给出的示例为

fn main() {
    let v = 0u64;
    let mut a = A {
        x: "hello".to_string(),
        y: &v,
    };
    a.hello();
    a.world();
}
struct A<'a> {
    x: String,
    y: &'a u64,
}
impl<'a> A<'a> {
    fn hello(&'a mut self) {
        self.world();
        self.x = "hello123".to_string();
        let _ = *self.y;
        self.world();
    }
    fn world(&mut self) {
        self.x = "world".to_string();
    }
}

字符串
生成它会产生错误，因为

|
9  |     a.hello();
   |     --------- first mutable borrow occurs here
10 |     a.world();
   |     ^^^^^^^^^
   |     |
   |     second mutable borrow occurs here
   |     first borrow later used here

型
然而，改变A::hello的签名（即消除显式的'a注解）

fn hello(&mut self)

型
将修复程序。