rustc: references can escape their lifetime via trait objects

[aturon]

A trait impl on a reference can be used to violate lifetimes via trait objects. The following segfaults on my OSX machine:

trait Oops {
    fn expose<'b>(&'b self) -> &'b Vec<u8>;
}

impl<'a> Oops for &'a Vec<u8> {
    fn expose<'b>(&'b self) -> &'b Vec<u8> {
        *self
    }
}

fn hide(x: &Vec<u8>) -> Box<Oops> {
    box x as Box<Oops>
}

fn hidden_pointer_into_frame() -> Box<Oops> {
    let v = vec!(37);
    hide(&v)
}

fn main() {
    let hp: Box<Oops> = hidden_pointer_into_frame();
    let p: &Vec<u8> = hp.expose();
    println!("{}", *p)
}

[aturon]

Possibly an instance of #2203, but I'm not sure.

[aturon]

Actually, this is almost certainly a dupe of one of #11374, #5723, #11971 or #12781.

Closing.