From ad42b0098183262b33b18d45e471cd2ef3594e60 Mon Sep 17 00:00:00 2001
From: Pierre Krieger <pierre.krieger1708@gmail.com>
Date: Tue, 10 Dec 2019 11:46:30 +0100
Subject: [PATCH 1/2] Cleanups in libp2p-core in stable-futures branch

---
 core/Cargo.toml               |   1 +
 core/src/either.rs            | 196 ++++++++++++++++------------------
 core/src/lib.rs               |   2 -
 core/src/transport/choice.rs  |   6 --
 core/src/transport/map.rs     |  33 +++---
 core/src/transport/map_err.rs |  51 ++++-----
 core/src/transport/timeout.rs |  28 +++--
 core/src/upgrade/map.rs       |  35 +++---
 core/src/upgrade/mod.rs       |   2 -
 core/src/upgrade/select.rs    |   2 -
 10 files changed, 161 insertions(+), 195 deletions(-)

diff --git a/core/Cargo.toml b/core/Cargo.toml
index 8884097cbc2..2e1b18cb52f 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -25,6 +25,7 @@ multiaddr = { package = "parity-multiaddr", version = "0.6.0", path = "../misc/m
 multihash = { package = "parity-multihash", version = "0.2.0", path = "../misc/multihash" }
 multistream-select = { version = "0.6.0", path = "../misc/multistream-select" }
 parking_lot = "0.9.0"
+pin-project = "0.4.6"
 protobuf = "2.8"
 quick-error = "1.2"
 rand = "0.7"
diff --git a/core/src/either.rs b/core/src/either.rs
index f1b69e41bc6..0d0fc794a7b 100644
--- a/core/src/either.rs
+++ b/core/src/either.rs
@@ -20,7 +20,8 @@
 
 use crate::{muxing::StreamMuxer, ProtocolName, transport::ListenerEvent};
 use futures::prelude::*;
-use std::{fmt, io::{Error as IoError, Read, Write}, pin::Pin, task::Context, task::Poll};
+use pin_project::{pin_project, project};
+use std::{fmt, io::{Error as IoError}, pin::Pin, task::Context, task::Poll};
 
 #[derive(Debug, Copy, Clone)]
 pub enum EitherError<A, B> {
@@ -56,99 +57,75 @@ where
 
 /// Implements `AsyncRead` and `AsyncWrite` and dispatches all method calls to
 /// either `First` or `Second`.
+#[pin_project]
 #[derive(Debug, Copy, Clone)]
 pub enum EitherOutput<A, B> {
-    First(A),
-    Second(B),
+    First(#[pin] A),
+    Second(#[pin] B),
 }
 
 impl<A, B> AsyncRead for EitherOutput<A, B>
 where
-    A: AsyncRead + Unpin,
-    B: AsyncRead + Unpin,
+    A: AsyncRead,
+    B: AsyncRead,
 {
-    fn poll_read(mut self: Pin<&mut Self>, cx: &mut Context, buf: &mut [u8]) -> Poll<Result<usize, IoError>> {
-        match &mut *self {
-            EitherOutput::First(a) => AsyncRead::poll_read(Pin::new(a), cx, buf),
-            EitherOutput::Second(b) => AsyncRead::poll_read(Pin::new(b), cx, buf),
-        }
-    }
-}
-
-// TODO: remove?
-impl<A, B> Read for EitherOutput<A, B>
-where
-    A: Read,
-    B: Read,
-{
-    fn read(&mut self, buf: &mut [u8]) -> Result<usize, IoError> {
-        match self {
-            EitherOutput::First(a) => a.read(buf),
-            EitherOutput::Second(b) => b.read(buf),
+    #[project]
+    fn poll_read(self: Pin<&mut Self>, cx: &mut Context, buf: &mut [u8]) -> Poll<Result<usize, IoError>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => AsyncRead::poll_read(a, cx, buf),
+            EitherOutput::Second(b) => AsyncRead::poll_read(b, cx, buf),
         }
     }
 }
 
 impl<A, B> AsyncWrite for EitherOutput<A, B>
 where
-    A: AsyncWrite + Unpin,
-    B: AsyncWrite + Unpin,
+    A: AsyncWrite,
+    B: AsyncWrite,
 {
-    fn poll_write(mut self: Pin<&mut Self>, cx: &mut Context, buf: &[u8]) -> Poll<Result<usize, IoError>> {
-        match &mut *self {
-            EitherOutput::First(a) => AsyncWrite::poll_write(Pin::new(a), cx, buf),
-            EitherOutput::Second(b) => AsyncWrite::poll_write(Pin::new(b), cx, buf),
-        }
-    }
-
-    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
-        match &mut *self {
-            EitherOutput::First(a) => AsyncWrite::poll_flush(Pin::new(a), cx),
-            EitherOutput::Second(b) => AsyncWrite::poll_flush(Pin::new(b), cx),
+    #[project]
+    fn poll_write(self: Pin<&mut Self>, cx: &mut Context, buf: &[u8]) -> Poll<Result<usize, IoError>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => AsyncWrite::poll_write(a, cx, buf),
+            EitherOutput::Second(b) => AsyncWrite::poll_write(b, cx, buf),
         }
     }
 
