bug#55205: 28.1.50; completion--replace illegally mutates completion candidates

[Dmitry Gutov]

On 01.05.2022 23:54, Lars Ingebrigtsen wrote:
> Yes, of course I can do that.  But I didn't want to that (because it's
> doubleplusungood), so I had to copy half of minibuffer.el into my
> project and alter it.

IDK. When thinking about the properties-equality problem, I also ended 
up with this approach as the most failsafe.

The added bonus is that a keyboard-inclined user will be able to choose 
between the two solely by typing.

Of course a different UI paradigm could create a different answer (of 
the "selection" rather than "completion" variety). But for generic code, 
we cannot yet rely on that UI being available. Or suitable for all users 
(if we're talking about fido-vertical-mode, which is in the core).