20 lines
503 B
Rust
20 lines
503 B
Rust
// run-pass
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trait Future: 'static {
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// The requirement for Self: Sized must prevent instantiation of
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// Future::forget in vtables, otherwise there's an infinite type
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// recursion through <Map<...> as Future>::forget.
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fn forget(self) where Self: Sized {
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Box::new(Map(self)) as Box<dyn Future>;
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}
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}
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struct Map<A>(#[allow(unused_tuple_struct_fields)] A);
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impl<A: Future> Future for Map<A> {}
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pub struct Promise;
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impl Future for Promise {}
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fn main() {
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Promise.forget();
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}
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