diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 7683bf8438..0d7ff37cfc 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -82,6 +82,7 @@ jobs:
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
+          components: clippy
           toolchain: ${{ matrix.rust }}
           override: true
 
@@ -91,6 +92,12 @@ jobs:
           command: test
           args: ${{ matrix.features }}
 
+      - name: Clippy
+        uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: ${{ matrix.features }} --lib --examples --benches
+
       - name: Test all benches
         if: matrix.benches
         uses: actions-rs/cargo@v1
diff --git a/benches/body.rs b/benches/body.rs
index ea1a499bbf..86d8adbadf 100644
--- a/benches/body.rs
+++ b/benches/body.rs
@@ -1,3 +1,4 @@
+#![cfg(feature = "nightly")]
 #![feature(test)]
 #![deny(warnings)]
 
diff --git a/benches/connect.rs b/benches/connect.rs
index 34769cf930..6898dea1a1 100644
--- a/benches/connect.rs
+++ b/benches/connect.rs
@@ -1,8 +1,7 @@
+#![cfg(feature = "nightly")]
 #![feature(test)]
 #![deny(warnings)]
 
-extern crate test;
-
 // TODO: Reimplement http_connector bench using hyper::client::conn
 // (instead of removed HttpConnector).
 
diff --git a/benches/end_to_end.rs b/benches/end_to_end.rs
index 41dbde2ab0..076152e8c6 100644
--- a/benches/end_to_end.rs
+++ b/benches/end_to_end.rs
@@ -1,8 +1,7 @@
+#![cfg(feature = "nightly")]
 #![feature(test)]
 #![deny(warnings)]
 
-extern crate test;
-
 // TODO: Reimplement Opts::bench using hyper::server::conn and hyper::client::conn
 // (instead of Server and HttpClient).
 
diff --git a/benches/pipeline.rs b/benches/pipeline.rs
index a60100fa51..219ab755a3 100644
--- a/benches/pipeline.rs
+++ b/benches/pipeline.rs
@@ -1,3 +1,4 @@
+#![cfg(feature = "nightly")]
 #![feature(test)]
 #![deny(warnings)]
 
diff --git a/benches/server.rs b/benches/server.rs
index 17eefa0694..2b8e63e3c9 100644
--- a/benches/server.rs
+++ b/benches/server.rs
@@ -1,3 +1,4 @@
+#![cfg(feature = "nightly")]
 #![feature(test)]
 #![deny(warnings)]
 
@@ -149,7 +150,7 @@ fn raw_tcp_throughput_small_payload(b: &mut test::Bencher) {
 
         let mut buf = [0u8; 8192];
         while rx.try_recv().is_err() {
-            sock.read(&mut buf).unwrap();
+            let _ = sock.read(&mut buf).unwrap();
             sock.write_all(
                 b"\
                 HTTP/1.1 200 OK\r\n\
@@ -196,7 +197,7 @@ fn raw_tcp_throughput_large_payload(b: &mut test::Bencher) {
         let mut buf = [0u8; 8192];
         while rx.try_recv().is_err() {
             let r = sock.read(&mut buf).unwrap();
-            extern crate test;
+
             if r == 0 {
                 break;
             }
diff --git a/benches/support/tokiort.rs b/benches/support/tokiort.rs
index 49558f0a2c..ac841d1d11 100644
--- a/benches/support/tokiort.rs
+++ b/benches/support/tokiort.rs
@@ -32,13 +32,13 @@ impl Timer for TokioTimer {
     fn sleep(&self, duration: Duration) -> Box<dyn Sleep + Unpin> {
         let s = tokio::time::sleep(duration);
         let hs = TokioSleep { inner: Box::pin(s) };
-        return Box::new(hs);
+        Box::new(hs)
     }
 
     fn sleep_until(&self, deadline: Instant) -> Box<dyn Sleep + Unpin> {
-        return Box::new(TokioSleep {
+        Box::new(TokioSleep {
             inner: Box::pin(tokio::time::sleep_until(deadline.into())),
-        });
+        })
     }
 }
 
