Rare crash in echo_location t_at

[NetSysFire]

My notdnethack game crashed on hardfought with the following trace:

Stack trace of thread 2260133:
                #0  0x00005bdc6cdfaeeb t_at (notdnethack-20240210-172536 + 0x8bbeeb)
                #1  0x00005bdc6c71dfa9 echo_location (notdnethack-20240210-172536 + 0x1defa9)
                #2  0x00005bdc6c5a4595 moveloop (notdnethack-20240210-172536 + 0x65595)
                #3  0x00005bdc6cfed20e main (notdnethack-20240210-172536 + 0xaae20e)
                #4  0x00007ed587429d90 n/a (/lib/x86_64-linux-gnu/libc.so.6 + 0x29d90)

Demo said it is very likely an upstream dnh bug.

14:48 <Demo> wow
14:48 <Demo> never seen echolocation crash trying to fuck with a presumably non isok() set of coords being passed go t_at
14:48 <Demo> assuming that's probably what happened
14:49 <Demo> likely a dnh bug but idk cause idk what caused it but ndnh hasn't messed with stuff I can think of that would reasonably change how any of that works
15:00 <NetSysFire> Demo: for reference this was in stygia. most of the water is pits
15:01 <NetSysFire> i think i was just waiting (555.) to wait for illithid staff invoke timeout to clear
15:02 <Demo> this sounds like a good candidate for a fuzzer but
15:02 <Demo> bug. and yet, I've never seen anything like that.
15:02 <Demo> I like to think that is the fuzzer's favorite thing to do. fuck a level up and then wait hundreds of turns
15:04 <NetSysFire> will you do the honors of reporting the bug or following up on it?
15:05 <Demo> no I'm probably just gonna let it get lost in this chat and my mind. I need to go drink a ton of caffeine and then jackhammer my head into a computer for 13 hours

This crash happened in Stygia on the square where I currently am in the screenshot. My role, the acu, has intrinsic echolocation and my race is incantifier. All the pits are the result of me draining the water for no reason with the dividing word. Please do not judge me. I was waiting (555.) for an artifact invocation timeout.

I can not reproduce this by waiting again. It was totally random. It was probably some monster that spawned if I had to guess.

Before anyone asks, the 2k maxhp bug is fixed in devel. That was what happened if you drank hundreds of potions of gain level.