How do I get an owned value out of a `Box`?

Question

What is the implementation for this function:

fn unbox(value: Box) -> T {
    // ???
}

The only function in the docume

Answer 1

Dereference the value:

fn unbox<T>(value: Box<T>) -> T {
    *value
}

---

Way back in pre-1.0 Rust, heap-allocated values were very special types, and they used the sigil ~ (as in ~T). Along the road to Rust 1.0, most of this special-casing was removed... but not all of it.

This particular speciality goes by the name "deref move", and there's a proto-RFC about supporting it as a first-class concept. Until then, the answer is "because Box is special".