bug#43632: Raw bytes printed as latin-1 in echo area and *Messages*

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Sat, 26 Sep 2020 14:51:22 +0200
> 
>  M-: "\377"
>  => "ÿ"
> 
> in both the echo area and in *Messages*. The expected message is "\377".
> 
> The same thing happens with
> 
>  (prin1 "\377" t)
> 
> This anomaly was first observed by Lars Ingebrigtsen.

It is not an anomaly.  If you want to see escapes, set
print-escape-nonascii non-nil.

Also note that what you see is the result of 'eval' printing the
result, the real result (as returned by prin1) is a unibyte string:

  (multibyte-string-p (prin1 "\377")) => nil

(Yes, this is very confusing.)