src/test/ui/generic-associated-types/issue-79636-1.rs

   1 #![feature(generic_associated_types)]
   2
   3 trait Monad {
   4     type Unwrapped;
   5     type Wrapped<B>;
   6
   7     fn bind<B, F>(self, f: F) -> Self::Wrapped<B> {
   8         todo!()
   9     }
  10 }
  11
  12 fn join<MOuter, MInner, A>(outer: MOuter) -> MOuter::Wrapped<A>
  13 where
  14     MOuter: Monad<Unwrapped = MInner>,
  15     MInner: Monad<Unwrapped = A, Wrapped = MOuter::Wrapped<A>>,
  16     //~^ ERROR: missing generics for associated type `Monad::Wrapped`
  17 {
  18     outer.bind(|inner| inner)
  19 }
  20
  21 fn main() {
  22     assert_eq!(join(Some(Some(true))), Some(true));
  23 }