[Measter]

No, it isn't. Because that distinction is significant if you are using the language in an environment where those libraries are not available or suitable, such as the Linux project which uses a custom fork of Alloc which provides collections for different allocators.

[vacuity]

So, that is not done at the language level but the library level. Unless the compiler is modified for Linux, but even if it is, that's entirely bespoke and unstable. This is not comparable to Zig's design. I'm aware that anything can be done if the right things are implemented; I'm talking about what Rust-the-language currently does for control over allocation. If the answer comes down to "we're doing something custom", then the language is soewhat or largely sidestepped. C-the-language certainly doesn't have panics or exceptions, even though longjmp or a custom runtime could be used.

[steveklabnik]

Rust the language knows nothing about allocations. It’s purely a library concern.