> AFAIK, you still have to be very careful since data races based on data dependencies can never be excluded in general
Hmm. Maybe I don't understand what you're getting at here. It seems like you're suggesting something like a[b] = x could race in safe Rust because we don't know b in advance and maybe it ends up being the same in two threads ?
But Rust's borrow checker won't allow both threads to have the same mutable array a so this is ruled out. You're going to have to either give them immutable references to a, which then can't be modified and so there's no data race, or else they need different arrays.
This is boringly easy to get right in theory, Rust just has to do a lot of work to make it usable while still delivering excellent runtime performance.
