| //@ 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); | |
| } |