fn type_id<T>(_x: T) -> fn() {
    || {}
}

fn main() {
    let x = 0;
    let xref = &x;
    let id_x = type_id(xref);
    let id_y;
    {
        let y = 1;
        let yref = &y;
        id_y = type_id(yref);
    }
    println!("{:?}, {:?}", id_x, id_y);
}