Merge pull request #80 from Nemo157/update-generators

Update to use std pin feature and work with latest rust nightly

.travis.yml

@@ -4,6 +4,7 @@ sudo: false
 
 script:
   - cargo test
+  - cargo clean
   - cargo test --manifest-path testcrate/Cargo.toml
 
 notifications:

Cargo.toml

@@ -21,6 +21,4 @@ members = ["testcrate"]
 [dependencies]
 futures-await-async-macro = { path = "futures-await-async-macro", version = "0.2.0-alpha" }
 futures-await-await-macro = { path = "futures-await-await-macro", version = "0.2.0-alpha" }
-futures = "0.2.0-alpha"
-futures-stable = "0.2.0-alpha"
-pin-api = "0.1.1"
+futures = { git = "https://github.com/rust-lang-nursery/futures-rs.git", features = ["nightly"] }

README.md

@@ -335,15 +335,22 @@ Otherwise there's a few primary "APIs" provided by this crate:
 
 ### Nightly features
 
-Right now this crate requires two nightly features to be used, and practically
-requires three features to be used to its fullest extent. These three features
+Right now this crate requires three nightly features to be used, and practically
+requires four features to be used to its fullest extent. These four features
 are:
 
 * `#![feature(generators)]` - this is an experimental language feature that has
   yet to be stabilized but is the foundation for the implementation of
-  async/await. The implemented [landed recently][genpr] and progress on
+  async/await. The implementation [landed a while ago][genpr] and progress on
   stabilization can be found on its [tracking issue][gentrack].
 
+* `#![feature(pin)]` - this is another experimental language feature that works
+  together with `generators` to provide support for immovable self-referential
+  generators, without this `async` functions cannot have borrows that exist
+  across the yield points used inside `await!`. The implementation [landed very
+  recently][pinpr] and progress on stabilization can be found on its [tracking
+  issue][pintrack].
+
 * `#![feature(proc_macro)]` - this has also been dubbed "Macros 2.0" and is how
   the `#[async]` attribute is defined in this crate and not the compiler itself.
   We then also take advantage of other macros 2.0 features like importing macros
@@ -357,6 +364,8 @@ are:
   type of future. This feature is tracked at [#34511] and [#42183].
 
 [gentrack]: https://github.com/rust-lang/rust/issues/43122
+[pinpr]: https://github.com/rust-lang/rust/pull/49058
+[pintrack]: https://github.com/rust-lang/rust/issues/49150
 [#38356]: https://github.com/rust-lang/rust/issues/38356
 [#35896]: https://github.com/rust-lang/rust/issues/35896
 [#34511]: https://github.com/rust-lang/rust/issues/34511

