| // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // Test that vec is now covariant in its argument type. |
| |
| |
| #![allow(dead_code)] |
| #![feature(core)] |
| |
| fn foo<'a,'b>(v1: Vec<&'a i32>, v2: Vec<&'b i32>) -> i32 { |
| bar(v1, v2).cloned().unwrap_or(0) // only type checks if we can intersect 'a and 'b |
| } |
| |
| fn bar<'c>(v1: Vec<&'c i32>, v2: Vec<&'c i32>) -> Option<&'c i32> { |
| v1.get(0).cloned().or_else(|| v2.get(0).cloned()) |
| } |
| |
| fn main() { |
| let x = 22; |
| let y = 44; |
| assert_eq!(foo(vec![&x], vec![&y]), 22); |
| assert_eq!(foo(vec![&y], vec![&x]), 44); |
| } |