diff --git a/examples/client.rs b/examples/client.rs
index ffcc026719..dd5a004103 100644
--- a/examples/client.rs
+++ b/examples/client.rs
@@ -65,7 +65,7 @@ async fn fetch_url(url: hyper::Uri) -> Result<()> {
     while let Some(next) = res.frame().await {
         let frame = next?;
         if let Some(chunk) = frame.data_ref() {
-            io::stdout().write_all(&chunk).await?;
+            io::stdout().write_all(chunk).await?;
         }
     }
 
diff --git a/examples/gateway.rs b/examples/gateway.rs
index 2c8b8e17d5..0484d09317 100644
--- a/examples/gateway.rs
+++ b/examples/gateway.rs
@@ -11,8 +11,6 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let in_addr: SocketAddr = ([127, 0, 0, 1], 3001).into();
     let out_addr: SocketAddr = ([127, 0, 0, 1], 3000).into();
 
-    let out_addr_clone = out_addr.clone();
-
     let listener = TcpListener::bind(in_addr).await?;
 
     println!("Listening on http://{}", in_addr);
@@ -27,7 +25,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         let service = service_fn(move |mut req| {
             let uri_string = format!(
                 "http://{}{}",
-                out_addr_clone,
+                out_addr,
                 req.uri()
                     .path_and_query()
                     .map(|x| x.as_str())
diff --git a/examples/http_proxy.rs b/examples/http_proxy.rs
index 792e1e470d..a5baebfc61 100644
--- a/examples/http_proxy.rs
+++ b/examples/http_proxy.rs
@@ -104,7 +104,7 @@ async fn proxy(req: Request<Recv>) -> Result<Response<BoxBody<Bytes, hyper::Erro
 }
 
 fn host_addr(uri: &http::Uri) -> Option<String> {
-    uri.authority().and_then(|auth| Some(auth.to_string()))
+    uri.authority().map(|auth| auth.to_string())
 }
 
 fn empty() -> BoxBody<Bytes, hyper::Error> {
diff --git a/examples/upgrades.rs b/examples/upgrades.rs
index e5494e7bbb..3be9f3fb17 100644
--- a/examples/upgrades.rs
+++ b/examples/upgrades.rs
@@ -160,7 +160,6 @@ async fn main() {
                             res = &mut conn => {
                                 if let Err(err) = res {
                                     println!("Error serving connection: {:?}", err);
-                                    return;
                                 }
                             }
                             // Continue polling the connection after enabling graceful shutdown.
@@ -178,7 +177,7 @@ async fn main() {
     });
 
     // Client requests a HTTP connection upgrade.
-    let request = client_upgrade_request(addr.clone());
+    let request = client_upgrade_request(addr);
     if let Err(e) = request.await {
         eprintln!("client error: {}", e);
     }
diff --git a/examples/web_api.rs b/examples/web_api.rs
index 47c30cd852..7d56d87e56 100644
--- a/examples/web_api.rs
+++ b/examples/web_api.rs
@@ -111,7 +111,7 @@ async fn main() -> Result<()> {
         let (stream, _) = listener.accept().await?;
 
         tokio::task::spawn(async move {
-            let service = service_fn(move |req| response_examples(req));
+            let service = service_fn(response_examples);
 
             if let Err(err) = http1::Builder::new()
                 .serve_connection(stream, service)
diff --git a/src/body/body.rs b/src/body/body.rs
index f93030f7c7..7822a86691 100644
--- a/src/body/body.rs
+++ b/src/body/body.rs
@@ -125,14 +125,12 @@ impl Recv {
         if !content_length.is_exact() && recv.is_end_stream() {
             content_length = DecodedLength::ZERO;
         }
-        let body = Recv::new(Kind::H2 {
+        Recv::new(Kind::H2 {
             data_done: false,
             ping,
             content_length,
             recv,
-        });
-
-        body
+        })
     }
 
