bug#60953: The :match predicate with large regexp in tree-sitter font-lock seems inefficient

[Eli Zaretskii]

> Date: Thu, 2 Feb 2023 19:03:52 +0200
> Cc: casouri@gmail.com, 60953@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> 
> > One gotcha: fast_looking_at returns the length of the match, whereas
> > search_buffer returns the buffer position where it matched.  Shouldn't
> > this need a different handling of the return value?
> 
> Probably not: we just need to know whether it matched or not. And when 
> it did not, it returns 0, right? So the same check should work.

Which check?

If the search fails, search_buffer returns a non-positive integer, not
zero.