In Rust, if you want a deep copy you (IIRC) implement the Clone trait, which allows you to explicitly clone everything. Many collections in the standard library already implement this, so you get it by default :).
Edit: I should point out that deep copies can only be explicit in Rust -- there's no implicit deep copy AFAIK.
There is no implicit deep copy, Clone is usually how a deep copy is implemented, but not all Clones are deep copies. Rc, for example, bumps a reference count on Clone.
Edit: I should point out that deep copies can only be explicit in Rust -- there's no implicit deep copy AFAIK.