bug#31062: 26.0.91; warning on UTF-8 encoding of unibyte text

[Eli Zaretskii]

> Date: Wed, 04 Apr 2018 20:26:52 +0200
> From: charles@aurox.ch (Charles A. Roelli)
> 
> emacs -q
> C-x b test RET
> M-: (insert-byte 195 1) RET
> M-: (insert-byte 188 1) RET   > buffer text should look like \303\274
> C-x C-s /tmp/foo RET          > the path is irrelevant
> 
> There's this warning:
> 
> These default coding systems were tried to encode text
> in the buffer ‘test’:
>   (utf-8-unix (1 . 4194243) (2 . 4194236))
> However, each of them encountered characters it couldn’t encode:
>   utf-8-unix cannot encode these: \303 \274
> 
> Is the text "(1 . 4194243) (2 . 4194236)" useful here?

It shows the positions and the codepoints of the offending characters,
and the coding-system that was tried.