug#13612: 24.3.50; Incorrect syntax highlighting in cc-mode

[Eli Zaretskii]

> From: Dima Kogan <dima@secretsauce.net>
> Date: Sat, 02 Feb 2013 15:35:17 -0800
> 
> void f(void)
> {
>   filter_R( dt );
>   filter_t( dt );
> 
>   a = b;
> }
> 
> 
> 
> I'm observing the filter_R line being colored differently from the
> filter_t line. Everything on the filter_R line is using the 'default'
> face. 'filter_t' uses font-lock-type-face.

The "foo_t" tokens are taken as data types, AFAIK, to support size_t,
off_t, etc.

bug#13612: 24.3.50; Incorrect syntax highlighting in cc-mode

[Dima Kogan]

> On Sun, 03 Feb 2013 05:48:41 +0200
> Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: Dima Kogan <dima@secretsauce.net>
> > Date: Sat, 02 Feb 2013 15:35:17 -0800
> > 
> > void f(void)
> > {
> >   filter_R( dt );
> >   filter_t( dt );
> > 
> >   a = b;
> > }
> > 
> > I'm observing the filter_R line being colored differently from the
> > filter_t line. Everything on the filter_R line is using the
> > 'default' face. 'filter_t' uses font-lock-type-face.
> 
> The "foo_t" tokens are taken as data types, AFAIK, to support size_t,
> off_t, etc.

Ah, that makes sense now. Ideally emacs should be able to separate the two
cases, but maybe this is not significant enough to care. Thoughts? Should I
close this bug?

bug#13612: 24.3.50; Incorrect syntax highlighting in cc-mode

[Eli Zaretskii]

> Date: Mon, 4 Feb 2013 12:59:44 -0800
> From: Dima Kogan <dima@secretsauce.net>
> 
> Should I close this bug?

No, I suggest to wait for a word from the maintainer of CC Mode.

bug#13612: 24.3.50; Incorrect syntax highlighting in cc-mode

[Alan Mackenzie]

Hi, Dima!

On Mon, Feb 04, 2013 at 12:59:44PM -0800, Dima Kogan wrote:
> > On Sun, 03 Feb 2013 05:48:41 +0200
> > Eli Zaretskii <eliz@gnu.org> wrote:

> > > From: Dima Kogan <dima@secretsauce.net>
> > > Date: Sat, 02 Feb 2013 15:35:17 -0800

> > > void f(void)
> > > {
> > >   filter_R( dt );
> > >   filter_t( dt );

> > >   a = b;
> > > }

> > > I'm observing the filter_R line being colored differently from the
> > > filter_t line. Everything on the filter_R line is using the
> > > 'default' face. 'filter_t' uses font-lock-type-face.

> > The "foo_t" tokens are taken as data types, AFAIK, to support size_t,
> > off_t, etc.

> Ah, that makes sense now. Ideally emacs should be able to separate the two
> cases, ......

Do M-x customize-variable <CR> c-font-lock-extra-types, remove the entry
"\sw+_t", then reinitialise C Mode like it says.  The false fontification
should then be gone.

> ..... but maybe this is not significant enough to care. Thoughts?
> Should I close this bug?

Yes please, close it as "not a bug".  Thanks!

-- 
Alan Mackenzie (Nuremberg, Germany).