Function replace_with_or_abort

pub fn replace_with_or_abort<T, F: FnOnce(T) -> T>(dest: &mut T, f: F)

Temporarily takes ownership of a value at a mutable location, and replace it with a new value based on the old one. Aborts on panic.

We move out of the reference temporarily, to apply a closure f, returning a new value, which is then placed at the original value’s location.

An important note

On panic (or to be more precise, unwinding) of the closure f, the process will abort to avoid returning control while dest is in a potentially invalid state.

If this behaviour is undesirable, use replace_with or replace_with_or_default.

Equivalent to replace_with(dest, || process::abort(), f).

Example

enum States {
    A(String),
    B(String),
}

impl States {
    fn poll(&mut self) {
        replace_with_or_abort(self, |self_| match self_ {
            States::A(a) => States::B(a),
            States::B(a) => States::A(a),
        });
    }
}