refactor(lib): resolve unused warning (#3344)

In CI, check unused_imports and dead_code

.github/workflows/CI.yml

@@ -146,6 +146,8 @@ jobs:
 
       - name: check --feature-powerset
         run: cargo hack --no-dev-deps check --feature-powerset --depth 2 --skip ffi,tracing
+        env:
+          RUSTFLAGS: "-D dead_code -D unused_imports"
 
   ffi:
     name: Test C API (FFI)

src/body/length.rs

@@ -33,7 +33,7 @@ impl DecodedLength {
     /// Should only be called if previously confirmed this isn't
     /// CLOSE_DELIMITED or CHUNKED.
     #[inline]
-    #[cfg(feature = "http1")]
+    #[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
     pub(crate) fn danger_len(self) -> u64 {
         debug_assert!(self.0 < Self::CHUNKED.0);
         self.0
@@ -72,7 +72,7 @@ impl DecodedLength {
     /// This includes 0, which of course is an exact known length.
     ///
     /// It would return false if "chunked" or otherwise size-unknown.
-    #[cfg(feature = "http2")]
+    #[cfg(all(any(feature = "client", feature = "server"), feature = "http2"))]
     pub(crate) fn is_exact(&self) -> bool {
         self.0 <= MAX_LEN
     }

src/body/mod.rs

@@ -26,7 +26,7 @@ pub use http_body::SizeHint;
 
 pub use self::incoming::Incoming;
 
-#[cfg(feature = "http1")]
+#[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
 pub(crate) use self::incoming::Sender;
 pub(crate) use self::length::DecodedLength;
 

src/client/dispatch.rs

@@ -1,17 +1,17 @@
 #[cfg(feature = "http2")]
 use std::future::Future;
 
+#[cfg(feature = "http2")]
 use http::{Request, Response};
+#[cfg(feature = "http2")]
 use http_body::Body;
+#[cfg(feature = "http2")]
 use pin_project_lite::pin_project;
 use tokio::sync::{mpsc, oneshot};
 
-use crate::{
-    body::Incoming,
-    common::{task, Poll},
-};
+use crate::common::{task, Poll};
 #[cfg(feature = "http2")]
-use crate::{common::Pin, proto::h2::client::ResponseFutMap};
+use crate::{body::Incoming, common::Pin, proto::h2::client::ResponseFutMap};
 
 #[cfg(test)]
 pub(crate) type RetryPromise<T, U> = oneshot::Receiver<Result<U, (crate::Error, Option<T>)>>;
@@ -21,6 +21,7 @@ pub(crate) fn channel<T, U>() -> (Sender<T, U>, Receiver<T, U>) {
     let (tx, rx) = mpsc::unbounded_channel();
     let (giver, taker) = want::new();
     let tx = Sender {
+        #[cfg(feature = "http1")]
         buffered_once: false,
         giver,
         inner: tx,
@@ -37,6 +38,7 @@ pub(crate) struct Sender<T, U> {
     /// One message is always allowed, even if the Receiver hasn't asked
     /// for it yet. This boolean keeps track of whether we've sent one
     /// without notice.
+    #[cfg(feature = "http1")]
     buffered_once: bool,
     /// The Giver helps watch that the the Receiver side has been polled
     /// when the queue is empty. This helps us know when a request and
@@ -59,20 +61,24 @@ pub(crate) struct UnboundedSender<T, U> {
 }
 
 impl<T, U> Sender<T, U> {
+    #[cfg(feature = "http1")]
     pub(crate) fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<crate::Result<()>> {
         self.giver
             .poll_want(cx)
             .map_err(|_| crate::Error::new_closed())
     }
 
+    #[cfg(feature = "http1")]
     pub(crate) fn is_ready(&self) -> bool {
         self.giver.is_wanting()
     }
 
+    #[cfg(feature = "http1")]
     pub(crate) fn is_closed(&self) -> bool {
         self.giver.is_canceled()
     }
 