futures-await-async-macro/src/lib.rs

@@ -206,7 +206,7 @@ where F: FnOnce(&Type, &[&Lifetime]) -> proc_macro2::TokenStream
     let gen_function = respan(gen_function.into(), &output_span);
     let body_inner = if pinned {
         quote_cs! {
-            #gen_function (#[allow(unused_unsafe)] unsafe { static move || -> #output #gen_body })
+            #gen_function (static move || -> #output #gen_body)
         }
     } else {
         quote_cs! {
@@ -252,14 +252,14 @@ pub fn async(attribute: TokenStream, function: TokenStream) -> TokenStream {
         let output_span = first_last(&output);
         let return_ty = if boxed && !send {
             quote_cs! {
-                ::futures::__rt::PinBox<::futures::__rt::Future<
+                ::futures::__rt::boxed::PinBox<::futures::__rt::Future<
                     Item = <! as ::futures::__rt::IsResult>::Ok,
                     Error = <! as ::futures::__rt::IsResult>::Err,
                 >>
             }
         } else if boxed && send {
             quote_cs! {
-                ::futures::__rt::PinBox<::futures::__rt::Future<
+                ::futures::__rt::boxed::PinBox<::futures::__rt::Future<
                     Item = <! as ::futures::__rt::IsResult>::Ok,
                     Error = <! as ::futures::__rt::IsResult>::Err,
                 > + Send>
@@ -293,14 +293,14 @@ pub fn async_move(attribute: TokenStream, function: TokenStream) -> TokenStream
                 ::futures::__rt::std::boxed::Box<::futures::__rt::Future<
                     Item = <! as ::futures::__rt::IsResult>::Ok,
                     Error = <! as ::futures::__rt::IsResult>::Err,
-                > + ::futures::__rt::pin_api::Unpin + #(#lifetimes +)*>
+                > + ::futures::__rt::std::marker::Unpin + #(#lifetimes +)*>
             }
         } else if boxed && send {
             quote_cs! {
                 ::futures::__rt::std::boxed::Box<::futures::__rt::Future<
                     Item = <! as ::futures::__rt::IsResult>::Ok,
                     Error = <! as ::futures::__rt::IsResult>::Err,
-                > + ::futures::__rt::pin_api::Unpin + Send + #(#lifetimes +)*>
+                > + ::futures::__rt::std::marker::Unpin + Send + #(#lifetimes +)*>
             }
         } else {
             // Dunno why this is buggy, hits weird typecheck errors in tests
@@ -359,7 +359,7 @@ pub fn async_stream(attribute: TokenStream, function: TokenStream) -> TokenStrea
         let output_span = first_last(&output);
         let return_ty = if boxed {
             quote_cs! {
-                ::futures::__rt::PinBox<::futures::__rt::Stream<
+                ::futures::__rt::boxed::PinBox<::futures::__rt::Stream<
                     Item = !,
                     Error = <! as ::futures::__rt::IsResult>::Err,
                 > + #(#lifetimes +)*>
@@ -416,7 +416,7 @@ pub fn async_stream_move(attribute: TokenStream, function: TokenStream) -> Token
                 ::futures::__rt::std::boxed::Box<::futures::__rt::Stream<
                     Item = !,
                     Error = <! as ::futures::__rt::IsResult>::Err,
-                > + ::futures::__rt::pin_api::Unpin + #(#lifetimes +)*>
+                > + ::futures::__rt::std::marker::Unpin + #(#lifetimes +)*>
             }
         } else {
             quote_cs! { impl ::futures::__rt::MyStream<!, !> + #(#lifetimes +)* }
@@ -523,7 +523,7 @@ impl Fold for ExpandAsyncFor {
                 let #pat = {
                     let r = {
                         let pin = unsafe {
-                            ::futures::__rt::pin_api::PinMut::new_unchecked(&mut __stream)
+                            ::futures::__rt::std::mem::Pin::new_unchecked(&mut __stream)
                         };
                         ::futures::__rt::in_ctx(|ctx| ::futures::__rt::StableStream::poll_next(pin, ctx))
                     };

futures-await-await-macro/src/lib.rs

@@ -15,7 +15,7 @@ macro_rules! await {
         loop {
             let poll = {
                 let pin = unsafe {
-                    ::futures::__rt::pin_api::PinMut::new_unchecked(&mut future)
+                    ::futures::__rt::std::mem::Pin::new_unchecked(&mut future)
                 };
                 ::futures::__rt::in_ctx(|ctx| ::futures::__rt::StableFuture::poll(pin, ctx))
             };

src/__rt/future.rs

@@ -36,7 +36,10 @@ impl<T> Future for GenFuture<T>
     fn poll(&mut self, ctx: &mut task::Context) -> Poll<Self::Item, Self::Error> {
         CTX.with(|cell| {
             let _r = Reset::new(ctx, cell);
-            match self.0.resume() {
+            // Because we are controlling the creation of our underlying
+            // generator, we know that this is definitely a movable generator
+            // so calling resume is always safe.
+            match unsafe { self.0.resume() } {
                 GeneratorState::Yielded(Async::Pending)
                     => Ok(Async::Pending),
                 GeneratorState::Yielded(Async::Ready(mu))

