bug#53896: 28.0.91; Icomplete Vertical Mode fails to preview "C-x 8 RET 8072"

[Eli Zaretskii <eliz@gnu.org>]

tags 53896 notabug
thanks

> Date: Wed, 9 Feb 2022 10:38:29 +0000 (UTC)
> From: Van Ly <van.ly@sdf.org>
> 
> The vertical listing in the minibuffer in response to "insert-char" fails to preview the match for "C-x 8 RET 8072".
> 
> observed behavior
> * start by "emacs -Q"
> * M-x customize RET
> * search "icomplete vertical"
> * toggle "on" Icomplete Vertical Mode 
> * switch to "*scratch*" buffer
> ; --------------------------------
> ; minibuffer fails to preview 8072
> ; --------------------------------
> * C-x 8 RET
> * continue typing "80" ;; shows LINEAR A SIGN A580, A800, A801, A802, A803, A804, A805
> * continue typing "807" ;; shows LINEAR A SIGN A807
> * continue typing "8072" ;; shows "8072 [No matches]"

This has nothing to do with icomplete-vertical-mode.  You will see the
same with the default completion:

  C-x 8 RET 8072 TAB

This shows [No match].

The reason is that we deliberately remove all the CJG IDEOGRAPH-NNNN
names from the list of character names we submit to "C-x 8 RET" as
possible completions.  We do that because there are gobs of those
characters, whose names mean nothing (they are not real names), and
whose existence in the completions would just add a lot of noise.

This is a feature, not a bug.