     #[cfg(feature = "ffi")]
@@ -170,13 +168,9 @@ impl Body for Recv {
                 want_tx.send(WANT_READY);
 
                 if !data_rx.is_terminated() {
-                    match ready!(Pin::new(data_rx).poll_next(cx)?) {
-                        Some(chunk) => {
-                            len.sub_if(chunk.len() as u64);
-                            return Poll::Ready(Some(Ok(Frame::data(chunk))));
-                        }
-                        // fall through to trailers
-                        None => (),
+                    if let Some(chunk) = ready!(Pin::new(data_rx).poll_next(cx)?) {
+                        len.sub_if(chunk.len() as u64);
+                        return Poll::Ready(Some(Ok(Frame::data(chunk))));
                     }
                 }
 
@@ -339,6 +333,7 @@ impl Sender {
 
     /// Aborts the body in an abnormal fashion.
     #[allow(unused)]
+    #[allow(clippy::redundant_clone)]
     pub(crate) fn abort(self) {
         let _ = self
             .data_tx
diff --git a/src/client/conn/http1.rs b/src/client/conn/http1.rs
index ad100f8819..ce99018aa8 100644
--- a/src/client/conn/http1.rs
+++ b/src/client/conn/http1.rs
@@ -33,6 +33,7 @@ pub struct SendRequest<B> {
 /// This allows taking apart a `Connection` at a later time, in order to
 /// reclaim the IO object, and additional related pieces.
 #[derive(Debug)]
+#[non_exhaustive]
 pub struct Parts<T> {
     /// The original IO object used in the handshake.
     pub io: T,
@@ -45,7 +46,6 @@ pub struct Parts<T> {
     /// You will want to check for any existing bytes if you plan to continue
     /// communicating on the IO object.
     pub read_buf: Bytes,
-    _inner: (),
 }
 
 
@@ -76,7 +76,6 @@ where
         Parts {
             io,
             read_buf,
-            _inner: (),
         }
     }
 
@@ -546,3 +545,9 @@ impl Builder {
         }
     }
 }
+
+impl std::default::Default for Builder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
diff --git a/src/client/conn/http2.rs b/src/client/conn/http2.rs
index ee7325d385..63ee836efc 100644
--- a/src/client/conn/http2.rs
+++ b/src/client/conn/http2.rs
@@ -441,3 +441,9 @@ impl Builder {
         }
     }
 }
+
+impl std::default::Default for Builder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
diff --git a/src/common/buf.rs b/src/common/buf.rs
index 64e9333ead..342c0309ff 100644
--- a/src/common/buf.rs
+++ b/src/common/buf.rs
@@ -8,12 +8,14 @@ pub(crate) struct BufList<T> {
 }
 
 impl<T: Buf> BufList<T> {
+    #[cfg(feature = "http1")]
     pub(crate) fn new() -> BufList<T> {
         BufList {
             bufs: VecDeque::new(),
         }
     }
 
+    #[cfg(feature = "http1")]
     #[inline]
     pub(crate) fn push(&mut self, buf: T) {
         debug_assert!(buf.has_remaining());
diff --git a/src/error.rs b/src/error.rs
index bc4414ab78..3d58592b65 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -67,6 +67,7 @@ pub(super) enum Parse {
     Header(Header),
     TooLarge,
     Status,
+    #[cfg(feature = "http1")]
     #[cfg_attr(debug_assertions, allow(unused))]
     Internal,
 }
@@ -193,7 +194,7 @@ impl Error {
     pub(crate) fn find_source<E: StdError + 'static>(&self) -> Option<&E> {
         let mut cause = self.source();
         while let Some(err) = cause {
-            if let Some(ref typed) = err.downcast_ref() {
+            if let Some(typed) = err.downcast_ref() {
                 return Some(typed);
             }
             cause = err.source();
@@ -351,6 +352,7 @@ impl Error {
             }
             Kind::Parse(Parse::TooLarge) => "message head is too large",
             Kind::Parse(Parse::Status) => "invalid HTTP status-code parsed",
+            #[cfg(feature = "http1")]
             Kind::Parse(Parse::Internal) => {
                 "internal error inside Hyper and/or its dependencies, please report"
             }
diff --git a/src/ext.rs b/src/ext.rs
index 6c54821e9d..6c80e73144 100644
--- a/src/ext.rs
+++ b/src/ext.rs
@@ -104,7 +104,7 @@ impl HeaderCaseMap {
         &'a self,
         name: &HeaderName,
     ) -> impl Iterator<Item = impl AsRef<[u8]> + 'a> + 'a {
-        self.get_all_internal(name).into_iter()
+        self.get_all_internal(name)
     }
 