src/__rt/mod.rs

@@ -13,10 +13,9 @@ pub use self::pinned_future::*;
 pub use self::pinned_stream::*;
 
 pub use futures::prelude::{Async, Future, Stream};
-pub use stable::{StableFuture, StableStream};
+pub use futures::stable::{StableFuture, StableStream};
 
 pub extern crate std;
-pub extern crate pin_api;
 
 pub use std::ops::Generator;
 

src/__rt/pinned_future.rs

@@ -1,11 +1,11 @@
+use std::marker::Unpin;
+use std::mem::Pin;
 use std::ops::{Generator, GeneratorState};
 
-use __rt::pin_api::{PinMut, Unpin};
-
 use super::{IsResult, Reset, CTX};
 
 use futures::Never;
-use stable::StableFuture;
+use futures::stable::StableFuture;
 use task;
 use prelude::{Poll, Async};
 
@@ -27,11 +27,13 @@ impl<T> StableFuture for GenStableFuture<T>
     type Item = <T::Return as IsResult>::Ok;
     type Error = <T::Return as IsResult>::Err;
 
-    fn poll(mut self: PinMut<Self>, ctx: &mut task::Context) -> Poll<Self::Item, Self::Error> {
+    fn poll(mut self: Pin<Self>, ctx: &mut task::Context) -> Poll<Self::Item, Self::Error> {
         CTX.with(|cell| {
             let _r = Reset::new(ctx, cell);
-            let this: &mut Self = unsafe { PinMut::get_mut(&mut self) };
-            match this.0.resume() {
+            let this: &mut Self = unsafe { Pin::get_mut(&mut self) };
+            // This is an immovable generator, but since we're only accessing
+            // it via a Pin this is safe.
+            match unsafe { this.0.resume() } {
                 GeneratorState::Yielded(Async::Pending)
                     => Ok(Async::Pending),
                 GeneratorState::Yielded(Async::Ready(mu))

src/__rt/pinned_stream.rs

@@ -1,10 +1,10 @@
+use std::mem::Pin;
 use std::ops::{Generator, GeneratorState};
-use std::marker::PhantomData;
+use std::marker::{PhantomData, Unpin};
 
-use __rt::pin_api::{PinMut, Unpin};
 use futures::task;
 use futures::prelude::{Poll, Async};
-use stable::StableStream;
+use futures::stable::StableStream;
 
 use super::{CTX, Reset, IsResult};
 
@@ -38,12 +38,14 @@ impl<U, T> StableStream for GenStableStream<U, T>
     type Item = U;
     type Error = <T::Return as IsResult>::Err;
 
-    fn poll_next(mut self: PinMut<Self>, ctx: &mut task::Context) -> Poll<Option<Self::Item>, Self::Error> {
+    fn poll_next(mut self: Pin<Self>, ctx: &mut task::Context) -> Poll<Option<Self::Item>, Self::Error> {
         CTX.with(|cell| {
             let _r = Reset::new(ctx, cell);
-            let this: &mut Self = unsafe { PinMut::get_mut(&mut self) };
+            let this: &mut Self = unsafe { Pin::get_mut(&mut self) };
             if this.done { return Ok(Async::Ready(None)) }
-            match this.gen.resume() {
+            // This is an immovable generator, but since we're only accessing
+            // it via a Pin this is safe.
+            match unsafe { this.gen.resume() } {
                 GeneratorState::Yielded(Async::Ready(e)) => {
                     Ok(Async::Ready(Some(e)))
                 }

src/__rt/stream.rs

@@ -38,7 +38,10 @@ impl<U, T> Stream for GenStream<U, T>
         CTX.with(|cell| {
             let _r = Reset::new(ctx, cell);
             if self.done { return Ok(Async::Ready(None)) }
-            match self.gen.resume() {
+            // Because we are controlling the creation of our underlying
+            // generator, we know that this is definitely a movable generator
+            // so calling resume is always safe.
+            match unsafe { self.gen.resume() } {
                 GeneratorState::Yielded(Async::Ready(e)) => {
                     Ok(Async::Ready(Some(e)))
                 }

