mirror of
https://github.com/rust-lang/rust.git
synced 2024-11-24 07:44:10 +00:00
21 lines
503 B
Rust
21 lines
503 B
Rust
// 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);
|
|
}
|