fn main() {
    g(&mut vec![1,2]);
}

fn g(x: &mut Vec<usize>) {
    if 10 <= x.len() {
        println!("END");
        return;
    }
    x.push(x.len());
    // {
    //     let _y = x;
    // }
    h(x);
    g(x);
}

fn h(_x: &mut Vec<usize>) {}