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// edition:2018
#![feature(type_alias_impl_trait)]
use std::future::Future;
trait SearchableResource<Criteria> {
type SearchResult;
}
trait SearchableResourceExt<Criteria>: SearchableResource<Criteria> {
type Future<'f, A: 'f + ?Sized, B: 'f>: Future<Output = Result<Vec<A::SearchResult>, ()>> + 'f
where
A: SearchableResource<B>,
Self: 'f;
fn search<'c>(&'c self, client: &'c ()) -> Self::Future<'c, Self, Criteria>;
}
type SearchFutureTy<'f, A, B: 'f>
where
A: SearchableResource<B> + ?Sized + 'f,
= impl Future<Output = Result<Vec<A::SearchResult>, ()>> + 'f;
impl<T, Criteria> SearchableResourceExt<Criteria> for T
where
T: SearchableResource<Criteria>,
{
type Future<'f, A, B: 'f> = SearchFutureTy<'f, A, B>
where
A: SearchableResource<B> + ?Sized + 'f,
Self: 'f;
fn search<'c>(&'c self, _client: &'c ()) -> Self::Future<'c, Self, Criteria> {
async move { todo!() }
//~^ ERROR: the size for values of type `A` cannot be known at compilation time
}
}
fn main() {}
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