diff --git a/actix-connect/src/ssl/rustls.rs b/actix-connect/src/ssl/rustls.rs
index 01cb2fab..1964b3aa 100644
--- a/actix-connect/src/ssl/rustls.rs
+++ b/actix-connect/src/ssl/rustls.rs
@@ -38,7 +38,7 @@ where
 {
     pub fn service(connector: Arc<ClientConfig>) -> RustlsConnectorService<T, U> {
         RustlsConnectorService {
-            connector: connector,
+            connector,
             _t: PhantomData,
         }
     }
diff --git a/actix-ioframe/src/dispatcher.rs b/actix-ioframe/src/dispatcher.rs
index 1565f797..3e000da6 100644
--- a/actix-ioframe/src/dispatcher.rs
+++ b/actix-ioframe/src/dispatcher.rs
@@ -213,7 +213,7 @@ where
                 // drain service responses
                 match Pin::new(&mut self.rx).poll_next(cx) {
                     Poll::Ready(Some(Ok(msg))) => {
-                        if let Err(_) = self.framed.write(msg) {
+                        if self.framed.write(msg).is_err() {
                             return Poll::Ready(Ok(()));
                         }
                     }
diff --git a/actix-macros/src/lib.rs b/actix-macros/src/lib.rs
index ec270f28..b6a57b9d 100644
--- a/actix-macros/src/lib.rs
+++ b/actix-macros/src/lib.rs
@@ -14,6 +14,7 @@ use quote::quote;
 ///     println!("Hello world");
 /// }
 /// ```
+#[allow(clippy::needless_doctest_main)]
 #[proc_macro_attribute]
 #[cfg(not(test))] // Work around for rust-lang/rust#62127
 pub fn main(_: TokenStream, item: TokenStream) -> TokenStream {
diff --git a/actix-rt/src/runtime.rs b/actix-rt/src/runtime.rs
index a03361d6..bbafb6f0 100644
--- a/actix-rt/src/runtime.rs
+++ b/actix-rt/src/runtime.rs
@@ -86,7 +86,6 @@ impl Runtime {
     where
         F: Future + 'static,
     {
-        let res = self.local.block_on(&mut self.rt, f);
-        res
+        self.local.block_on(&mut self.rt, f)
     }
 }
diff --git a/actix-server/src/builder.rs b/actix-server/src/builder.rs
index 0f3722c9..ee1c3e2f 100644
--- a/actix-server/src/builder.rs
+++ b/actix-server/src/builder.rs
@@ -220,7 +220,7 @@ impl ServerBuilder {
         self.services.push(StreamNewService::create(
             name.as_ref().to_string(),
             token,
-            factory.clone(),
+            factory,
             addr,
         ));
         self.sockets
diff --git a/actix-server/src/config.rs b/actix-server/src/config.rs
index d1060ec5..464635b1 100644
--- a/actix-server/src/config.rs
+++ b/actix-server/src/config.rs
@@ -91,7 +91,7 @@ impl ConfiguredService {
 
     pub(super) fn stream(&mut self, token: Token, name: String, addr: net::SocketAddr) {
         self.names.insert(token, (name.clone(), addr));
-        self.topics.insert(name.clone(), token);
+        self.topics.insert(name, token);
         self.services.push(token);
     }
 }
diff --git a/actix-server/src/worker.rs b/actix-server/src/worker.rs
index 4dbe3493..f51fd310 100644
--- a/actix-server/src/worker.rs
+++ b/actix-server/src/worker.rs
@@ -315,6 +315,8 @@ enum WorkerState {
 impl Future for Worker {
     type Output = ();
 
+    // FIXME: remove this attribute
+    #[allow(clippy::never_loop)]
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         // `StopWorker` message handler
         if let Poll::Ready(Some(StopCommand { graceful, result })) =
@@ -368,11 +370,8 @@ impl Future for Worker {
                     Ok(false) => {
                         // push connection back to queue
                         if let Some(conn) = conn {
-                            match self.state {
-                                WorkerState::Unavailable(ref mut conns) => {
-                                    conns.push(conn);
-                                }
-                                _ => (),
+                            if let WorkerState::Unavailable(ref mut conns) = self.state {
+                                conns.push(conn);
                             }
                         }
                         Poll::Pending
diff --git a/actix-server/tests/test_server.rs b/actix-server/tests/test_server.rs
index a1cf1928..46587a80 100644
--- a/actix-server/tests/test_server.rs
+++ b/actix-server/tests/test_server.rs
@@ -41,7 +41,7 @@ fn test_bind() {
 
     thread::sleep(time::Duration::from_millis(500));
     assert!(net::TcpStream::connect(addr).is_ok());
-    let _ = sys.stop();
+    sys.stop();
     let _ = h.join();
 }
 
