30 lines
959 B
Rust
30 lines
959 B
Rust
// Test that a type which is contravariant with respect to its region
|
|
// parameter yields an error when used in a covariant way.
|
|
//
|
|
// Note: see variance-regions-*.rs for the tests that check that the
|
|
// variance inference works in the first place.
|
|
|
|
use std::marker;
|
|
|
|
// This is contravariant with respect to 'a, meaning that
|
|
// Contravariant<'foo> <: Contravariant<'static> because
|
|
// 'foo <= 'static
|
|
struct Contravariant<'a> {
|
|
marker: marker::PhantomData<&'a()>
|
|
}
|
|
|
|
fn use_<'short,'long>(c: Contravariant<'short>,
|
|
s: &'short isize,
|
|
l: &'long isize,
|
|
_where:Option<&'short &'long ()>) {
|
|
|
|
// Test whether Contravariant<'short> <: Contravariant<'long>. Since
|
|
// 'short <= 'long, this would be true if the Contravariant type were
|
|
// covariant with respect to its parameter 'a.
|
|
|
|
let _: Contravariant<'long> = c;
|
|
//~^ ERROR lifetime may not live long enough
|
|
}
|
|
|
|
fn main() {}
|