Work around rust-lang/rust#65863

src/error.rs

@@ -17,7 +17,7 @@ where
 
     /// Attempted to issue a `call` when no more requests can be in flight.
     ///
-    /// See [`tower_service::Service::poll_ready`] and [`Client::with_limit`].
+    /// See [`tower_service::Service::poll_ready`].
     TransportFull,
 
     /// Attempted to issue a `call`, but the underlying transport has been closed.

src/lib.rs

@@ -232,3 +232,20 @@ mod sealed {
 
 pub mod multiplex;
 pub mod pipeline;
+
+/// impl Future.
+///
+/// https://github.com/rust-lang/rust/issues/65863
+#[cfg(doc)]
+pub struct DocFuture<O>(std::marker::PhantomData<O>);
+
+#[cfg(doc)]
+impl<O> std::future::Future for DocFuture<O> {
+    type Output = O;
+    fn poll(
+        self: std::pin::Pin<&mut Self>,
+        _: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Self::Output> {
+        unreachable!()
+    }
+}

src/multiplex/client.rs

@@ -93,7 +93,11 @@ where
 {
     type Error = SpawnError<NT::MakeError>;
     type Response = Client<NT::Transport, Error<NT::Transport, Request>, Request>;
+
+    #[cfg(not(doc))]
     type Future = impl Future<Output = Result<Self::Response, Self::Error>> + Send;
+    #[cfg(doc)]
+    type Future = crate::DocFuture<Result<Self::Response, Self::Error>>;
 
     fn call(&mut self, target: Target) -> Self::Future {
         let maker = self.t_maker.make_transport(target);
@@ -390,7 +394,11 @@ where
 {
     type Response = T::Ok;
     type Error = E;
+
+    #[cfg(not(doc))]
     type Future = impl Future<Output = Result<Self::Response, Self::Error>> + Send;
+    #[cfg(doc)]
+    type Future = crate::DocFuture<Result<Self::Response, Self::Error>>;
 
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), E>> {
         Poll::Ready(ready!(self.mediator.poll_ready(cx)).map_err(|_| E::from(Error::ClientDropped)))

src/multiplex/mod.rs

@@ -26,7 +26,7 @@ pub mod server;
 pub use self::server::Server;
 
 /// A convenience wrapper that lets you take separate transport and tag store types and use them as
-/// a single [`client::Transport`].
+/// a single transport.
 #[pin_project]
 #[derive(Debug)]
 pub struct MultiplexTransport<T, S> {

src/pipeline/client.rs

@@ -72,7 +72,11 @@ where
 {
     type Error = SpawnError<NT::MakeError>;
     type Response = Client<NT::Transport, Error<NT::Transport, Request>, Request>;
+
+    #[cfg(not(doc))]
     type Future = impl Future<Output = Result<Self::Response, Self::Error>> + Send;
+    #[cfg(doc)]
+    type Future = crate::DocFuture<Result<Self::Response, Self::Error>>;
 
     fn call(&mut self, target: Target) -> Self::Future {
         let maker = self.t_maker.make_transport(target);
@@ -350,7 +354,11 @@ where
 {
     type Response = T::Ok;
     type Error = E;
+
+    #[cfg(not(doc))]
     type Future = impl Future<Output = Result<Self::Response, Self::Error>> + Send;
+    #[cfg(doc)]
+    type Future = crate::DocFuture<Result<Self::Response, Self::Error>>;
 
     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), E>> {
         Poll::Ready(ready!(self.mediator.poll_ready(cx)).map_err(|_| E::from(Error::ClientDropped)))