src/lib.rs

@@ -18,11 +18,11 @@
 #![feature(on_unimplemented)]
 #![feature(arbitrary_self_types)]
 #![feature(optin_builtin_traits)]
+#![feature(pin)]
 
 extern crate futures_await_async_macro as async_macro;
 extern crate futures_await_await_macro as await_macro;
 extern crate futures;
-pub extern crate futures_stable as stable;
 
 pub use futures::*;
 

testcrate/ui/bad-return-type.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;
 

testcrate/ui/bad-return-type.stderr

@@ -86,5 +86,5 @@ error[E0308]: mismatched types
 
 error: aborting due to 7 previous errors
 
-You've got a few errors: E0308, E0907
-If you want more information on an error, try using "rustc --explain E0308"
+Some errors occurred: E0308, E0907.
+For more information about an error, try `rustc --explain E0308`.

testcrate/ui/forget-ok.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;
 

testcrate/ui/forget-ok.stderr

@@ -22,4 +22,4 @@ error[E0308]: mismatched types
 
 error: aborting due to 2 previous errors
 
-If you want more information on this error, try using "rustc --explain E0308"
+For more information about this error, try `rustc --explain E0308`.

testcrate/ui/missing-item.rs

@@ -1,5 +1,5 @@
 #![allow(warnings)]
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;
 

testcrate/ui/missing-item.stderr

@@ -6,3 +6,5 @@ error: custom attribute panicked
   |
   = help: message: #[async_stream] requires item type to be specified
 
+error: aborting due to previous error
+

testcrate/ui/move-captured-variable.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;
 

testcrate/ui/move-captured-variable.stderr

@@ -11,4 +11,4 @@ error[E0507]: cannot move out of captured outer variable in an `FnMut` closure
 
 error: aborting due to previous error
 
-If you want more information on this error, try using "rustc --explain E0507"
+For more information about this error, try `rustc --explain E0507`.

testcrate/ui/not-a-result.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;
 

testcrate/ui/not-a-result.stderr

@@ -58,4 +58,4 @@ error[E0277]: the trait bound `u32: futures::__rt::IsResult` is not satisfied
 
 error: aborting due to 6 previous errors
 
-If you want more information on this error, try using "rustc --explain E0277"
+For more information about this error, try `rustc --explain E0277`.

testcrate/ui/type_error.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;
 

testcrate/ui/type_error.stderr

@@ -9,4 +9,4 @@ error[E0308]: mismatched types
 
 error: aborting due to previous error
 
-If you want more information on this error, try using "rustc --explain E0308"
+For more information about this error, try `rustc --explain E0308`.

testcrate/ui/unresolved-type.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;
 

testcrate/ui/unresolved-type.stderr

@@ -30,5 +30,5 @@ note: the type is part of the generator because of this `yield`
 
 error: aborting due to 3 previous errors
 
-You've got a few errors: E0412, E0907
-If you want more information on an error, try using "rustc --explain E0412"
+Some errors occurred: E0412, E0907.
+For more information about an error, try `rustc --explain E0412`.

tests/elisions.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators, underscore_lifetimes)]
+#![feature(proc_macro, conservative_impl_trait, generators, underscore_lifetimes, pin)]
 
 extern crate futures_await as futures;
 

tests/pinned.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro, conservative_impl_trait, generators, underscore_lifetimes)]
+#![feature(proc_macro, conservative_impl_trait, generators, underscore_lifetimes, pin)]
 
 extern crate futures_await as futures;
 

tests/smoke.rs

@@ -3,7 +3,7 @@
 //! This is mostly a test f r this repository itself, not necessarily serving
 //! much more purpose than that.
 
-#![feature(proc_macro, conservative_impl_trait, generators)]
+#![feature(proc_macro, conservative_impl_trait, generators, pin)]
 
 extern crate futures_await as futures;