     /// Returns a view of all spellings associated with that header name,
diff --git a/src/ext/h1_reason_phrase.rs b/src/ext/h1_reason_phrase.rs
index 021b632b6d..faad76121d 100644
--- a/src/ext/h1_reason_phrase.rs
+++ b/src/ext/h1_reason_phrase.rs
@@ -52,6 +52,8 @@ impl ReasonPhrase {
 
     /// Converts a `Bytes` directly into a `ReasonPhrase` without validating.
     ///
+    /// # Safety
+    ///
     /// Use with care; invalid bytes in a reason phrase can cause serious security problems if
     /// emitted in a response.
     pub unsafe fn from_bytes_unchecked(reason: Bytes) -> Self {
@@ -107,9 +109,9 @@ impl TryFrom<Bytes> for ReasonPhrase {
     }
 }
 
-impl Into<Bytes> for ReasonPhrase {
-    fn into(self) -> Bytes {
-        self.0
+impl From<ReasonPhrase> for Bytes {
+    fn from(rp: ReasonPhrase) -> Self {
+        rp.0
     }
 }
 
@@ -144,12 +146,9 @@ const fn is_valid_byte(b: u8) -> bool {
     }
 
     // See https://httpwg.org/http-core/draft-ietf-httpbis-semantics-latest.html#fields.values
-    //
-    // The 0xFF comparison is technically redundant, but it matches the text of the spec more
-    // clearly and will be optimized away.
     #[allow(unused_comparisons)]
     const fn is_obs_text(b: u8) -> bool {
-        0x80 <= b && b <= 0xFF
+        0x80 <= b /* && b <= 0xFF */
     }
 
     // See https://httpwg.org/http-core/draft-ietf-httpbis-messaging-latest.html#rfc.section.4.p.7
@@ -174,26 +173,26 @@ mod tests {
 
     #[test]
     fn basic_valid() {
-        const PHRASE: &'static [u8] = b"OK";
+        const PHRASE: &[u8] = b"OK";
         assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE);
         assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE);
     }
 
     #[test]
     fn empty_valid() {
-        const PHRASE: &'static [u8] = b"";
+        const PHRASE: &[u8] = b"";
         assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE);
         assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE);
     }
 
     #[test]
     fn obs_text_valid() {
-        const PHRASE: &'static [u8] = b"hyp\xe9r";
+        const PHRASE: &[u8] = b"hyp\xe9r";
         assert_eq!(ReasonPhrase::from_static(PHRASE).as_bytes(), PHRASE);
         assert_eq!(ReasonPhrase::try_from(PHRASE).unwrap().as_bytes(), PHRASE);
     }
 
-    const NEWLINE_PHRASE: &'static [u8] = b"hyp\ner";
+    const NEWLINE_PHRASE: &[u8] = b"hyp\ner";
 
     #[test]
     #[should_panic]
@@ -206,7 +205,7 @@ mod tests {
         assert!(ReasonPhrase::try_from(NEWLINE_PHRASE).is_err());
     }
 
-    const CR_PHRASE: &'static [u8] = b"hyp\rer";
+    const CR_PHRASE: &[u8] = b"hyp\rer";
 
