| use std::marker::PhantomData; |
| |
| pub trait StatefulFuture<S> {} |
| pub struct Never<T>(PhantomData<T>); |
| impl<T> StatefulFuture<T> for Never<T> {} |
| |
| pub struct RaceBuilder<F, S> { |
| future: F, |
| _phantom: PhantomData<S>, |
| } |
| |
| impl<T, F> RaceBuilder<T, F> |
| where |
| F: StatefulFuture<Option<T>>, |
| { |
| pub fn when(self) {} |
| } |
| |
| pub struct Race<T, R> { |
| race: R, |
| _phantom: PhantomData<T>, |
| } |
| |
| impl<T, R> Race<T, R> |
| where |
| R: Fn(RaceBuilder<T, Never<T>>), |
| { |
| pub fn new(race: R) {} |
| } |
| |
| fn main() { |
| Race::new(|race| race.when()); //~ ERROR overflow assigning `_` to `Option<_>` |
| } |
