bug#43519: 28.0.50; Overlay at end of minibuf hides minibuf's real content

[Eli Zaretskii]

> Date: Tue, 22 Sep 2020 15:51:22 +0000
> From: Gregory Heytings <ghe@sdf.org>
> cc: monnier@iro.umontreal.ca, 43519@debbugs.gnu.org
> 
> See the two attached screenshots, taken with (setq max-mini-window-height 
> 1) and icomplete-mode.  "no-completion-candidates" is what a user will see 
> with your change, "completion-candidates" is what a user will see without 
> your change.
> 
> So your change has exactly the problem that you explained was so important 
> to avoid, and that I explained was an unlikely corner case.

Thanks.  Please describe the recipe to get this result starting from
"emacs -Q", so that I could look into it.