An example of this could be trying to mutably access disjoint parts of a Vec. The Rust language today doesn't understand that is safe today, because it would re

An example of this could be trying to mutably access disjoint parts of a Vec. The Rust language today doesn't understand that is safe today, because it would require tracking all indices used somehow to verify that the accesses are indeed disjoint. But you can write unsafe code to access those fields, or even better, use Vec::split_at_mut() which uses the unsafe code you'd have to write with the appropriate precondition checks to ensure you can't misuse it in a way that causes memory unsafety.