1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
13 struct DerefWithHelper<H, T> {
19 fn helper_borrow(&self) -> &T;
22 impl<T> Helper<T> for Option<T> {
23 fn helper_borrow(&self) -> &T {
24 self.as_ref().unwrap()
28 impl<T, H: Helper<T>> Deref for DerefWithHelper<H, T> {
31 fn deref(&self) -> &T {
32 self.helper.helper_borrow()
39 fn foo(&self) -> int {self.x}
43 let x: DerefWithHelper<Option<Foo>, Foo> =
44 DerefWithHelper { helper: Some(Foo {x: 5}), value: Foo { x: 2 } };
45 assert!(x.foo() == 5);