fn shorten<'a, 'lower, T>(x: &'a T) -> &'lower T
where
    'a: 'lower,
    T: ?Sized,
{
    x
}

fn main()
{
    let fnptr = &shorten;
    let ptr = {
        let b = vec![1];
        let c = fnptr(&b);
        c
    };

    println!("ptr = {:?}", ptr);

}