-    fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
-        match &mut *self {
-            EitherOutput::First(a) => AsyncWrite::poll_close(Pin::new(a), cx),
-            EitherOutput::Second(b) => AsyncWrite::poll_close(Pin::new(b), cx),
+    #[project]
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => AsyncWrite::poll_flush(a, cx),
+            EitherOutput::Second(b) => AsyncWrite::poll_flush(b, cx),
         }
     }
-}
 
-// TODO: remove?
-impl<A, B> Write for EitherOutput<A, B>
-where
-    A: Write,
-    B: Write,
-{
-    fn write(&mut self, buf: &[u8]) -> Result<usize, IoError> {
-        match self {
-            EitherOutput::First(a) => a.write(buf),
-            EitherOutput::Second(b) => b.write(buf),
-        }
-    }
-
-    fn flush(&mut self) -> Result<(), IoError> {
-        match self {
-            EitherOutput::First(a) => a.flush(),
-            EitherOutput::Second(b) => b.flush(),
+    #[project]
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => AsyncWrite::poll_close(a, cx),
+            EitherOutput::Second(b) => AsyncWrite::poll_close(b, cx),
         }
     }
 }
 
 impl<A, B, I> Stream for EitherOutput<A, B>
 where
-    A: TryStream<Ok = I> + Unpin,
-    B: TryStream<Ok = I> + Unpin,
+    A: TryStream<Ok = I>,
+    B: TryStream<Ok = I>,
 {
     type Item = Result<I, EitherError<A::Error, B::Error>>;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
-        match &mut *self {
-            EitherOutput::First(a) => TryStream::try_poll_next(Pin::new(a), cx)
+    #[project]
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => TryStream::try_poll_next(a, cx)
                 .map(|v| v.map(|r| r.map_err(EitherError::A))),
-            EitherOutput::Second(b) => TryStream::try_poll_next(Pin::new(b), cx)
+            EitherOutput::Second(b) => TryStream::try_poll_next(b, cx)
                 .map(|v| v.map(|r| r.map_err(EitherError::B))),
         }
     }
@@ -161,31 +138,39 @@ where
 {
     type Error = EitherError<A::Error, B::Error>;
 
-    fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
-        match &mut *self {
-            EitherOutput::First(a) => Sink::poll_ready(Pin::new(a), cx).map_err(EitherError::A),
-            EitherOutput::Second(b) => Sink::poll_ready(Pin::new(b), cx).map_err(EitherError::B),
+    #[project]
+    fn poll_ready(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => Sink::poll_ready(a, cx).map_err(EitherError::A),
+            EitherOutput::Second(b) => Sink::poll_ready(b, cx).map_err(EitherError::B),
         }
     }
 
-    fn start_send(mut self: Pin<&mut Self>, item: I) -> Result<(), Self::Error> {
-        match &mut *self {
-            EitherOutput::First(a) => Sink::start_send(Pin::new(a), item).map_err(EitherError::A),
-            EitherOutput::Second(b) => Sink::start_send(Pin::new(b), item).map_err(EitherError::B),
+    #[project]
+    fn start_send(self: Pin<&mut Self>, item: I) -> Result<(), Self::Error> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => Sink::start_send(a, item).map_err(EitherError::A),
+            EitherOutput::Second(b) => Sink::start_send(b, item).map_err(EitherError::B),
         }
     }
 
-    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
-        match &mut *self {
-            EitherOutput::First(a) => Sink::poll_flush(Pin::new(a), cx).map_err(EitherError::A),
-            EitherOutput::Second(b) => Sink::poll_flush(Pin::new(b), cx).map_err(EitherError::B),
+    #[project]
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => Sink::poll_flush(a, cx).map_err(EitherError::A),
+            EitherOutput::Second(b) => Sink::poll_flush(b, cx).map_err(EitherError::B),
         }
     }
 
