bug#19790: [PATCH] destructive splicing in backquote

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Sat, 14 Sep 2019 01:59:30 +0200
> Cc: Robin Templeton <robin@terpri.org>, 19790@debbugs.gnu.org,
>  Michael Heerdegen <michael_heerdegen@web.de>
> 
> > I think the conclusion to the discussion was that we do not want to
> > support the ,. operation in Emacs Lisp.
> >
> > (setq .foo 1)
> >
> > `((,.foo))
> > => (((\,\. foo)))
> >
> > So we should remove this feature completely, because that's obviously a
> > bug...
> 
> Thanks to Michael Heerdegen's pointers, I could come up with a patch.
> Would something like the attached do the job?  It simply removes this
> feature and adds a test.

Adding Stefan who was involved in the discussion back then.

I have no opinion about the change, but I think this should be in
NEWS.

Thanks.