rust/tests/ui/regions/regions-variance-covariant-use-covariant.rs
2023-01-11 09:32:08 +00:00

24 lines
664 B
Rust

// run-pass
#![allow(dead_code)]
// Test that a type which is covariant with respect to its region
// parameter is successful when used in a covariant way.
//
// Note: see ui/variance/variance-regions-*.rs for the tests that
// check that the variance inference works in the first place.
// This is covariant with respect to 'a, meaning that
// Covariant<'foo> <: Covariant<'static> because
// 'foo <= 'static
// pretty-expanded FIXME #23616
struct Covariant<'a> {
f: extern "Rust" fn(&'a isize)
}
fn use_<'a>(c: Covariant<'a>) {
// OK Because Covariant<'a> <: Covariant<'static> iff 'a <= 'static
let _: Covariant<'static> = c;
}
pub fn main() {}