bug#36431: Crash in marker.c:337

[Eli Zaretskii]

> Date: Sat, 29 Jun 2019 13:17:34 +0200 (CEST)
> From: Werner LEMBERG <wl@gnu.org>
> 
> while sending an e-mail with `mew', I get the attached crash.  This is
> something new, which I haven't experienced before.  I can reliably
> repeat it.

Please send the reproduction recipe, preferably starting from "emacs
-Q", including any files required for the reproduction.  I don't think
it's possible to debug this otherwise, as the problem is clearly
data-dependent (somehow we end up requesting a byte-to-character
position conversion for a byte position that is not on character
boundary).

Thanks.