-    fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
-        match &mut *self {
-            EitherOutput::First(a) => Sink::poll_close(Pin::new(a), cx).map_err(EitherError::A),
-            EitherOutput::Second(b) => Sink::poll_close(Pin::new(b), cx).map_err(EitherError::B),
+    #[project]
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
+        #[project]
+        match self.project() {
+            EitherOutput::First(a) => Sink::poll_close(a, cx).map_err(EitherError::A),
+            EitherOutput::Second(b) => Sink::poll_close(b, cx).map_err(EitherError::B),
         }
     }
 }
@@ -337,29 +322,32 @@ pub enum EitherOutbound<A: StreamMuxer, B: StreamMuxer> {
 }
 
 /// Implements `Stream` and dispatches all method calls to either `First` or `Second`.
+#[pin_project]
 #[derive(Debug, Copy, Clone)]
 #[must_use = "futures do nothing unless polled"]
 pub enum EitherListenStream<A, B> {
-    First(A),
-    Second(B),
+    First(#[pin] A),
+    Second(#[pin] B),
 }
 
 impl<AStream, BStream, AInner, BInner> Stream for EitherListenStream<AStream, BStream>
 where
-    AStream: TryStream<Ok = ListenerEvent<AInner>> + Unpin,
-    BStream: TryStream<Ok = ListenerEvent<BInner>> + Unpin,
+    AStream: TryStream<Ok = ListenerEvent<AInner>>,
+    BStream: TryStream<Ok = ListenerEvent<BInner>>,
 {
     type Item = Result<ListenerEvent<EitherFuture<AInner, BInner>>, EitherError<AStream::Error, BStream::Error>>;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
-        match &mut *self {
-            EitherListenStream::First(a) => match TryStream::try_poll_next(Pin::new(a), cx) {
+    #[project]
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        #[project]
+        match self.project() {
+            EitherListenStream::First(a) => match TryStream::try_poll_next(a, cx) {
                 Poll::Pending => Poll::Pending,
                 Poll::Ready(None) => Poll::Ready(None),
                 Poll::Ready(Some(Ok(le))) => Poll::Ready(Some(Ok(le.map(EitherFuture::First)))),
                 Poll::Ready(Some(Err(err))) => Poll::Ready(Some(Err(EitherError::A(err)))),
             },
-            EitherListenStream::Second(a) => match TryStream::try_poll_next(Pin::new(a), cx) {
+            EitherListenStream::Second(a) => match TryStream::try_poll_next(a, cx) {
                 Poll::Pending => Poll::Pending,
                 Poll::Ready(None) => Poll::Ready(None),
                 Poll::Ready(Some(Ok(le))) => Poll::Ready(Some(Ok(le.map(EitherFuture::Second)))),
@@ -370,33 +358,37 @@ where
 }
 
 /// Implements `Future` and dispatches all method calls to either `First` or `Second`.
+#[pin_project]
 #[derive(Debug, Copy, Clone)]
 #[must_use = "futures do nothing unless polled"]
 pub enum EitherFuture<A, B> {
-    First(A),
-    Second(B),
+    First(#[pin] A),
+    Second(#[pin] B),
 }
 
 impl<AFuture, BFuture, AInner, BInner> Future for EitherFuture<AFuture, BFuture>
 where
-    AFuture: TryFuture<Ok = AInner> + Unpin,
-    BFuture: TryFuture<Ok = BInner> + Unpin,
+    AFuture: TryFuture<Ok = AInner>,
+    BFuture: TryFuture<Ok = BInner>,
 {
     type Output = Result<EitherOutput<AInner, BInner>, EitherError<AFuture::Error, BFuture::Error>>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        match &mut *self {
-            EitherFuture::First(a) => TryFuture::try_poll(Pin::new(a), cx)
+    #[project]
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        #[project]
+        match self.project() {
+            EitherFuture::First(a) => TryFuture::try_poll(a, cx)
                 .map_ok(EitherOutput::First).map_err(EitherError::A),
-            EitherFuture::Second(a) => TryFuture::try_poll(Pin::new(a), cx)
+            EitherFuture::Second(a) => TryFuture::try_poll(a, cx)
                 .map_ok(EitherOutput::Second).map_err(EitherError::B),
         }
     }
 }
 
