mirror of https://github.com/rust-lang/rust
161 lines
3.6 KiB
Rust
161 lines
3.6 KiB
Rust
// Regression test for #61320
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// This is the same issue as #61311, just a larger test case.
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//@ check-pass
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pub struct AndThen<A, B, F>
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where
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A: Future,
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B: IntoFuture,
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{
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state: (A, B::Future, F),
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}
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pub struct FutureResult<T, E> {
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inner: Option<Result<T, E>>,
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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) -> Poll<T, E> {
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unimplemented!()
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}
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}
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pub type Poll<T, E> = Result<T, E>;
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impl<A, B, F> Future for AndThen<A, B, F>
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where
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A: Future,
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B: IntoFuture<Error = A::Error>,
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F: FnOnce(A::Item) -> B,
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{
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type Item = B::Item;
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type Error = B::Error;
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fn poll(&mut self) -> Poll<B::Item, B::Error> {
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unimplemented!()
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}
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}
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pub trait Future {
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type Item;
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type Error;
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fn poll(&mut self) -> Poll<Self::Item, Self::Error>;
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fn and_then<F, B>(self, f: F) -> AndThen<Self, B, F>
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where
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F: FnOnce(Self::Item) -> B,
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B: IntoFuture<Error = Self::Error>,
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Self: Sized,
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{
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unimplemented!()
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}
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}
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pub trait IntoFuture {
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/// The future that this type can be converted into.
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type Future: Future<Item = Self::Item, Error = Self::Error>;
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/// The item that the future may resolve with.
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type Item;
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/// The error that the future may resolve with.
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type Error;
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/// Consumes this object and produces a future.
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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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impl<F: ?Sized + Future> Future for ::std::boxed::Box<F> {
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type Item = F::Item;
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type Error = F::Error;
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fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
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(**self).poll()
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}
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}
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impl<T, E> IntoFuture for Result<T, E> {
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type Future = FutureResult<T, E>;
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type Item = T;
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type Error = E;
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fn into_future(self) -> FutureResult<T, E> {
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unimplemented!()
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}
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}
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struct Request<T>(T);
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trait RequestContext {}
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impl<T> RequestContext for T {}
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struct NoContext;
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impl AsRef<NoContext> for NoContext {
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fn as_ref(&self) -> &Self {
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&NoContext
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}
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}
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type BoxedError = Box<dyn std::error::Error + Send + Sync>;
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type DefaultFuture<T, E> = Box<dyn Future<Item = T, Error = E> + Send>;
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trait Guard: Sized {
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type Result: IntoFuture<Item = Self, Error = BoxedError>;
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fn from_request(request: &Request<()>) -> Self::Result;
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}
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trait FromRequest: Sized {
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type Context;
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type Future: Future<Item = Self, Error = BoxedError> + Send;
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fn from_request(request: Request<()>) -> Self::Future;
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}
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struct MyGuard;
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impl Guard for MyGuard {
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type Result = Result<Self, BoxedError>;
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fn from_request(_request: &Request<()>) -> Self::Result {
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Ok(MyGuard)
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}
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}
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struct Generic<I> {
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_inner: I,
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}
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impl<I> FromRequest for Generic<I>
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where
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MyGuard: Guard,
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<MyGuard as Guard>::Result: IntoFuture<Item = MyGuard, Error = BoxedError>,
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<<MyGuard as Guard>::Result as IntoFuture>::Future: Send,
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I: FromRequest<Context = NoContext>,
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{
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type Future = DefaultFuture<Self, BoxedError>;
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type Context = NoContext;
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fn from_request(headers: Request<()>) -> DefaultFuture<Self, BoxedError> {
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let _future = <MyGuard as Guard>::from_request(&headers)
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.into_future()
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.and_then(move |_| {
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<I as FromRequest>::from_request(headers)
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.into_future()
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.and_then(move |fld_inner| Ok(Generic { _inner: fld_inner }).into_future())
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});
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panic!();
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}
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}
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fn main() {}
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