Exit with negative numbers causes assertion failure

[IsaacOscar]

I probably shoudln't be doing this, but when I use the exit builtin with a negative number, I get an assertion failure. For example, running fish -c 'exit -1' gives:

warning: builtin exit returned invalid exit code -1
error: /home/abuild/rpmbuild/BUILD/fish-3.6.0/src/proc.h:97: failed assertion: ret >= 0 && "trying to create proc_status_t from failed wait{,id,pid}() call" " or invalid builtin exit code!"
error: Backtrace:
0   fish(+0xf4eba) [0x559073362eba]
1   fish(+0xf837c) [0x55907336637c]
2   fish(+0x138db1) [0x5590733a6db1]
3   fish(+0x13a6fe) [0x5590733a86fe]
4   fish(+0x13a85b) [0x5590733a885b]
5   fish(+0x73943) [0x5590732e1943]
6   fish(+0x1fb77) [0x55907328db77]
7   fish(+0x15a04) [0x559073283a04]
8   /lib64/libc.so.6(+0x27af0) [0x7fd1b6735af0]
9   __libc_start_main + 139
10  fish(+0x18285) [0x559073286285]

fish: Job 1, 'fish -c 'exit -1'' terminated by signal SIGABRT (Abort)

Note that the crash is in the fish that I just spawned to run exit -1, not the shell used to spawn fish.

Version Information:

• fish --version reports fish, version 3.6.0
• uname -a reports Linux DESKTOP-38G9TM7 5.15.90.1-microsoft-standard-WSL2 #1 SMP Fri Jan 27 02:56:13 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
• I'm running openSUSE Tumbleweed (version 20230304) in WSL version 1.1.3.0
• My terminal is "Windows Terminal"
• Runing with fish under env HOME=$(mktemp -d) makes no difference