+#[pin_project]
 #[derive(Debug, Copy, Clone)]
 #[must_use = "futures do nothing unless polled"]
-pub enum EitherFuture2<A, B> { A(A), B(B) }
+pub enum EitherFuture2<A, B> { A(#[pin] A), B(#[pin] B) }
 
 impl<AFut, BFut, AItem, BItem, AError, BError> Future for EitherFuture2<AFut, BFut>
 where
@@ -405,11 +397,13 @@ where
 {
     type Output = Result<EitherOutput<AItem, BItem>, EitherError<AError, BError>>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        match &mut *self {
-            EitherFuture2::A(a) => TryFuture::try_poll(Pin::new(a), cx)
+    #[project]
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        #[project]
+        match self.project() {
+            EitherFuture2::A(a) => TryFuture::try_poll(a, cx)
                 .map_ok(EitherOutput::First).map_err(EitherError::A),
-            EitherFuture2::B(a) => TryFuture::try_poll(Pin::new(a), cx)
+            EitherFuture2::B(a) => TryFuture::try_poll(a, cx)
                 .map_ok(EitherOutput::Second).map_err(EitherError::B),
         }
     }
diff --git a/core/src/lib.rs b/core/src/lib.rs
index 471e928f1db..f6af9c10dc8 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -18,8 +18,6 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-#![cfg_attr(feature = "async-await", feature(async_await))]
-
 //! Transports, upgrades, multiplexing and node handling of *libp2p*.
 //!
 //! The main concepts of libp2p-core are:
diff --git a/core/src/transport/choice.rs b/core/src/transport/choice.rs
index c3bfc15d1f0..c6593912761 100644
--- a/core/src/transport/choice.rs
+++ b/core/src/transport/choice.rs
@@ -35,13 +35,7 @@ impl<A, B> OrTransport<A, B> {
 impl<A, B> Transport for OrTransport<A, B>
 where
     B: Transport,
-    B::Dial: Unpin,
-    B::Listener: Unpin,
-    B::ListenerUpgrade: Unpin,
     A: Transport,
-    A::Dial: Unpin,
-    A::Listener: Unpin,
-    A::ListenerUpgrade: Unpin,
 {
     type Output = EitherOutput<A::Output, B::Output>;
     type Error = EitherError<A::Error, B::Error>;
diff --git a/core/src/transport/map.rs b/core/src/transport/map.rs
index 7652e89232a..33772cf2b0e 100644
--- a/core/src/transport/map.rs
+++ b/core/src/transport/map.rs
@@ -39,9 +39,6 @@ impl<T, F> Map<T, F> {
 impl<T, F, D> Transport for Map<T, F>
 where
     T: Transport,
-    T::Dial: Unpin,
-    T::Listener: Unpin,
-    T::ListenerUpgrade: Unpin,
     F: FnOnce(T::Output, ConnectedPoint) -> D + Clone
 {
     type Output = D;
@@ -65,22 +62,21 @@ where
 /// Custom `Stream` implementation to avoid boxing.
 ///
 /// Maps a function over every stream item.
+#[pin_project::pin_project]
 #[derive(Clone, Debug)]
-pub struct MapStream<T, F> { stream: T, fun: F }
-
-impl<T, F> Unpin for MapStream<T, F> {
-}
+pub struct MapStream<T, F> { #[pin] stream: T, fun: F }
 
 impl<T, F, A, B, X> Stream for MapStream<T, F>
 where
-    T: TryStream<Ok = ListenerEvent<X>> + Unpin,
+    T: TryStream<Ok = ListenerEvent<X>>,
     X: TryFuture<Ok = A>,
     F: FnOnce(A, ConnectedPoint) -> B + Clone
 {
     type Item = Result<ListenerEvent<MapFuture<X, F>>, T::Error>;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
-        match TryStream::try_poll_next(Pin::new(&mut self.stream), cx) {
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        let this = self.project();
+        match TryStream::try_poll_next(this.stream, cx) {
             Poll::Ready(Some(Ok(event))) => {
                 let event = match event {
                     ListenerEvent::Upgrade { upgrade, local_addr, remote_addr } => {
@@ -91,7 +87,7 @@ where
                         ListenerEvent::Upgrade {
                             upgrade: MapFuture {
                                 inner: upgrade,
-                                args: Some((self.fun.clone(), point))
+                                args: Some((this.fun.clone(), point))
                             },
                             local_addr,
                             remote_addr
@@ -112,30 +108,29 @@ where
 /// Custom `Future` to avoid boxing.
 ///
 /// Applies a function to the inner future's result.
+#[pin_project::pin_project]
 #[derive(Clone, Debug)]
 pub struct MapFuture<T, F> {
+    #[pin]
     inner: T,
     args: Option<(F, ConnectedPoint)>
 }
 
