rust/tests/ui/object-lifetime/object-lifetime-default-dyn...

31 lines
730 B
Rust

// Test that `dyn Bar<Item = XX>` uses `'static` as the default object
// lifetime bound for the type `XX`.
trait Foo<'a> {
type Item: 'a + ?Sized;
fn item(&self) -> Box<Self::Item> { panic!() }
}
trait Bar { }
impl<T> Foo<'_> for T {
type Item = dyn Bar;
}
fn is_static<T>(_: T) where T: 'static { }
// Here, we default to `dyn Bar + 'a`. Or, we *should*, but the
// current code forces us into a conservative, hacky path.
fn bar<'a>(x: &'a str) -> &'a dyn Foo<'a, Item = dyn Bar> { &() }
//~^ ERROR please supply an explicit bound
fn main() {
let s = format!("foo");
let r = bar(&s);
// If it weren't for the conservative path above, we'd expect an
// error here.
is_static(r.item());
}