+    #[cfg(feature = "http1")]
     fn can_send(&mut self) -> bool {
         if self.giver.give() || !self.buffered_once {
             // If the receiver is ready *now*, then of course we can send.
@@ -98,6 +104,7 @@ impl<T, U> Sender<T, U> {
             .map_err(|mut e| (e.0).0.take().expect("envelope not dropped").0)
     }
 
+    #[cfg(feature = "http1")]
     pub(crate) fn send(&mut self, val: T) -> Result<Promise<U>, T> {
         if !self.can_send() {
             return Err(val);

src/common/buf.rs

@@ -21,7 +21,6 @@ impl<T: Buf> BufList<T> {
     }
 
     #[inline]
-    #[cfg(feature = "http1")]
     pub(crate) fn bufs_cnt(&self) -> usize {
         self.bufs.len()
     }

src/common/io/mod.rs

@@ -1,7 +1,7 @@
-#[cfg(any(feature = "http2", test))]
+#[cfg(all(any(feature = "client", feature = "server"), feature = "http2"))]
 mod compat;
 mod rewind;
 
-#[cfg(any(feature = "http2", test))]
+#[cfg(all(any(feature = "client", feature = "server"), feature = "http2"))]
 pub(crate) use self::compat::{compat, Compat};
 pub(crate) use self::rewind::Rewind;

src/common/mod.rs

@@ -7,21 +7,22 @@ macro_rules! ready {
     };
 }
 
+#[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
 pub(crate) mod buf;
 #[cfg(all(feature = "server", any(feature = "http1", feature = "http2")))]
 pub(crate) mod date;
 #[cfg(not(feature = "http2"))]
 pub(crate) mod exec;
 pub(crate) mod io;
 pub(crate) mod task;
-#[cfg(any(feature = "http1", feature = "http2", feature = "server"))]
+#[cfg(any(
+    all(feature = "server", feature = "http1"),
+    all(any(feature = "client", feature = "server"), feature = "http2"),
+))]
 pub(crate) mod time;
 pub(crate) mod watch;
 
 pub(crate) use self::task::Poll;
 
 // group up types normally needed for `Future`
-cfg_proto! {
-    pub(crate) use std::marker::Unpin;
-}
 pub(crate) use std::{future::Future, pin::Pin};

src/common/task.rs

@@ -1,12 +1,10 @@
-#[cfg(feature = "http1")]
-use std::convert::Infallible;
 pub(crate) use std::task::{Context, Poll};
 
 /// A function to help "yield" a future, such that it is re-scheduled immediately.
 ///
 /// Useful for spin counts, so a future doesn't hog too much time.
-#[cfg(feature = "http1")]
-pub(crate) fn yield_now(cx: &mut Context<'_>) -> Poll<Infallible> {
+#[cfg(all(any(feature = "client", feature = "server"), feature = "http1"))]
+pub(crate) fn yield_now(cx: &mut Context<'_>) -> Poll<std::convert::Infallible> {
     cx.waker().wake_by_ref();
     Poll::Pending
 }

src/common/time.rs

@@ -1,8 +1,7 @@
+#[cfg(all(any(feature = "client", feature = "server"), feature = "http2"))]
+use std::time::Duration;
 use std::{fmt, sync::Arc};
-use std::{
-    pin::Pin,
-    time::{Duration, Instant},
-};
+use std::{pin::Pin, time::Instant};
 
 use crate::rt::Sleep;
 use crate::rt::Timer;
@@ -55,6 +54,7 @@ impl<F> Future for HyperTimeout<F> where F: Future {
 */
 
 impl Time {
+    #[cfg(all(any(feature = "client", feature = "server"), feature = "http2"))]
     pub(crate) fn sleep(&self, duration: Duration) -> Pin<Box<dyn Sleep>> {
         match *self {
             Time::Empty => {
@@ -64,6 +64,7 @@ impl Time {
         }
     }
 
+    #[cfg(feature = "http1")]
     pub(crate) fn sleep_until(&self, deadline: Instant) -> Pin<Box<dyn Sleep>> {
         match *self {
             Time::Empty => {