Eli Zaretskii <eliz@gnu.org> schrieb am Sa., 29. Juli 2017 um 19:22 Uhr:

> > Date: Sat, 29 Jul 2017 12:34:46 -0400
> > From: Mark Oteiza <mvoteiza@udel.edu>
> > Cc: emacs-devel@gnu.org
> >
> > >So I think the problem happens in unidata-word-list-compress, and it
> > >happens because make-vector, which that function calls always returns
> > >the same vector, so the vectors used by that function and created by
> > >it are all messed up.
> >
> > I don't follow: why does it always return the same vector?
>
> That's how I understand what the byte compiler does when you declare
> that function "pure".
>

That sounds like a bug. Optimization shouldn't change semantics. Either we
need to change the definition of "pure" to something far more restrictive,
or we should fix the optimizer.