bug#48097: 28.0.50; C code not being correctly fontified in features/native-comp

[Alex Bennée]

This happens with a lot of C files but for a concrete reproducible
example from my development repository:

  
https://github.com/stsquad/qemu/blob/review/qtest-accel-check-v4/tests/qtest/arm-cpu-features.c

Running:

  emacs -Q tests/qtest/arm-cpu-features.c

And witness the lack of fontification from half way through assert_error
although resp_has_props seems to recover for the function prototype and
initial variable. When I run:

 M-x font-lock-debug-fontify

The fontification fixes itself although I get a bunch of errors in
Messages:

  Error during redisplay: (jit-lock-function 2666) signaled 
(wrong-type-argument number-or-marker-p nil)
  Error during redisplay: (jit-lock-function 3125) signaled 
(wrong-type-argument number-or-marker-p nil)

In GNU Emacs 28.0.50 (build 4, x86_64-pc-linux-gnu, X toolkit, cairo version 
1.16.0, Xaw3d scroll bars)
 of 2021-04-24 built on zen
Repository revision: fa65c044f2ebe666467166075c1507a8d0e1347f
Repository branch: feature/native-comp
Windowing system distributor 'The X.Org Foundation', version 11.0.12004000
System Description: Debian GNU/Linux 10 (buster)

Configured using:
 'configure --with-x-toolkit=lucid --prefix=/home/alex/src/emacs/install
 --with-modules --with-imagemagick --with-native-compilation'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ
IMAGEMAGICK JPEG JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2
M17N_FLT MODULES NATIVE_COMP NOTIFY INOTIFY PDUMPER PNG RSVG SECCOMP
SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XAW3D XDBE XIM XPM LUCID ZLIB

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

Major mode: Messages

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
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug comp comp-cstr warnings rx cl-extra
help-mode message rmc puny dired dired-loaddefs rfc822 mml mml-sec epa
derived epg epg-config gnus-util rmail rmail-loaddefs auth-source cl-seq
eieio eieio-core cl-macs eieio-loaddefs password-cache json map
text-property-search seq byte-opt gv bytecomp byte-compile cconv
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils time-date subr-x vc-git diff-mode easy-mmode vc-dispatcher
cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine
cc-vars cc-defs cl-loaddefs cl-lib iso-transl tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page tab-bar menu-bar rfn-eshadow isearch easymenu
timer select scroll-bar mouse jit-lock font-lock syntax font-core
term/tty-colors frame minibuffer 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 composite charscript charprop case-table epa-hook
jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice button
loaddefs faces cus-face macroexp files window text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote threads dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting cairo x-toolkit
x multi-tty make-network-process nativecomp emacs)

Memory information:
((conses 16 131404 9363)
 (symbols 48 10101 1)
 (strings 32 29919 2259)
 (string-bytes 1 1072854)
 (vectors 16 18858)
 (vector-slots 8 322162 14264)
 (floats 8 31 33)
 (intervals 56 2086 0)
 (buffers 992 13))

-- 
Alex Bennée
QEMU/KVM Hacker for Linaro