@@ -66,7 +66,7 @@ fn test_listen() {
 
     thread::sleep(time::Duration::from_millis(500));
     assert!(net::TcpStream::connect(addr).is_ok());
-    let _ = sys.stop();
+    sys.stop();
     let _ = h.join();
 }
 
@@ -130,7 +130,7 @@ fn test_start() {
     assert!(net::TcpStream::connect(addr).is_err());
 
     thread::sleep(time::Duration::from_millis(100));
-    let _ = sys.stop();
+    sys.stop();
     let _ = h.join();
 }
 
@@ -178,6 +178,6 @@ fn test_configure() {
     assert!(net::TcpStream::connect(addr2).is_ok());
     assert!(net::TcpStream::connect(addr3).is_ok());
     assert_eq!(num.load(Relaxed), 1);
-    let _ = sys.stop();
+    sys.stop();
     let _ = h.join();
 }
diff --git a/actix-service/src/and_then.rs b/actix-service/src/and_then.rs
index b67de0a0..76ed35e9 100644
--- a/actix-service/src/and_then.rs
+++ b/actix-service/src/and_then.rs
@@ -313,7 +313,7 @@ mod tests {
         let mut srv = pipeline(Srv1(cnt.clone())).and_then(Srv2(cnt));
         let res = srv.call("srv1").await;
         assert!(res.is_ok());
-        assert_eq!(res.unwrap(), (("srv1", "srv2")));
+        assert_eq!(res.unwrap(), ("srv1", "srv2"));
     }
 
     #[actix_rt::test]
diff --git a/actix-service/src/and_then_apply_fn.rs b/actix-service/src/and_then_apply_fn.rs
index 4ff3b4d0..07f3b50d 100644
--- a/actix-service/src/and_then_apply_fn.rs
+++ b/actix-service/src/and_then_apply_fn.rs
@@ -290,6 +290,7 @@ mod tests {
             Poll::Ready(Ok(()))
         }
 
+        #[allow(clippy::unit_arg)]
         fn call(&mut self, req: Self::Request) -> Self::Future {
             ok(req)
         }
@@ -297,7 +298,7 @@ mod tests {
 
     #[actix_rt::test]
     async fn test_service() {
-        let mut srv = pipeline(|r: &'static str| ok(r))
+        let mut srv = pipeline(ok)
             .and_then_apply_fn(Srv, |req: &'static str, s| {
                 s.call(()).map_ok(move |res| (req, res))
             });
@@ -311,7 +312,7 @@ mod tests {
 
     #[actix_rt::test]
     async fn test_service_factory() {
-        let new_srv = pipeline_factory(|| ok::<_, ()>(fn_service(|r: &'static str| ok(r))))
+        let new_srv = pipeline_factory(|| ok::<_, ()>(fn_service(ok)))
             .and_then_apply_fn(
                 || ok(Srv),
                 |req: &'static str, s| s.call(()).map_ok(move |res| (req, res)),
diff --git a/actix-service/src/apply.rs b/actix-service/src/apply.rs
index b8cc7426..df5df317 100644
--- a/actix-service/src/apply.rs
+++ b/actix-service/src/apply.rs
@@ -233,8 +233,8 @@ mod tests {
         let mut srv = pipeline(apply_fn(Srv, |req: &'static str, srv| {
             let fut = srv.call(());
             async move {
-                let res = fut.await.unwrap();
-                Ok((req, res))
+                fut.await.unwrap();
+                Ok((req, ()))
             }
         }));
 
@@ -242,7 +242,7 @@ mod tests {
 
         let res = srv.call("srv").await;
         assert!(res.is_ok());
-        assert_eq!(res.unwrap(), (("srv", ())));
+        assert_eq!(res.unwrap(), ("srv", ()));
     }
 
     #[actix_rt::test]
@@ -252,8 +252,8 @@ mod tests {
             |req: &'static str, srv| {
                 let fut = srv.call(());
                 async move {
-                    let res = fut.await.unwrap();
-                    Ok((req, res))
+                    fut.await.unwrap();
+                    Ok((req, ()))
                 }
             },
         ));
@@ -264,6 +264,6 @@ mod tests {
 
         let res = srv.call("srv").await;
         assert!(res.is_ok());
-        assert_eq!(res.unwrap(), (("srv", ())));
+        assert_eq!(res.unwrap(), ("srv", ()));
     }
 }
diff --git a/actix-service/src/then.rs b/actix-service/src/then.rs
index b3a624ab..53ff1753 100644
--- a/actix-service/src/then.rs
+++ b/actix-service/src/then.rs
@@ -305,11 +305,11 @@ mod tests {
 
         let res = srv.call(Ok("srv1")).await;
         assert!(res.is_ok());
-        assert_eq!(res.unwrap(), (("srv1", "ok")));
+        assert_eq!(res.unwrap(), ("srv1", "ok"));
 
         let res = srv.call(Err("srv")).await;
         assert!(res.is_ok());
-        assert_eq!(res.unwrap(), (("srv2", "err")));
+        assert_eq!(res.unwrap(), ("srv2", "err"));
     }
 