     #[test]
     #[should_panic]
diff --git a/src/headers.rs b/src/headers.rs
index 8407be185f..7692e32918 100644
--- a/src/headers.rs
+++ b/src/headers.rs
@@ -61,7 +61,7 @@ pub(super) fn content_length_parse_all_values(values: ValueIter<'_, HeaderValue>
         }
     }
 
-    return content_length
+    content_length
 }
 
 fn from_digits(bytes: &[u8]) -> Option<u64> {
@@ -93,10 +93,7 @@ fn from_digits(bytes: &[u8]) -> Option<u64> {
 
 #[cfg(all(feature = "http2", feature = "client"))]
 pub(super) fn method_has_defined_payload_semantics(method: &Method) -> bool {
-    match *method {
-        Method::GET | Method::HEAD | Method::DELETE | Method::CONNECT => false,
-        _ => true,
-    }
+    !matches!(*method, Method::GET | Method::HEAD | Method::DELETE | Method::CONNECT)
 }
 
 #[cfg(feature = "http2")]
diff --git a/src/lib.rs b/src/lib.rs
index 2bd4d759d3..d8c8f5a1a8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,6 @@
 #![deny(missing_docs)]
 #![deny(missing_debug_implementations)]
+#![allow(clippy::module_inception)]
 #![cfg_attr(test, deny(rust_2018_idioms))]
 #![cfg_attr(all(test, feature = "full"), deny(unreachable_pub))]
 #![cfg_attr(all(test, feature = "full"), deny(warnings))]
diff --git a/src/proto/h1/conn.rs b/src/proto/h1/conn.rs
index 3250b7f3dc..22dbcf5bf8 100644
--- a/src/proto/h1/conn.rs
+++ b/src/proto/h1/conn.rs
@@ -169,10 +169,7 @@ where
     }
 
     pub(crate) fn can_read_body(&self) -> bool {
-        match self.state.reading {
-            Reading::Body(..) | Reading::Continue(..) => true,
-            _ => false,
-        }
+        matches!(self.state.reading, Reading::Body(..) | Reading::Continue(..))
     }
 
     fn should_error_on_eof(&self) -> bool {
@@ -185,6 +182,7 @@ where
         read_buf.len() >= 24 && read_buf[..24] == *H2_PREFACE
     }
 
+    #[allow(clippy::type_complexity)] // The return type is complex due to task-semantics
     pub(super) fn poll_read_head(
         &mut self,
         cx: &mut task::Context<'_>,
@@ -943,11 +941,7 @@ impl State {
     }
 
     fn wants_keep_alive(&self) -> bool {
-        if let KA::Disabled = self.keep_alive.status() {
-            false
-        } else {
-            true
-        }
+        !matches!(self.keep_alive.status(), KA::Disabled)
     }
 
     fn try_keep_alive<T: Http1Transaction>(&mut self) {
diff --git a/src/proto/h1/decode.rs b/src/proto/h1/decode.rs
index 4077b22062..73c79fc522 100644
--- a/src/proto/h1/decode.rs
+++ b/src/proto/h1/decode.rs
@@ -451,7 +451,7 @@ mod tests {
             let mut v = vec![0; len];
             let mut buf = ReadBuf::new(&mut v);
             ready!(Pin::new(self).poll_read(cx, &mut buf)?);
-            Poll::Ready(Ok(Bytes::copy_from_slice(&buf.filled())))
+            Poll::Ready(Ok(Bytes::copy_from_slice(buf.filled())))
         }
     }
 
@@ -487,8 +487,7 @@ mod tests {
                 let result =
                     futures_util::future::poll_fn(|cx| state.step(cx, rdr, &mut size, &mut None))
                         .await;
-                let desc = format!("read_size failed for {:?}", s);
-                state = result.expect(desc.as_str());
+                state = result.unwrap_or_else(|_| panic!("read_size failed for {:?}", s));
                 if state == ChunkedState::Body || state == ChunkedState::EndCr {
                     break;
                 }
diff --git a/src/proto/h1/dispatch.rs b/src/proto/h1/dispatch.rs
index a1c9341953..965176e021 100644
--- a/src/proto/h1/dispatch.rs
+++ b/src/proto/h1/dispatch.rs
@@ -19,6 +19,8 @@ pub(crate) struct Dispatcher<D, Bs: Body, I, T> {
     is_closing: bool,
 }
 
