80 lines
1.5 KiB
Rust
80 lines
1.5 KiB
Rust
// run-pass
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use std::marker;
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use std::mem;
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fn main() {
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let workers = (0..0).map(|_| result::<u32, ()>());
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drop(join_all(workers).poll());
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}
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trait Future {
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type Item;
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type Error;
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fn poll(&mut self) -> Result<Self::Item, Self::Error>;
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}
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trait IntoFuture {
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type Future: Future<Item=Self::Item, Error=Self::Error>;
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type Item;
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type Error;
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fn into_future(self) -> Self::Future;
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}
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impl<F: Future> IntoFuture for F {
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type Future = F;
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type Item = F::Item;
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type Error = F::Error;
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fn into_future(self) -> F {
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self
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}
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}
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struct FutureResult<T, E> {
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_inner: marker::PhantomData<(T, E)>,
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}
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fn result<T, E>() -> FutureResult<T, E> {
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loop {}
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}
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impl<T, E> Future for FutureResult<T, E> {
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type Item = T;
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type Error = E;
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fn poll(&mut self) -> Result<T, E> {
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loop {}
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}
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}
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struct JoinAll<I>
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where I: IntoIterator,
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I::Item: IntoFuture,
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{
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elems: Vec<<I::Item as IntoFuture>::Item>,
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}
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fn join_all<I>(_: I) -> JoinAll<I>
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where I: IntoIterator,
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I::Item: IntoFuture,
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{
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JoinAll { elems: vec![] }
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}
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impl<I> Future for JoinAll<I>
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where I: IntoIterator,
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I::Item: IntoFuture,
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{
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type Item = Vec<<I::Item as IntoFuture>::Item>;
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type Error = <I::Item as IntoFuture>::Error;
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fn poll(&mut self) -> Result<Self::Item, Self::Error> {
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let elems = mem::replace(&mut self.elems, Vec::new());
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Ok(elems.into_iter().map(|e| {
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e
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}).collect::<Vec<_>>())
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}
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}
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