src/test/ui/generic-associated-types/issue-93341.rs

   1 // check-pass
   2
   3 use std::marker::PhantomData;
   4
   5 pub struct Id<'id>(PhantomData<fn(&'id ()) -> &'id ()>);
   6
   7 fn new_id() -> Id<'static> {
   8     Id(PhantomData)
   9 }
  10
  11 pub trait HasLifetime where {
  12     type AtLifetime<'a>;
  13 }
  14
  15 pub struct ExistentialLifetime<S: HasLifetime>(S::AtLifetime<'static>);
  16
  17 impl<S: HasLifetime> ExistentialLifetime<S> {
  18     pub fn new<F>(f: F) -> ExistentialLifetime<S>
  19         where for<'id> F: FnOnce(Id<'id>) -> S::AtLifetime<'id> {
  20         ExistentialLifetime(f(new_id()))
  21     }
  22 }
  23
  24
  25 struct ExampleS<'id>(Id<'id>);
  26
  27 struct ExampleMarker;
  28
  29 impl HasLifetime for ExampleMarker {
  30     type AtLifetime<'id> = ExampleS<'id>;
  31 }
  32
  33
  34 fn broken0() -> ExistentialLifetime<ExampleMarker> {
  35     fn new_helper<'id>(id: Id<'id>) -> ExampleS<'id> {
  36         ExampleS(id)
  37     }
  38
  39     ExistentialLifetime::<ExampleMarker>::new(new_helper)
  40 }
  41
  42 fn broken1() -> ExistentialLifetime<ExampleMarker> {
  43     fn new_helper<'id>(id: Id<'id>) -> <ExampleMarker as HasLifetime>::AtLifetime<'id> {
  44         ExampleS(id)
  45     }
  46
  47     ExistentialLifetime::<ExampleMarker>::new(new_helper)
  48 }
  49
  50 fn broken2() -> ExistentialLifetime<ExampleMarker> {
  51     ExistentialLifetime::<ExampleMarker>::new(|id| ExampleS(id))
  52 }
  53
  54 fn main() {}