bug#64903: 28.2; completion-at-point deletes next line(s) when completing a single character in elisp

[Eli Zaretskii]

> Date: Thu, 27 Jul 2023 16:10:23 +0000
> From:  Thalis Charakas via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> This bug happens with "emacs -q -Q"
> 
> When completing a single character with completion-at-point (M-C-i) in elsip,
> after you select the desiered completion, it is inserted in the buffer
> but some of the following lines are deleted. This does not happen when
> the line has two characters.
> 
> Examples are with "emacs -q -Q"
> 
> Example 1:
> - Write "(setq foo nil)" in scratch.
> - Go to the line before that and type "(".
> - Press M-C-i.
> - Select any outecome.
> The (setq foo nil) is no longer there.

Why do you consider this a bug?  The documentation of the command
says:

  Perform completion on the text around point.

It doesn't tell what it considers to be "text around point", but why
shouldn't it consider the line you say is deleted as "text around
point", and therefore replace it with the completion candidate you
select from the list?