struct X<'a> {
    v: &'a mut u32,
}

fn v<'a>(x: &'a mut X<'a>) -> &'a mut u32 { x.v }

fn b<'a>(x: &'a mut X<'a>) -> u32 {
    let u = *v(x);
    let v = *v(x);
    u + v
}

fn main() {
    let mut x = 0;
    b(&mut X { v: &mut x });
}