-impl<T, F> Unpin for MapFuture<T, F> {
-}
-
 impl<T, A, F, B> Future for MapFuture<T, F>
 where
-    T: TryFuture<Ok = A> + Unpin,
+    T: TryFuture<Ok = A>,
     F: FnOnce(A, ConnectedPoint) -> B
 {
     type Output = Result<B, T::Error>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        let item = match TryFuture::try_poll(Pin::new(&mut self.inner), cx) {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        let this = self.project();
+        let item = match TryFuture::try_poll(this.inner, cx) {
             Poll::Pending => return Poll::Pending,
             Poll::Ready(Ok(v)) => v,
             Poll::Ready(Err(err)) => return Poll::Ready(Err(err)),
         };
-        let (f, a) = self.args.take().expect("MapFuture has already finished.");
+        let (f, a) = this.args.take().expect("MapFuture has already finished.");
         Poll::Ready(Ok(f(item, a)))
     }
 }
-
diff --git a/core/src/transport/map_err.rs b/core/src/transport/map_err.rs
index 36f48209b5d..ba36114682b 100644
--- a/core/src/transport/map_err.rs
+++ b/core/src/transport/map_err.rs
@@ -40,9 +40,6 @@ impl<T, F> MapErr<T, F> {
 impl<T, F, TErr> Transport for MapErr<T, F>
 where
     T: Transport,
-    T::Dial: Unpin,
-    T::Listener: Unpin,
-    T::ListenerUpgrade: Unpin,
     F: FnOnce(T::Error) -> TErr + Clone,
     TErr: error::Error,
 {
@@ -70,67 +67,62 @@ where
 }
 
 /// Listening stream for `MapErr`.
+#[pin_project::pin_project]
 pub struct MapErrListener<T: Transport, F> {
+    #[pin]
     inner: T::Listener,
     map: F,
 }
 
-impl<T, F> Unpin for MapErrListener<T, F>
-    where T: Transport
-{
-}
-
 impl<T, F, TErr> Stream for MapErrListener<T, F>
 where
     T: Transport,
-    T::Listener: Unpin,
     F: FnOnce(T::Error) -> TErr + Clone,
     TErr: error::Error,
 {
     type Item = Result<ListenerEvent<MapErrListenerUpgrade<T, F>>, TErr>;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
-        match TryStream::try_poll_next(Pin::new(&mut self.inner), cx) {
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        let this = self.project();
+        match TryStream::try_poll_next(this.inner, cx) {
             Poll::Ready(Some(Ok(event))) => {
+                let map = &*this.map;
                 let event = event.map(move |value| {
                     MapErrListenerUpgrade {
                         inner: value,
-                        map: Some(self.map.clone())
+                        map: Some(map.clone())
                     }
                 });
                 Poll::Ready(Some(Ok(event)))
             }
             Poll::Ready(None) => Poll::Ready(None),
             Poll::Pending => Poll::Pending,
-            Poll::Ready(Some(Err(err))) => Poll::Ready(Some(Err((self.map.clone())(err)))),
+            Poll::Ready(Some(Err(err))) => Poll::Ready(Some(Err((this.map.clone())(err)))),
         }
     }
 }
 
 /// Listening upgrade future for `MapErr`.
+#[pin_project::pin_project]
 pub struct MapErrListenerUpgrade<T: Transport, F> {
+    #[pin]
     inner: T::ListenerUpgrade,
     map: Option<F>,
 }
 
-impl<T, F> Unpin for MapErrListenerUpgrade<T, F>
-    where T: Transport
-{
-}
-
 impl<T, F, TErr> Future for MapErrListenerUpgrade<T, F>
 where T: Transport,
-    T::ListenerUpgrade: Unpin,
     F: FnOnce(T::Error) -> TErr,
 {
     type Output = Result<T::Output, TErr>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        match Future::poll(Pin::new(&mut self.inner), cx) {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        let this = self.project();
+        match Future::poll(this.inner, cx) {
             Poll::Ready(Ok(value)) => Poll::Ready(Ok(value)),
             Poll::Pending => Poll::Pending,
             Poll::Ready(Err(err)) => {
-                let map = self.map.take().expect("poll() called again after error");
+                let map = this.map.take().expect("poll() called again after error");
                 Poll::Ready(Err(map(err)))
             }
         }
@@ -138,30 +130,27 @@ where T: Transport,
 }
 
 /// Dialing future for `MapErr`.
+#[pin_project::pin_project]
 pub struct MapErrDial<T: Transport, F> {
+    #[pin]
     inner: T::Dial,
     map: Option<F>,
 }
 
