bug#30668: 27.0.50; Error in `completing-read'

[Eli Zaretskii]

> Cc: p.stephani2@gmail.com, 30668@debbugs.gnu.org
> Date: Sat, 26 Jun 2021 09:38:30 -0400
> From:  Stefan Monnier via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> +(defun completion--prompt-end ()
> +  (let ((end (minibuffer-prompt-end)))
> +    (if (< (point) end)
> +        (user-error "Can't complete in prompt")
> +      end)))

Won't minibuffer--completion-prompt-end be a better name?