src/test/ui/specialization/issue-70442.rs

   1 #![feature(specialization)] //~ WARN the feature `specialization` is incomplete
   2
   3 // check-pass
   4
   5 trait Trait {
   6     type Assoc;
   7 }
   8
   9 impl<T> Trait for T {
  10     default type Assoc = bool;
  11 }
  12
  13 // This impl inherits the `Assoc` definition from above and "locks it in", or finalizes it, making
  14 // child impls unable to further specialize it. However, since the specialization graph didn't
  15 // correctly track this, we would refuse to project `Assoc` from this impl, even though that should
  16 // happen for items that are final.
  17 impl Trait for () {}
  18
  19 fn foo<X: Trait<Assoc=bool>>() {}
  20
  21 fn main() {
  22     foo::<()>();  // `<() as Trait>::Assoc` is normalized to `bool` correctly
  23 }