rust 0.6: Internal Compiler Error when compiling the following code

[qtigercom]

trait IDummy {
    fn do_nothing(&self);
}

struct A { a: int }
struct B<'self> { b: int, pa: &'self A }

    impl IDummy for A {
        fn do_nothing(&self) {
            io::println("A::do_nothing() is called");
        }
    }

impl<'self> B<'self> {
    fn get_pa(&self) -> &'self IDummy { self.pa as &'self IDummy }
}


#[test]
fn test_borrowed_ptr() {
    let sa = A { a: 100 };
    let sb = B { b: 200, pa: &sa };

    io::println(fmt!("sa is %?", sa));
    io::println(fmt!("sb is %?", sb));

    io::println(fmt!("sb.pa is %?", sb.get_pa()));
}

[Blei]

Still relevant on master.

blorg.rs:15:40: 15:64 error: internal compiler error: Cannot relate bound region as subregion: br_self
blorg.rs:15     fn get_pa(&self) -> &'self IDummy { self.pa as &'self IDummy }
                                                    ^~~~~~~~~~~~~~~~~~~~~~~~