[steveklabnik]

Rust, the language, strictly speaking, knows nothing about allocation at all.

The standard library assumes infallible allocation currently. Kernels generally do not use the standard library.

(Okay, STRICTLY speaking there’s a hack for Box<T> in the language right now but it’s not about the allocation part and Box<T> is technically defined in the standard library with Magic(tm) and so isn’t relevant in an OS dev context, as you won’t use the standard library and therefore Box<T>. Rust-the-language never implicitly inserts heap allocations, including Box<T>, anywhere.)