bug#27986: 26.0.50; 'rename-file' can rename files without

[Eli Zaretskii]

> From: John Wiegley <jwiegley@gmail.com>
> Cc: rms@gnu.org,  27986@debbugs.gnu.org
> Date: Fri, 25 Aug 2017 13:33:46 -0700
> 
> >>>>> "EZ" == Eli Zaretskii <eliz@gnu.org> writes:
> 
> EZ> Thanks. I do indeed think that making this an error even if B is an empty
> EZ> directory would be better, as it will reveal the cases that need to be
> EZ> fixed more prominently.
> 
> I prefer that to renaming a directory when the target is a directory.  That's
> not how /bin/mv behaves, so I'd be surprised if (rename-file) did differently.
> Making the Emacs version more restrictive, however, makes sense.

Thanks.

Paul, it sounds like we have a consensus on this, so please go ahead
with the changes.  At least Richard, John, and myself prefer to signal
an error even when the target is an empty directory, so I hope the
non-interactive rename-file could do that after your changes.