rust/tests/ui/regions/regions-trait-object-subtyping.rs
2023-01-11 09:32:08 +00:00

27 lines
663 B
Rust

trait Dummy { fn dummy(&self); }
fn foo1<'a:'b,'b>(x: &'a mut (dyn Dummy+'a)) -> &'b mut (dyn Dummy+'b) {
// Here, we are able to coerce
x
}
fn foo2<'a:'b,'b>(x: &'b mut (dyn Dummy+'a)) -> &'b mut (dyn Dummy+'b) {
// Here, we are able to coerce
x
}
fn foo3<'a,'b>(x: &'a mut dyn Dummy) -> &'b mut dyn Dummy {
// Without knowing 'a:'b, we can't coerce
x
//~^ ERROR lifetime may not live long enough
}
struct Wrapper<T>(T);
fn foo4<'a:'b,'b>(x: Wrapper<&'a mut dyn Dummy>) -> Wrapper<&'b mut dyn Dummy> {
// We can't coerce because it is packed in `Wrapper`
x
//~^ ERROR lifetime may not live long enough
}
fn main() {}