50 lines
1.0 KiB
Rust
50 lines
1.0 KiB
Rust
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//@ check-pass
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//@ edition: 2021
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// Make sure that we infer the args of an async closure even if it's passed to
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// a function that requires the async closure implement `Fn*` but does *not* have
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// a `Future` bound on the return type.
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#![feature(async_closure)]
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use std::future::Future;
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trait TryStream {
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type Ok;
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type Err;
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}
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trait TryFuture {
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type Ok;
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type Err;
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}
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impl<F, T, E> TryFuture for F where F: Future<Output = Result<T, E>> {
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type Ok = T;
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type Err = E;
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}
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trait TryStreamExt: TryStream {
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fn try_for_each<F, Fut>(&self, f: F)
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where
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F: FnMut(Self::Ok) -> Fut,
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Fut: TryFuture<Ok = (), Err = Self::Err>;
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}
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impl<S> TryStreamExt for S where S: TryStream {
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fn try_for_each<F, Fut>(&self, f: F)
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where
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F: FnMut(Self::Ok) -> Fut,
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Fut: TryFuture<Ok = (), Err = Self::Err>,
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{ }
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}
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fn test(stream: impl TryStream<Ok = &'static str, Err = ()>) {
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stream.try_for_each(async |s| {
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s.trim(); // Make sure we know the type of `s` at this point.
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Ok(())
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});
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}
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fn main() {}
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