[rustc.git] / src / test / ui / destructuring-assignment / warn-unused-duplication.rs

// run-pass

#![warn(unused_assignments)]

fn main() {
    let mut a;
    // Assignment occurs left-to-right.
    // However, we emit warnings when this happens, so it is clear that this is happening.
    (a, a) = (0, 1); //~ WARN value assigned to `a` is never read
    assert_eq!(a, 1);

    // We can't always tell when a variable is being assigned to twice, which is why we don't try
    // to emit an error, which would be fallible.
    let mut x = 1;
    (*foo(&mut x), *foo(&mut x)) = (5, 6);
    assert_eq!(x, 6);
}

fn foo<'a>(x: &'a mut u32) -> &'a mut u32 {
    x
}
Commit	Line	Data
29967ef6 XL	1	// run-pass
29967ef6 XL	2
29967ef6 XL	3	#![warn(unused_assignments)]
	4
	5	fn main() {
	6	let mut a;
	7	// Assignment occurs left-to-right.
	8	// However, we emit warnings when this happens, so it is clear that this is happening.
	9	(a, a) = (0, 1); //~ WARN value assigned to `a` is never read
	10	assert_eq!(a, 1);
	11
	12	// We can't always tell when a variable is being assigned to twice, which is why we don't try
	13	// to emit an error, which would be fallible.
	14	let mut x = 1;
	15	(foo(&mut x), foo(&mut x)) = (5, 6);
	16	assert_eq!(x, 6);
	17	}
	18
	19	fn foo<'a>(x: &'a mut u32) -> &'a mut u32 {
	20	x
	21	}