Hm, good point. (It's implemented as a Once (which is an atomic usize) and an UnsafeCell for holding the actual data.) And while using SyncOnceCell normally mig

Hm, good point. (It's implemented as a Once (which is an atomic usize) and an UnsafeCell for holding the actual data.) And while using SyncOnceCell normally might incur some small checking overhead on each access, you can use it to obtain a &'static. https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=506632ca984ccc6732114373c535ce28 https://play.rust-lang.org/?version=nightly&mode=debug&editi... But then, by tialaramex's logic, isn't it just as bad as Box::leak? (Maybe not quite as, because it can leak maximally one thing. You can't do this in a loop.)