[steveklabnik]

Arenas exist in stable too, this is just the arena the compiler uses internally. See packages like https://crates.io/crates/generational-arena or https://crates.io/crates/typed-arena

[arcticbull]

Ah of course, my bad, I must not have noticed. For some reason I read the "internal" flag as "nightly" :P

[steveklabnik]

It's all good!