bug#50752: 28.0.50; easy-menu-define lowers the menu-bar key

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: stefan@marxist.se,  shuguang79@qq.com,  50752@debbugs.gnu.org
> Date: Tue, 19 Oct 2021 18:21:35 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> But perhaps that's the least bad solution?
> >
> > I think so, yes.
> 
> As for the implementation...  do you happen to know whether there are
> any locales that makes up/downcase behave differently from the "C"
> locale on ASCII characters, but does produce ASCII characters?

Not off the top of my head, no.

> I'm just wondering whether the unibyte version of down/upcase should
> just explicitly be documented to only do "C" locale stuff on unibyte
> strings?  That's easy to explain, at least, but I don't know what the
> practical repercussions would be.

This would be an unnecessary loss of functionality.  Right now, one
can arrange a case-conversion table for raw bytes, and it will work
with the current code.  We don't have to lose that, although the
utility of it is questionable.

I think we can leave the behavior with raw bytes as it is, and still
document this use case as being meant for ASCII conversions, leaving
the subtle case of raw bytes ... subtle.