Rust is not "runtime free". Rust needs a "minimal runtime", as stated on the project home page. You need at least a memory allocator. Even C programs are usually linked to a runtime library (like glibc).

Rust is usable with an extremely minimal runtime that approximates having no runtime at all (with #[no_std]). There are a few intrinsics you have to define, but none of them involve memory allocation. It also has a core crate that does not expose anything that requires allocation.

Interesting! I was unaware of the existence of #[no_std]. My mistake. Thanks for putting it right :)

- easily call C libraries, practically trivial. I hated using the FFI's in Java & C#.

There's many things I don't like about rust but the above list make it very hard to beat.