-impl<T, F> Unpin for MapErrDial<T, F>
-    where T: Transport
-{
-}
-
 impl<T, F, TErr> Future for MapErrDial<T, F>
 where
     T: Transport,
-    T::Dial: Unpin,
     F: FnOnce(T::Error) -> TErr,
 {
     type Output = Result<T::Output, TErr>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        match Future::poll(Pin::new(&mut self.inner), cx) {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        let this = self.project();
+        match Future::poll(this.inner, cx) {
             Poll::Ready(Ok(value)) => Poll::Ready(Ok(value)),
             Poll::Pending => Poll::Pending,
             Poll::Ready(Err(err)) => {
-                let map = self.map.take().expect("poll() called again after error");
+                let map = this.map.take().expect("poll() called again after error");
                 Poll::Ready(Err(map(err)))
             }
         }
diff --git a/core/src/transport/timeout.rs b/core/src/transport/timeout.rs
index c254d24186f..15fcf855ac6 100644
--- a/core/src/transport/timeout.rs
+++ b/core/src/transport/timeout.rs
@@ -74,9 +74,6 @@ impl<InnerTrans> Transport for TransportTimeout<InnerTrans>
 where
     InnerTrans: Transport,
     InnerTrans::Error: 'static,
-    InnerTrans::Dial: Unpin,
-    InnerTrans::Listener: Unpin,
-    InnerTrans::ListenerUpgrade: Unpin,
 {
     type Output = InnerTrans::Output;
     type Error = TransportTimeoutError<InnerTrans::Error>;
@@ -108,29 +105,34 @@ where
 
 // TODO: can be removed and replaced with an `impl Stream` once impl Trait is fully stable
 //       in Rust (https://github.com/rust-lang/rust/issues/34511)
+#[pin_project::pin_project]
 pub struct TimeoutListener<InnerStream> {
+    #[pin]
     inner: InnerStream,
     timeout: Duration,
 }
 
 impl<InnerStream, O> Stream for TimeoutListener<InnerStream>
 where
-    InnerStream: TryStream<Ok = ListenerEvent<O>> + Unpin
+    InnerStream: TryStream<Ok = ListenerEvent<O>>,
 {
     type Item = Result<ListenerEvent<Timeout<O>>, TransportTimeoutError<InnerStream::Error>>;
 
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
-        let poll_out = match TryStream::try_poll_next(Pin::new(&mut self.inner), cx) {
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        let this = self.project();
+
+        let poll_out = match TryStream::try_poll_next(this.inner, cx) {
             Poll::Ready(Some(Err(err))) => return Poll::Ready(Some(Err(TransportTimeoutError::Other(err)))),
             Poll::Ready(Some(Ok(v))) => v,
             Poll::Ready(None) => return Poll::Ready(None),
             Poll::Pending => return Poll::Pending,
         };
 
+        let timeout = *this.timeout;
         let event = poll_out.map(move |inner_fut| {
             Timeout {
                 inner: inner_fut,
-                timer: Delay::new(self.timeout),
+                timer: Delay::new(timeout),
             }
         });
 
@@ -142,31 +144,35 @@ where
 /// `TransportTimeoutError<Err>`.
 // TODO: can be replaced with `impl Future` once `impl Trait` are fully stable in Rust
 //       (https://github.com/rust-lang/rust/issues/34511)
+#[pin_project::pin_project]
 #[must_use = "futures do nothing unless polled"]
 pub struct Timeout<InnerFut> {
+    #[pin]
     inner: InnerFut,
     timer: Delay,
 }
 
 impl<InnerFut> Future for Timeout<InnerFut>
 where
-    InnerFut: TryFuture + Unpin,
+    InnerFut: TryFuture,
 {
     type Output = Result<InnerFut::Ok, TransportTimeoutError<InnerFut::Error>>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
         // It is debatable whether we should poll the inner future first or the timer first.
         // For example, if you start dialing with a timeout of 10 seconds, then after 15 seconds
         // the dialing succeeds on the wire, then after 20 seconds you poll, then depending on
         // which gets polled first, the outcome will be success or failure.
 
-        match TryFuture::try_poll(Pin::new(&mut self.inner), cx) {
+        let mut this = self.project();
+
+        match TryFuture::try_poll(this.inner, cx) {
             Poll::Pending => {},
             Poll::Ready(Ok(v)) => return Poll::Ready(Ok(v)),
             Poll::Ready(Err(err)) => return Poll::Ready(Err(TransportTimeoutError::Other(err))),
         }
 
