超出范围后，为什么字符串文字不消失？

Question

test超出范围后不应该消失吗？为什么println!仍可以打印test的值？

fn skip<'a>(line: &'a str, _prefix: &'a str) -> &'a str {
    line
}

fn main() {
    let line = "aaa";
    let q;
    {
        let test = "bbb";
        q = skip(test, line);
    }
    println!("{}", q);
}