src/test/ui/impl-trait/hidden-type-is-opaque.rs

   1 // check-pass
   2 #![feature(type_alias_impl_trait)]
   3
   4 fn reify_as() -> Thunk<impl ContFn> {
   5     Thunk::new(|mut cont| {
   6         cont.reify_as();
   7         cont
   8     })
   9 }
  10
  11 type Tait = impl ContFn;
  12
  13 fn reify_as_tait() -> Thunk<Tait> {
  14     Thunk::new(|mut cont| {
  15         cont.reify_as();
  16         cont
  17     })
  18 }
  19
  20 #[must_use]
  21 struct Thunk<F>(F);
  22
  23 impl<F> Thunk<F> {
  24     fn new(f: F) -> Self
  25     where
  26         F: FnOnce(Continuation) -> Continuation,
  27     {
  28         Thunk(f)
  29     }
  30 }
  31
  32 trait ContFn {}
  33
  34 impl<F: FnOnce(Continuation) -> Continuation> ContFn for F {}
  35
  36 struct Continuation;
  37
  38 impl Continuation {
  39     fn reify_as(&mut self) {}
  40 }
  41
  42 fn main() {}