src/test/ui/self/arbitrary_self_types_trait.rs

// run-pass
#![feature(arbitrary_self_types)]

use std::rc::Rc;

trait Trait {
    fn trait_method<'a>(self: &'a Box<Rc<Self>>) -> &'a [i32];
}

impl Trait for Vec<i32> {
    fn trait_method<'a>(self: &'a Box<Rc<Self>>) -> &'a [i32] {
        &***self
    }
}

fn main() {
    let v = vec![1,2,3];

    assert_eq!(&[1,2,3], Box::new(Rc::new(v)).trait_method());
}