+pub(crate) type DispatchResult<Item, Body, Error> = Poll<Option<Result<(Item, Body), Error>>>;
+
 pub(crate) trait Dispatch {
     type PollItem;
     type PollBody;
@@ -27,7 +29,7 @@ pub(crate) trait Dispatch {
     fn poll_msg(
         self: Pin<&mut Self>,
         cx: &mut task::Context<'_>,
-    ) -> Poll<Option<Result<(Self::PollItem, Self::PollBody), Self::PollError>>>;
+    ) -> DispatchResult<Self::PollItem, Self::PollBody, Self::PollError>;
     fn recv_msg(&mut self, msg: crate::Result<(Self::RecvItem, Recv)>) -> crate::Result<()>;
     fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), ()>>;
     fn should_poll(&self) -> bool;
@@ -307,7 +309,7 @@ where
                             .size_hint()
                             .exact()
                             .map(BodyLength::Known)
-                            .or_else(|| Some(BodyLength::Unknown));
+                            .or(Some(BodyLength::Unknown));
                         self.body_rx.set(Some(body));
                         btype
                     };
diff --git a/src/proto/h1/io.rs b/src/proto/h1/io.rs
index da4101b6fb..5542fff9ee 100644
--- a/src/proto/h1/io.rs
+++ b/src/proto/h1/io.rs
@@ -344,7 +344,7 @@ where
     }
 
     #[cfg(test)]
-    fn flush<'a>(&'a mut self) -> impl std::future::Future<Output = io::Result<()>> + 'a {
+    fn flush(&mut self) -> impl std::future::Future<Output = io::Result<()>> + '_ {
         futures_util::future::poll_fn(move |cx| self.poll_flush(cx))
     }
 }
diff --git a/src/proto/h1/role.rs b/src/proto/h1/role.rs
index 37072384a2..80ab19004d 100644
--- a/src/proto/h1/role.rs
+++ b/src/proto/h1/role.rs
@@ -170,7 +170,7 @@ impl Http1Transaction for Server {
                         Version::HTTP_10
                     };
 
-                    record_header_indices(bytes, &req.headers, &mut headers_indices)?;
+                    record_header_indices(bytes, req.headers, &mut headers_indices)?;
                     headers_len = req.headers.len();
                 }
                 Ok(httparse::Status::Partial) => return Ok(None),
@@ -453,9 +453,10 @@ impl Http1Transaction for Server {
         };
 
         debug!("sending automatic response ({}) for parse error", status);
-        let mut msg = MessageHead::default();
-        msg.subject = status;
-        Some(msg)
+        Some(MessageHead {
+            subject: status,
+            ..MessageHead::default()
+        })
     }
 
     fn is_server() -> bool {
@@ -474,16 +475,13 @@ impl Server {
     }
 
     fn can_chunked(method: &Option<Method>, status: StatusCode) -> bool {
-        if method == &Some(Method::HEAD) || method == &Some(Method::CONNECT) && status.is_success()
+        if method == &Some(Method::HEAD)
+            || method == &Some(Method::CONNECT) && status.is_success()
+            || status.is_informational()
         {
             false
-        } else if status.is_informational() {
-            false
         } else {
-            match status {
-                StatusCode::NO_CONTENT | StatusCode::NOT_MODIFIED => false,
-                _ => true,
-            }
+            !matches!(status, StatusCode::NO_CONTENT | StatusCode::NOT_MODIFIED)
         }
     }
 
@@ -491,10 +489,7 @@ impl Server {
         if status.is_informational() || method == &Some(Method::CONNECT) && status.is_success() {
             false
         } else {
-            match status {
-                StatusCode::NO_CONTENT | StatusCode::NOT_MODIFIED => false,
-                _ => true,
-            }
+            !matches!(status, StatusCode::NO_CONTENT | StatusCode::NOT_MODIFIED)
         }
     }
 
