77 lines
2.2 KiB
Rust
77 lines
2.2 KiB
Rust
// edition:2021
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// [next] compile-flags: -Zlower-impl-trait-in-trait-to-assoc-ty
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// revisions: current next
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#![feature(return_position_impl_trait_in_trait)]
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#![allow(incomplete_features)]
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use std::future::Future;
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trait Captures<'a> {}
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impl<T> Captures<'_> for T {}
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trait Captures2<'a, 'b> {}
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impl<T> Captures2<'_, '_> for T {}
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pub trait AsyncTrait {
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fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>;
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fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>>;
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fn async_fn_multiple<'a>(&'a self, buff: &[u8])
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-> impl Future<Output = Vec<u8>> + Captures<'a>;
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fn async_fn_reduce_outlive<'a, T>(
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&'a self,
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buff: &[u8],
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t: T,
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) -> impl Future<Output = Vec<u8>> + 'a;
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fn async_fn_reduce<'a, T>(
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&'a self,
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buff: &[u8],
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t: T,
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) -> impl Future<Output = Vec<u8>> + Captures<'a>;
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}
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pub struct Struct;
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impl AsyncTrait for Struct {
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fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
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//~^ ERROR return type captures more lifetimes than trait definition
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async move { buff.to_vec() }
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}
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fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
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//~^ ERROR return type captures more lifetimes than trait definition
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async move { buff.to_vec() }
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}
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fn async_fn_multiple<'a, 'b>(
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&'a self,
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buff: &'b [u8],
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) -> impl Future<Output = Vec<u8>> + Captures2<'a, 'b> {
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//~^ ERROR return type captures more lifetimes than trait definition
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async move { buff.to_vec() }
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}
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fn async_fn_reduce_outlive<'a, 'b, T>(
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&'a self,
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buff: &'b [u8],
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t: T,
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) -> impl Future<Output = Vec<u8>> {
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//~^ ERROR the parameter type `T` may not live long enough
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async move {
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let _t = t;
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vec![]
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}
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}
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// OK: We remove the `Captures<'a>`, providing a guarantee that we don't capture `'a`,
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// but we still fulfill the `Captures<'a>` trait bound.
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fn async_fn_reduce<'a, 'b, T>(&'a self, buff: &'b [u8], t: T) -> impl Future<Output = Vec<u8>> {
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async move {
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let _t = t;
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vec![]
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}
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}
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}
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fn main() {}
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