Subject: bug#58558: 29.0.50; re-search-forward is slow in some buffers

From: Eli Zaretskii <[email-masked]>
Date: Wed, 12 Apr 2023 17:30:36 +0300

> From: Stefan Monnier <[email-masked]>
> Cc:  Ihor Radchenko <[email-masked]>, Eli Zaretskii <[email-masked]>,
>   [email-masked],  [email-masked]
> Date: Wed, 12 Apr 2023 10:06:03 -0400
> 
> > 1. emacs -Q
> > 2. M-: (require 'cc-langs) <RET>
> > 3. C-x b asd <RET>
> > 4. M-: parse-sexp-lookup-properties <RET> => t
> >
> > On Emacs 28, (4) yields nil.
> 
> I suspect that the patch below might fix the immediate problem.
> Of course, setting `parse-sexp-lookup-properties` should not have such
> a major performance impact, so maybe we should keep digging into
> the problem.

Also, that code was there in Emacs 28 as well, so how come it suddenly
has this effect now?