#![feature(generic_associated_types)]

trait MyFn {
    type Output<'a>;   // <-- we added <'a> to make it generic
    fn call(&self) -> Self::Output;
}

impl<T> MyFn for Baz<T> {
    type Output<'a> = &'a T;
    fn call(&self) -> Self::Output {
        &self.0
    }
}

struct Baz<T>(T);

fn make_baz<T>(t: T) -> Box<for<'a> MyFn<Output<'a> = &'a T>> {
    Box::new(Baz(t))
}


fn main() {
    let outside = {
        let s = "hi".to_string();
        let baz = make_baz(&s);  // <-- NOW BORROWED!
        println!("{}", baz.call()); // works

        baz
    };

    println!("{}", outside.call()); // doesn't work!
}