#![feature(nll)]

fn get_or_insert<T: Eq>(vec: &mut Vec<T>, x: T) -> &mut T {
    {
        if let Some(y) = vec.iter_mut().find(|z| *z == &x) {
            return y
        }
    }

    {
        vec.push(x);
        vec.last_mut().unwrap()
    }
}

fn main() {}