@@ -970,7 +965,7 @@ impl Http1Transaction for Client {
                         } else {
                             Version::HTTP_10
                         };
-                        record_header_indices(bytes, &res.headers, &mut headers_indices)?;
+                        record_header_indices(bytes, res.headers, &mut headers_indices)?;
                         let headers_len = res.headers.len();
                         (len, status, reason, version, headers_len)
                     }
@@ -1646,7 +1641,7 @@ mod tests {
         Server::parse(&mut raw, ctx).unwrap_err();
     }
 
-    const H09_RESPONSE: &'static str = "Baguettes are super delicious, don't you agree?";
+    const H09_RESPONSE: &str = "Baguettes are super delicious, don't you agree?";
 
     #[test]
     fn test_parse_response_h09_allowed() {
@@ -1697,7 +1692,7 @@ mod tests {
         assert_eq!(raw, H09_RESPONSE);
     }
 
-    const RESPONSE_WITH_WHITESPACE_BETWEEN_HEADER_NAME_AND_COLON: &'static str =
+    const RESPONSE_WITH_WHITESPACE_BETWEEN_HEADER_NAME_AND_COLON: &str =
         "HTTP/1.1 200 OK\r\nAccess-Control-Allow-Credentials : true\r\n\r\n";
 
     #[test]
diff --git a/src/proto/h2/client.rs b/src/proto/h2/client.rs
index 92ab69cd56..fe3a9158bd 100644
--- a/src/proto/h2/client.rs
+++ b/src/proto/h2/client.rs
@@ -125,7 +125,7 @@ where
         }
     });
 
-    let ping_config = new_ping_config(&config);
+    let ping_config = new_ping_config(config);
 
     let (conn, ping) = if ping_config.is_enabled() {
         let pp = conn.ping_pong().expect("conn.ping_pong");
@@ -248,17 +248,16 @@ where
                     let eos = body.is_end_stream();
                     let ping = self.ping.clone();
 
-                    if is_connect {
-                        if headers::content_length_parse_all(req.headers())
+                    if is_connect
+                        && headers::content_length_parse_all(req.headers())
                             .map_or(false, |len| len != 0)
-                        {
-                            warn!("h2 connect request with non-zero body not supported");
-                            cb.send(Err((
-                                crate::Error::new_h2(h2::Reason::INTERNAL_ERROR.into()),
-                                None,
-                            )));
-                            continue;
-                        }
+                    {
+                        warn!("h2 connect request with non-zero body not supported");
+                        cb.send(Err((
+                            crate::Error::new_h2(h2::Reason::INTERNAL_ERROR.into()),
+                            None,
+                        )));
+                        continue;
                     }
 
                     if let Some(protocol) = req.extensions_mut().remove::<Protocol>() {
diff --git a/src/server/conn/http1.rs b/src/server/conn/http1.rs
index 421ef9cd72..2fe9449255 100644
--- a/src/server/conn/http1.rs
+++ b/src/server/conn/http1.rs
@@ -51,6 +51,7 @@ pub struct Builder {
 /// This allows taking apart a `Connection` at a later time, in order to
 /// reclaim the IO object, and additional related pieces.
 #[derive(Debug)]
+#[non_exhaustive]
 pub struct Parts<T, S> {
     /// The original IO object used in the handshake.
     pub io: T,
@@ -65,7 +66,6 @@ pub struct Parts<T, S> {
     pub read_buf: Bytes,
     /// The `Service` used to serve this connection.
     pub service: S,
-    _inner: (),
 }
 
 // ===== impl Connection =====
@@ -116,7 +116,6 @@ where
             io,
             read_buf,
             service: dispatch.into_service(),
-            _inner: (),
         }
     }
 
