Subject: bug#70435: 30.0.50; cc-mode: <> are sometimes not reconized as parentheses

From: Herman, Géza <[email-masked]>
Date: Wed, 17 Apr 2024 12:47:25 +0200

This is a subtle bug.  In some cases, <> template delimiters are
not recognized as delimiters, but punctuation characters.

Repro:
- put the yasnippet file (included below) into
<emacs-config-dir>/snippets/c++-mode/something
- install yasnippet
- start emacs
- M-x c++-mode
- M-x yas-minor-mode
- load snippets with "M-x yas-reload-all"
- write "ig", then press TAB to "yas-expand" the snippet
- move the cursor on the opening "<", and execute "M-x describe-char"
- notice that it will say "syntax: . which means: punctuation"
- if you edit the buffer (like add a space somewhere), and execute
describe-char again, Emacs will say "syntax: > which means: open,
matches >", so the syntax class becomes correct.

A possible explanation for this is that yasnippet edits the buffer in a
way that cc-mode doesn't notices the edit, so it has no chance to put
the correct syntax info on the inserted characters.

This is the snippet file (a simple template declaration):

--8<---------------cut here---------------start------------->8---
# -*- mode: snippet -*-
# name: something
# key: ig
# --
template <${1:typename AAA}> struct Foo;
--8<---------------cut here---------------end--------------->8---

In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, cairo version
 1.18.0) of 2024-04-12 built on okoska
Repository revision: b83d0d07bb316cd851517897a9d688d639441f90
Repository branch: my-modifications
Windowing system distributor 'The X.Org Foundation', version 11.0.12101008
System Description: Debian GNU/Linux trixie/sid

Configured using:
 'configure --with-native-compilation --without-compress-install
 --without-gconf --without-gsettings --without-dbus --with-small-ja-dic
 --with-json --with-xinput2 --with-x-toolkit=no --with-tree-sitter
 --with-cairo --with-cairo-xcb --disable-silent-rules
 'CFLAGS=-mtune=native -march=native -g3 -O3''

Configured features:
ACL CAIRO FREETYPE GIF GLIB GMP GNUTLS HARFBUZZ JPEG LCMS2 LIBOTF
LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NATIVE_COMP NOTIFY
INOTIFY OLDXMENU PDUMPER PNG RSVG SECCOMP SOUND SQLITE3 THREADS TIFF
TREE_SITTER WEBP X11 XDBE XIM XINPUT2 XPM ZLIB

Important settings:
  value of $LC_ALL: C.UTF-8
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  vertico-multiform-mode: t
  recentf-mode: t
  which-key-mode: t
  global-auto-revert-mode: t
  savehist-mode: t
  ws-butler-global-mode: t
  ws-butler-mode: t
  diff-hl-flydiff-mode: t
  global-diff-hl-mode: t
  clean-aindent-mode: t
  global-whitespace-mode: t
  marginalia-mode: t
  vertico-mode: t
  global-anzu-mode: t
  anzu-mode: t
  global-evil-matchit-mode: t
  evil-matchit-mode: t
  evil-snipe-override-mode: t
  evil-snipe-mode: t
  evil-snipe-override-local-mode: t
  evil-snipe-local-mode: t
  global-evil-surround-mode: t
  evil-surround-mode: t
  global-evil-visualstar-mode: t
  evil-visualstar-mode: t
  better-jumper-mode: t
  better-jumper-local-mode: t
  evil-leader-mode: t
  global-evil-leader-mode: t
  global-hl-todo-mode: t
  winum-mode: t
  hes-mode: t
  gcmh-mode: t
  global-page-break-lines-mode: t
  evil-mode: t
  evil-local-mode: t
  save-place-mode: t
  override-global-mode: t
  minibuffer-depth-indicate-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tab-bar-history-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  minibuffer-regexp-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  abbrev-mode: t

Load-path shadows:
/home/geza/.emacs.d/elpa/transient-20240226.2332/transient hides /usr/local/share/emacs/30.0.50/lisp/transient
~/.emacs.d/lisp/emacs-gdb/gdb-mi hides /usr/local/share/emacs/30.0.50/lisp/progmodes/gdb-mi

Features:
(shadow sort project mail-extr emacsbug message mailcap yank-media puny
evil-collection-dired dired-git-info peep-dired dired-narrow delsel
dired-filter f s dired-aux dired-x dired-subtree dired-hacks-utils
evil-collection-wdired wdired ls-lisp dired dired-loaddefs rfc822 mml
mml-sec password-cache epa derived epg rfc6068 epg-config gnus-util
time-date mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev
gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util
mail-prsvr mail-utils help-fns radix-tree mule-util cursor-sensor
evil-collection-consult consult-dir vertico-multiform consult-compile
compile evil-collection-comint comint ansi-osc ansi-color recentf
tree-widget wid-edit shut-up consult bookmark text-property-search pp
face-remap drag-stuff which-key autorevert filenotify savehist bm
evil-collection-info info ws-butler diff-hl-flydiff diff diff-hl
log-view pcvs-util vc-dir ewoc vc vc-dispatcher diff-mode
clean-aindent-mode column-enforce-mode whitespace orderless marginalia
vertico anzu evil-matchit evil-matchit-evil-setup evil-matchit-sdk
semantic/lex semantic/fw eieio eieio-core mode-local find-func
evil-exchange evil-args evil-indent-plus evil-textobj-line
evil-textobj-entire evil-textobj-column evil-textobj-anyblock evil-snipe
evil-surround evil-mc evil-mc-command-execute evil-mc-command-record
evil-mc-cursor-make evil-mc-region evil-mc-cursor-state evil-mc-undo
evil-mc-vars evil-mc-known-commands evil-mc-common avy evil-visualstar
evil-collection-simple evil-collection-replace evil-collection annalist
better-jumper pcase cl-macs evil-leader hl-todo compat hl-line
transpose-frame winum dash ov highlight-escape-sequences gcmh
page-break-lines evil evil-integration evil-maps evil-commands reveal
evil-jumps evil-command-window evil-types evil-search evil-ex
evil-macros evil-repeat evil-states evil-core evil-common thingatpt rect
evil-vars ring edmacro kmacro byte-opt saveplace bind-key easy-mmode
advice mb-depth comp cl-seq comp-cstr cl-extra help-mode warnings icons
subr-x gv cl-loaddefs cl-lib comp-run bytecomp byte-compile comp-common
rx rmc iso-transl tooltip cconv eldoc paren electric uniquify ediff-hook
vc-hooks lisp-float-type elisp-mode mwheel term/x-win x-win
term/common-win x-dnd touch-screen tool-bar dnd fontset image regexp-opt
fringe tabulated-list replace newcomment text-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 nadvice seq simple cl-generic indonesian philippine
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 emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help abbrev obarray oclosure
cl-preloaded button loaddefs theme-loaddefs faces cus-face macroexp
files window text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget keymap hashtable-print-readable backquote
threads inotify lcms2 dynamic-setting font-render-setting cairo xinput2
x multi-tty move-toolbar make-network-process native-compile emacs)

Memory information:
((conses 16 269016 316498) (symbols 48 23000 189) (strings 32 74049 29305) (string-bytes 1 3233199) (vectors 16 36374)
 (vector-slots 8 426217 134450) (floats 8 230 192) (intervals 56 2422 251) (buffers 992 12))