bug#67683: 30.0.50; [PATCH] Fix 'M-.' on Emacs C sources

[Eli Zaretskii]

> From: Manuel Giraud <manuel@ledu-giraud.fr>
> Cc: 67683@debbugs.gnu.org
> Date: Thu, 18 Jan 2024 20:10:41 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: Manuel Giraud <manuel@ledu-giraud.fr>
> >> Cc: 67683@debbugs.gnu.org
> >> Date: Thu, 18 Jan 2024 19:32:49 +0100
> >> 
> >> Now, I don't even know what to do to fix my current state: an
> >> explicit 'visit-tags-table' could not fix this.
> >
> > I'd suggest to step through the code in Edebug.
> 
> I'm not using Edebug but since I currently get "(void-function nil)"
> error I did a 'toggle-debug-on-error' and this error triggers when
> calling 'tags-included-tables' from 'tags-table-extend-computed-list'
> 
> What is really weird is that if I set myself into the TAGS buffer and
> evaluate (tags-included-tables), it works and returns a list of
> filenames.

And if you type "C-u M-." in the TAGS buffer, then you can type a
symbol, and Xref shows its definition allright?  IOW, does M-. work
from the TAGS buffer?