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// 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.
// run-pass
// Test that vec is now covariant in its argument type.
#![allow(dead_code)]
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);
}
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