-        match TryFuture::try_poll(Pin::new(&mut self.timer), cx) {
+        match TryFuture::try_poll(Pin::new(&mut this.timer), cx) {
             Poll::Pending => Poll::Pending,
             Poll::Ready(Ok(())) => Poll::Ready(Err(TransportTimeoutError::Timeout)),
             Poll::Ready(Err(err)) => Poll::Ready(Err(TransportTimeoutError::TimerError(err))),
diff --git a/core/src/upgrade/map.rs b/core/src/upgrade/map.rs
index ebbd9a246c5..50da58d97dd 100644
--- a/core/src/upgrade/map.rs
+++ b/core/src/upgrade/map.rs
@@ -48,7 +48,6 @@ where
 impl<C, U, F, T> InboundUpgrade<C> for MapInboundUpgrade<U, F>
 where
     U: InboundUpgrade<C>,
-    U::Future: Unpin,
     F: FnOnce(U::Output) -> T
 {
     type Output = T;
@@ -66,7 +65,6 @@ where
 impl<C, U, F> OutboundUpgrade<C> for MapInboundUpgrade<U, F>
 where
     U: OutboundUpgrade<C>,
-    U::Future: Unpin,
 {
     type Output = U::Output;
     type Error = U::Error;
@@ -102,7 +100,6 @@ where
 impl<C, U, F> InboundUpgrade<C> for MapOutboundUpgrade<U, F>
 where
     U: InboundUpgrade<C>,
-    U::Future: Unpin,
 {
     type Output = U::Output;
     type Error = U::Error;
@@ -116,7 +113,6 @@ where
 impl<C, U, F, T> OutboundUpgrade<C> for MapOutboundUpgrade<U, F>
 where
     U: OutboundUpgrade<C>,
-    U::Future: Unpin,
     F: FnOnce(U::Output) -> T
 {
     type Output = T;
@@ -156,7 +152,6 @@ where
 impl<C, U, F, T> InboundUpgrade<C> for MapInboundUpgradeErr<U, F>
 where
     U: InboundUpgrade<C>,
-    U::Future: Unpin,
     F: FnOnce(U::Error) -> T
 {
     type Output = U::Output;
@@ -174,7 +169,6 @@ where
 impl<C, U, F> OutboundUpgrade<C> for MapInboundUpgradeErr<U, F>
 where
     U: OutboundUpgrade<C>,
-    U::Future: Unpin,
 {
     type Output = U::Output;
     type Error = U::Error;
@@ -210,7 +204,6 @@ where
 impl<C, U, F, T> OutboundUpgrade<C> for MapOutboundUpgradeErr<U, F>
 where
     U: OutboundUpgrade<C>,
-    U::Future: Unpin,
     F: FnOnce(U::Error) -> T
 {
     type Output = U::Output;
@@ -238,54 +231,54 @@ where
     }
 }
 
+#[pin_project::pin_project]
 pub struct MapFuture<TInnerFut, TMap> {
+    #[pin]
     inner: TInnerFut,
     map: Option<TMap>,
 }
 
-impl<TInnerFut, TMap> Unpin for MapFuture<TInnerFut, TMap> {
-}
-
 impl<TInnerFut, TIn, TMap, TOut> Future for MapFuture<TInnerFut, TMap>
 where
-    TInnerFut: TryFuture<Ok = TIn> + Unpin,
+    TInnerFut: TryFuture<Ok = TIn>,
     TMap: FnOnce(TIn) -> TOut,
 {
     type Output = Result<TOut, TInnerFut::Error>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        let item = match TryFuture::try_poll(Pin::new(&mut self.inner), cx) {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        let this = self.project();
+        let item = match TryFuture::try_poll(this.inner, cx) {
             Poll::Ready(Ok(v)) => v,
             Poll::Ready(Err(err)) => return Poll::Ready(Err(err)),
             Poll::Pending => return Poll::Pending,
         };
 
-        let map = self.map.take().expect("Future has already finished");
+        let map = this.map.take().expect("Future has already finished");
         Poll::Ready(Ok(map(item)))
     }
 }
 
+#[pin_project::pin_project]
 pub struct MapErrFuture<T, F> {
+    #[pin]
     fut: T,
     fun: Option<F>,
 }
 
