bug#29812: 27.0.50; electric-quote-replace-double misbehaves in Lisp strings

[Eli Zaretskii <eliz@gnu.org>]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Sat, 30 Dec 2017 22:07:16 +0000
> Cc: 29812@debbugs.gnu.org
> 
>    emacs -Q
>    M-x electric-quote-mode RET
>    M-x set-variable RET electric-quote-replace-double RET t RET
> 
>  Type:
> 
>    "foo \"foo\""
> 
>  You get this in the buffer:
> 
>    "foo \”foo\”"
> 
>  I expected "foo \“foo\”" instead.
> 
> I think it's not completely clear what to expect here. After all, electric quote is for human-language text, which
> normally doesn't contain backslashes.

AFAIK, electric-quote-replace-double is supposed to work in comments
and strings in buffers under programming language modes, not only in
text modes.  And it works correctly for me in C modes and also in Lisp
comments, so why not in Lisp strings?

> At least in the context of Emacs Lisp strings, I'd expect "foo \"foo\"" here, i.e., ASCII quotes. The non-ASCII
> quotes don't need to be escaped, so presumably escaping means that the user intended to type an ASCII
> quote.

Typing just a quote in a Lisp string terminates the string, so I
wouldn't expect that to produce curved quotes.  And a backslash just
quotes the next character, so there's nothing wrong with having it
before curved quotes.

Anyway, if this feature is not supposed to work reliably in
programming language strings, perhaps we shouldn't try?  Having it
sometimes work and sometimes not is IMO confusing.