[rustc.git] / src / test / ui / array-slice-vec / variance-vec-covariant.rs

// 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);
}
Commit	Line	Data
b7449926	1	// run-pass
223e47cc	2
b7449926	3	// Test that vec is now covariant in its argument type.
c34b1796	4
85aaf69f	5	#![allow(dead_code)]
223e47cc	6
85aaf69f SL	7	fn foo<'a,'b>(v1: Vec<&'a i32>, v2: Vec<&'b i32>) -> i32 {
	8	bar(v1, v2).cloned().unwrap_or(0) // only type checks if we can intersect 'a and 'b
	9	}
223e47cc	10
85aaf69f SL	11	fn bar<'c>(v1: Vec<&'c i32>, v2: Vec<&'c i32>) -> Option<&'c i32> {
	12	v1.get(0).cloned().or_else(\|\| v2.get(0).cloned())
	13	}
	14
	15	fn main() {
	16	let x = 22;
	17	let y = 44;
	18	assert_eq!(foo(vec![&x], vec![&y]), 22);
	19	assert_eq!(foo(vec![&y], vec![&x]), 44);
223e47cc	20	}