src/test/ui/impl-trait/issues/issue-84073.rs

   1 use std::marker::PhantomData;
   2
   3 pub trait StatefulFuture<S> {}
   4 pub struct Never<T>(PhantomData<T>);
   5 impl<T> StatefulFuture<T> for Never<T> {}
   6
   7 pub struct RaceBuilder<F, S> {
   8     future: F,
   9     _phantom: PhantomData<S>,
  10 }
  11
  12 impl<T, F> RaceBuilder<T, F>
  13 where
  14     F: StatefulFuture<Option<T>>,
  15 {
  16     pub fn when(self) {}
  17 }
  18
  19 pub struct Race<T, R> {
  20     race: R,
  21     _phantom: PhantomData<T>,
  22 }
  23
  24 impl<T, R> Race<T, R>
  25 where
  26     R: Fn(RaceBuilder<T, Never<T>>),
  27 {
  28     pub fn new(race: R) {}
  29 }
  30
  31 fn main() {
  32     Race::new(|race| race.when()); //~ ERROR type annotations needed
  33 }