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

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