60 lines
1.1 KiB
Rust
60 lines
1.1 KiB
Rust
//@ build-fail
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//@ edition: 2021
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#![feature(async_closure, noop_waker)]
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use std::future::Future;
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use std::pin::pin;
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use std::task::*;
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pub fn block_on<T>(fut: impl Future<Output = T>) -> T {
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let mut fut = pin!(fut);
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// Poll loop, just to test the future...
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let ctx = &mut Context::from_waker(Waker::noop());
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loop {
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match fut.as_mut().poll(ctx) {
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Poll::Pending => {}
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Poll::Ready(t) => break t,
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}
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}
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}
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trait Blah {
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async fn iter<T>(&mut self, iterator: T)
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where
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T: IntoIterator<Item = ()>;
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}
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impl Blah for () {
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async fn iter<T>(&mut self, iterator: T)
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//~^ ERROR recursion in an async fn requires boxing
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where
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T: IntoIterator<Item = ()>,
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{
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Blah::iter(self, iterator).await
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}
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}
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struct Wrap<T: Blah> {
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t: T,
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}
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impl<T: Blah> Wrap<T>
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where
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T: Blah,
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{
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async fn ice(&mut self) {
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//~^ ERROR a cycle occurred during layout computation
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let arr: [(); 0] = [];
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self.t.iter(arr.into_iter()).await;
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}
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}
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fn main() {
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block_on(async {
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let mut t = Wrap { t: () };
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t.ice();
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})
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}
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