rust/tests/ui/regions/regions-free-region-ordering-callee.rs
2023-01-11 09:32:08 +00:00

31 lines
910 B
Rust

// Tests that callees correctly infer an ordering between free regions
// that appear in their parameter list. See also
// regions-free-region-ordering-caller.rs
fn ordering1<'a, 'b>(x: &'a &'b usize) -> &'a usize {
// It is safe to assume that 'a <= 'b due to the type of x
let y: &'b usize = &**x;
return y;
}
fn ordering2<'a, 'b>(x: &'a &'b usize, y: &'a usize) -> &'b usize {
// However, it is not safe to assume that 'b <= 'a
&*y
//~^ ERROR lifetime may not live long enough
}
fn ordering3<'a, 'b>(x: &'a usize, y: &'b usize) -> &'a &'b usize {
// Do not infer an ordering from the return value.
let z: &'b usize = &*x;
//~^ ERROR lifetime may not live long enough
panic!();
}
// see regions-free-region-ordering-callee-4.rs
fn ordering5<'a, 'b>(a: &'a usize, b: &'b usize, x: Option<&'a &'b usize>) {
let z: Option<&'a &'b usize> = None;
}
fn main() {}