bug#51692: 29.0.50; High CPU in c++ mode. Type finder?

[Yuri D'Elia]

On Thu, Nov 11 2021, Alan Mackenzie wrote:
> Yes, there is a bug here.  CC Mode is expected to use a high amount of
> CPU time (but not 100%) for a few seconds after starting C (etc.) Mode,
> or for a few minutes after starting Emacs when there's a desktop with a
> lot of CC Mode files in it.
>
> However, with C++ files (and likely Java files, too), a problem with
> templates caused this 100% usage.

High-burst is not a problem, however I have a related question. Is it
normal that repeated C-g didn't abort?

There's nothing that seemed to work for me except waiting, which means
that with a few scrolling moves queued I just ended up killing emacs.

I didn't test if there was a difference between JIT/no-JIT versions
(should there ever be in terms of quitting behavior?)

> Then please report back to the bug list confirming that the bug is
> fixed, or telling me what's still not right.

Tested in both the small test I posted and the full source file I was
working with. Applied on master. Seems to be working perfectly now.