Game crashed when taking a flight of stairs up in Valley of the dead level.

Following lines were printed in the console as the crash occurred:

Suddenly, the dungeon collapses.
To report this error, contact root or games
and it may be possible to rebuild.

u_on_newpos: trying to place hero off map <80,0>

Unsure if this has been fixed already, as I realized that I've been playing a WIP version of the game:

Unix NetHack Version 3.7.0-16 Work-in-progress - last build Sun Feb 23 20:48:32 2020
(cbdda9dc9da8448d4f0a1f2f6c3e0baee906b50d,branch:NetHack-3.7).

Created the issue nevertheless, just in case I've managed to hit a genuinely new issue.