#[derive(Debug)]
struct MyRef<'a, T> {
    s: &'a T
}

impl<'a, T> MyRef<'a, T> {
    fn test1(&self) -> Self {
        Self { s: self.s }
    }

    fn test2(&self) -> MyRef<T> {
        Self { s: self.s }
    }

    fn test3(&self) -> MyRef<'a, T> {
        Self { s: self.s }
    }

    fn test4(&self) -> MyRef<'_, T> {
        Self { s: self.s }
    }

    fn test5<'b>(&'b self) -> MyRef<'_, T> {
        Self { s: self.s }
    }

    fn test6<'b>(&'b self) -> MyRef<'a, T> {
        Self { s: self.s }
    }

    fn test7<'b>(&'b self) -> MyRef<'b, T> {
        Self { s: self.s }
    }
}

fn main() {
    let s = String::from("this is string");
    let t1;
    let t2;
    let t3;
    let t4;
    let t5;
    let t6;
    let t7;

    {
        let sr = MyRef { s: &s };
        t1 = sr.test1();
        t2 = sr.test2();
        t3 = sr.test3();
        t4 = sr.test4();
        t5 = sr.test5();
        t6 = sr.test6();
        t7 = sr.test7();
    }
    dbg!(t1);
    dbg!(t2);
    dbg!(t3);
    dbg!(t4);
    dbg!(t5);
    dbg!(t6);
    dbg!(t7);
}