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//@ check-pass
use std::marker::PhantomData;
pub struct Id<'id>(PhantomData<fn(&'id ()) -> &'id ()>);
fn new_id() -> Id<'static> {
Id(PhantomData)
}
pub trait HasLifetime where {
type AtLifetime<'a>;
}
pub struct ExistentialLifetime<S: HasLifetime>(S::AtLifetime<'static>);
impl<S: HasLifetime> ExistentialLifetime<S> {
pub fn new<F>(f: F) -> ExistentialLifetime<S>
where for<'id> F: FnOnce(Id<'id>) -> S::AtLifetime<'id> {
ExistentialLifetime(f(new_id()))
}
}
struct ExampleS<'id>(Id<'id>);
struct ExampleMarker;
impl HasLifetime for ExampleMarker {
type AtLifetime<'id> = ExampleS<'id>;
}
fn broken0() -> ExistentialLifetime<ExampleMarker> {
fn new_helper<'id>(id: Id<'id>) -> ExampleS<'id> {
ExampleS(id)
}
ExistentialLifetime::<ExampleMarker>::new(new_helper)
}
fn broken1() -> ExistentialLifetime<ExampleMarker> {
fn new_helper<'id>(id: Id<'id>) -> <ExampleMarker as HasLifetime>::AtLifetime<'id> {
ExampleS(id)
}
ExistentialLifetime::<ExampleMarker>::new(new_helper)
}
fn broken2() -> ExistentialLifetime<ExampleMarker> {
ExistentialLifetime::<ExampleMarker>::new(|id| ExampleS(id))
}
fn main() {}
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