Re: [Patch] Enable byte-compile-error-on-wran for error-free files in lisp/

[Eli Zaretskii]

> From: Richard Stallman <address@hidden>
> Date: Fri, 23 Feb 2018 04:47:24 -0500
> Cc: address@hidden
> 
>   > - there are various situations where there's no really good replacement.
> 
> Maybe that means we shouldn't declare them obsolete.

No, I think we should continue declaring them obsolete, because in
many cases they are used incorrectly, and produce subtle bugs.  For
example, in some locales, string-make-unibyte produces the same
results as encode-coding-string, so people could mistakenly use the
former instead of the latter, if that happens to work in their locale.

> Can you describe some of these situations and what the problem is?

One such case is in ruler.el; search for "unibyte".  This use case
could be fixed by adding an optional argument to make-string, which
would force it to always produce a multibyte string -- that's the kind
of alternatives I had in mind, which should help us get rid of these
obsolete functions in the few legitimate uses we still have.