@@ -192,7 +191,7 @@ where
                         pending.manual();
                     }
                 };
-                return Poll::Ready(Ok(()));
+                Poll::Ready(Ok(()))
             }
             Err(e) =>  Poll::Ready(Err(e)),
         }
@@ -401,6 +400,12 @@ impl Builder {
     }
 }
 
+impl std::default::Default for Builder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 mod upgrades {
     use crate::upgrade::Upgraded;
 
diff --git a/src/server/conn/http2.rs b/src/server/conn/http2.rs
index e39aaf80e9..b4d52abcaa 100644
--- a/src/server/conn/http2.rs
+++ b/src/server/conn/http2.rs
@@ -104,7 +104,7 @@ impl<E> Builder<E> {
     /// This starts with the default options, and an executor.
     pub fn new(exec: E) -> Self {
         Self {
-            exec: exec,
+            exec,
             timer: Time::Empty,
             h2_builder: Default::default(),
         }
diff --git a/src/upgrade.rs b/src/upgrade.rs
index 1c7b5b01cd..117ef512bc 100644
--- a/src/upgrade.rs
+++ b/src/upgrade.rs
@@ -78,6 +78,7 @@ pub struct OnUpgrade {
 /// Includes the original IO type, and a read buffer of bytes that the
 /// HTTP state machine may have already read before completing an upgrade.
 #[derive(Debug)]
+#[non_exhaustive]
 pub struct Parts<T> {
     /// The original IO object used before the upgrade.
     pub io: T,
@@ -90,7 +91,6 @@ pub struct Parts<T> {
     /// You will want to check for any existing bytes if you plan to continue
     /// communicating on the IO object.
     pub read_buf: Bytes,
-    _inner: (),
 }
 
 /// Gets a pending HTTP upgrade from this message.
@@ -139,7 +139,6 @@ impl Upgraded {
             Ok(t) => Ok(Parts {
                 io: *t,
                 read_buf: buf,
-                _inner: (),
             }),
             Err(io) => Err(Upgraded {
                 io: Rewind::new_buffered(io, buf),
diff --git a/tests/client.rs b/tests/client.rs
index 508995046b..a6838f02b2 100644
--- a/tests/client.rs
+++ b/tests/client.rs
@@ -997,7 +997,7 @@ test! {
             \r\n\
             ",
         reply: {
-            let long_header = std::iter::repeat("A").take(500_000).collect::<String>();
+            let long_header = "A".repeat(500_000);
             format!("\
                 HTTP/1.1 200 OK\r\n\
                 {}: {}\r\n\
diff --git a/tests/server.rs b/tests/server.rs
index 6b798ef3e4..56fa27d9c3 100644
--- a/tests/server.rs
+++ b/tests/server.rs
@@ -1607,7 +1607,7 @@ async fn upgrades_new() {
 
         let response = s(&buf);
         assert!(response.starts_with("HTTP/1.1 101 Switching Protocols\r\n"));
-        assert!(!has_header(&response, "content-length"));
+        assert!(!has_header(response, "content-length"));
         let _ = read_101_tx.send(());
 
         let n = tcp.read(&mut buf).expect("read 2");
diff --git a/tests/support/mod.rs b/tests/support/mod.rs
index dced9a2e3b..8e0a875d7e 100644
--- a/tests/support/mod.rs
+++ b/tests/support/mod.rs
@@ -367,7 +367,7 @@ async fn async_test(cfg: __TestConfig) {
                 assert_eq!(req.method(), &sreq.method, "client method");
                 assert_eq!(req.version(), version, "client version");
                 for func in &sreq.headers {
-                    func(&req.headers());
+                    func(req.headers());
                 }
                 let sbody = sreq.body;
                 req.collect().map_ok(move |collected| {
@@ -456,7 +456,7 @@ async fn async_test(cfg: __TestConfig) {
             assert_eq!(res.status(), cstatus, "server status");
             assert_eq!(res.version(), version, "server version");
             for func in &cheaders {
-                func(&res.headers());
+                func(res.headers());
             }
 
             let body = res.collect().await.unwrap().to_bytes();