bug#67661: 30.0.50; *Completions* has started popping up for icomplete-in-buffer

[Eli Zaretskii <eliz@gnu.org>]

> Cc: juri@linkov.net
> From: Sean Whitton <spwhitton@spwhitton.name>
> Date: Wed, 06 Dec 2023 15:30:12 +0000
> 
> X-debbugs-cc: juri@linkov.net
> 
> Hello,
> 
> 1. emacs -q
> 2. (setopt icomplete-in-buffer t)
> 3. M-x icomplete-mode
> 4. M-x eshell
> 5. try to tab-complete something where there is more than one possible
>    completion, e.g. ls<TAB> in a directory with many files.
> 
> Previously you would get the icomplete in buffer completion.
> Now, additionally, *Completions* pops up, but it doesn't make sense to
> have both.

AFAICT, the above description of the problem is inaccurate.  The
*Completions* buffer would pop up in previous versions as well, but
only after a second TAB.  Whereas the in-buffer completion would show
after the first TAB.  Now in Emacs 30 after the first TAB nothing
happens, and after the second TAB you see the same display as
previously after the second TAB: both in-buffer completion and the
*Completions* buffer popped up.

So I think the problem is that the first TAB does NOT show in-buffer
completion anymore in the above scenario.