parking_lot implementation tests fail under Miri due to compare_exchange_weak failures

[Ben Kimock]

compare_exchange_weak is allowed to spuriously fail. By default, Miri makes most calls fail so this panics when running tests:

once_cell/src/imp_pl.rs

Line 171 in 2cdfc1e

 Err(_) => debug_assert!(false), 

[Ralf Jung]

Looks like this code simply wants compare_exchange without the "weak", if it does not want to handle spurious failures?

[Alex Kladov]

Nah, that’s just a bug, it should have Err(INCOMPLETE) => (), branch

[Alex Kladov]

@RalfJung in case no-one has told you this yet, miri is very cool, thanks!