-impl<T, F> Unpin for MapErrFuture<T, F> {
-}
-
 impl<T, E, F, A> Future for MapErrFuture<T, F>
 where
-    T: TryFuture<Error = E> + Unpin,
+    T: TryFuture<Error = E>,
     F: FnOnce(E) -> A,
 {
     type Output = Result<T::Ok, A>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
-        match TryFuture::try_poll(Pin::new(&mut self.fut), cx) {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
+        let this = self.project();
+        match TryFuture::try_poll(this.fut, cx) {
             Poll::Pending => Poll::Pending,
             Poll::Ready(Ok(x)) => Poll::Ready(Ok(x)),
             Poll::Ready(Err(e)) => {
-                let f = self.fun.take().expect("Future has not resolved yet");
+                let f = this.fun.take().expect("Future has not resolved yet");
                 Poll::Ready(Err(f(e)))
             }
         }
diff --git a/core/src/upgrade/mod.rs b/core/src/upgrade/mod.rs
index e2043c5ad6b..b0babe7c450 100644
--- a/core/src/upgrade/mod.rs
+++ b/core/src/upgrade/mod.rs
@@ -144,7 +144,6 @@ pub trait InboundUpgrade<C>: UpgradeInfo {
     /// Possible error during the handshake.
     type Error;
     /// Future that performs the handshake with the remote.
-    // TODO: remove Unpin
     type Future: Future<Output = Result<Self::Output, Self::Error>> + Unpin;
 
     /// After we have determined that the remote supports one of the protocols we support, this
@@ -185,7 +184,6 @@ pub trait OutboundUpgrade<C>: UpgradeInfo {
     /// Possible error during the handshake.
     type Error;
     /// Future that performs the handshake with the remote.
-    // TODO: remove Unpin
     type Future: Future<Output = Result<Self::Output, Self::Error>> + Unpin;
 
     /// After we have determined that the remote supports one of the protocols we support, this
diff --git a/core/src/upgrade/select.rs b/core/src/upgrade/select.rs
index 8adcbabcebf..a8ee6504de7 100644
--- a/core/src/upgrade/select.rs
+++ b/core/src/upgrade/select.rs
@@ -59,9 +59,7 @@ where
 impl<C, A, B, TA, TB, EA, EB> InboundUpgrade<C> for SelectUpgrade<A, B>
 where
     A: InboundUpgrade<C, Output = TA, Error = EA>,
-    <A as InboundUpgrade<C>>::Future: Unpin,
     B: InboundUpgrade<C, Output = TB, Error = EB>,
-    <B as InboundUpgrade<C>>::Future: Unpin,
 {
     type Output = EitherOutput<TA, TB>;
     type Error = EitherError<EA, EB>;

From d738f4158f66590991249ea643fc75357df80e39 Mon Sep 17 00:00:00 2001
From: Pierre Krieger <pierre.krieger1708@gmail.com>
Date: Tue, 10 Dec 2019 13:40:40 +0100
Subject: [PATCH 2/2] More work

---
 core/src/upgrade/either.rs | 4 ----
 core/src/upgrade/select.rs | 2 --
 2 files changed, 6 deletions(-)

diff --git a/core/src/upgrade/either.rs b/core/src/upgrade/either.rs
index 6eb99bb3313..9e6d07421ea 100644
--- a/core/src/upgrade/either.rs
+++ b/core/src/upgrade/either.rs
@@ -50,9 +50,7 @@ where
 impl<C, A, B, TA, TB, EA, EB> InboundUpgrade<C> for EitherUpgrade<A, B>
 where
     A: InboundUpgrade<C, Output = TA, Error = EA>,
-    <A as InboundUpgrade<C>>::Future: Unpin,
     B: InboundUpgrade<C, Output = TB, Error = EB>,
-    <B as InboundUpgrade<C>>::Future: Unpin,
 {
     type Output = EitherOutput<TA, TB>;
     type Error = EitherError<EA, EB>;
@@ -70,9 +68,7 @@ where
 impl<C, A, B, TA, TB, EA, EB> OutboundUpgrade<C> for EitherUpgrade<A, B>
 where
     A: OutboundUpgrade<C, Output = TA, Error = EA>,
-    <A as OutboundUpgrade<C>>::Future: Unpin,
     B: OutboundUpgrade<C, Output = TB, Error = EB>,
-    <B as OutboundUpgrade<C>>::Future: Unpin,
 {
     type Output = EitherOutput<TA, TB>;
     type Error = EitherError<EA, EB>;
diff --git a/core/src/upgrade/select.rs b/core/src/upgrade/select.rs
index a8ee6504de7..35d82042db6 100644
--- a/core/src/upgrade/select.rs
+++ b/core/src/upgrade/select.rs
@@ -76,9 +76,7 @@ where
 impl<C, A, B, TA, TB, EA, EB> OutboundUpgrade<C> for SelectUpgrade<A, B>
 where
     A: OutboundUpgrade<C, Output = TA, Error = EA>,
-    <A as OutboundUpgrade<C>>::Future: Unpin,
     B: OutboundUpgrade<C, Output = TB, Error = EB>,
-    <B as OutboundUpgrade<C>>::Future: Unpin,
 {
     type Output = EitherOutput<TA, TB>;
     type Error = EitherError<EA, EB>;