     #[actix_rt::test]
@@ -321,10 +321,10 @@ mod tests {
         let mut srv = factory.new_service(&()).await.unwrap();
         let res = srv.call(Ok("srv1")).await;
         assert!(res.is_ok());
-        assert_eq!(res.unwrap(), (("srv1", "ok")));
+        assert_eq!(res.unwrap(), ("srv1", "ok"));
 
         let res = srv.call(Err("srv")).await;
         assert!(res.is_ok());
-        assert_eq!(res.unwrap(), (("srv2", "err")));
+        assert_eq!(res.unwrap(), ("srv2", "err"));
     }
 }
diff --git a/actix-testing/src/lib.rs b/actix-testing/src/lib.rs
index 4fd68f9a..c1e192e1 100644
--- a/actix-testing/src/lib.rs
+++ b/actix-testing/src/lib.rs
@@ -1,6 +1,6 @@
 //! Various helpers for Actix applications to use during testing.
 #![deny(rust_2018_idioms, warnings)]
-#![allow(clippy::type_complexity)]
+#![allow(clippy::type_complexity, clippy::needless_doctest_main)]
 
 use std::sync::mpsc;
 use std::{net, thread};
diff --git a/actix-utils/src/condition.rs b/actix-utils/src/condition.rs
index 8830453d..097034da 100644
--- a/actix-utils/src/condition.rs
+++ b/actix-utils/src/condition.rs
@@ -107,7 +107,7 @@ mod tests {
             Poll::Pending
         );
         cond.notify();
-        assert_eq!(waiter.await, ());
+        waiter.await;
 
         let mut waiter = cond.wait();
         assert_eq!(
@@ -121,7 +121,7 @@ mod tests {
         );
 
         drop(cond);
-        assert_eq!(waiter.await, ());
-        assert_eq!(waiter2.await, ());
+        waiter.await;
+        waiter2.await;
     }
 }
diff --git a/actix-utils/src/order.rs b/actix-utils/src/order.rs
index fc099b6e..7dd4e2fc 100644
--- a/actix-utils/src/order.rs
+++ b/actix-utils/src/order.rs
@@ -242,7 +242,7 @@ mod tests {
             let rx2 = rx2;
             let rx3 = rx3;
             let tx_stop = tx_stop;
-            let _ = actix_rt::System::new("test").block_on(async {
+            actix_rt::System::new("test").block_on(async {
                 let mut srv = InOrderService::new(Srv);
 
                 let _ = lazy(|cx| srv.poll_ready(cx)).await;
@@ -251,7 +251,7 @@ mod tests {
                 let res3 = srv.call(rx3);
 
                 actix_rt::spawn(async move {
-                    let _ = poll_fn(|cx| {
+                    poll_fn(|cx| {
                         let _ = srv.poll_ready(cx);
                         Poll::<()>::Pending
                     })
diff --git a/router/src/lib.rs b/router/src/lib.rs
index 7e41c4c3..75485b5a 100644
--- a/router/src/lib.rs
+++ b/router/src/lib.rs
@@ -69,7 +69,7 @@ impl<'a> IntoPattern for &'a str {
     }
 
     fn patterns(&self) -> Vec<String> {
-        vec![self.to_string()]
+        vec![(*self).to_string()]
     }
 }
 
@@ -79,7 +79,7 @@ impl<T: AsRef<str>> IntoPattern for Vec<T> {
     }
 
     fn patterns(&self) -> Vec<String> {
-        self.into_iter().map(|v| v.as_ref().to_string()).collect()
+        self.iter().map(|v| v.as_ref().to_string()).collect()
     }
 }
 
diff --git a/router/src/resource.rs b/router/src/resource.rs
index 00157775..b8a8c4d4 100644
--- a/router/src/resource.rs
+++ b/router/src/resource.rs
@@ -294,7 +294,7 @@ impl ResourceDef {
                     return false;
                 }
                 for idx in 0..idx {
-                    path.add(names[idx].clone(), segments[idx]);
+                    path.add(names[idx], segments[idx]);
                 }
                 path.skip((pos + len) as u16);
                 true
@@ -326,7 +326,7 @@ impl ResourceDef {
                         return false;
                     }
                     for idx in 0..idx {
-                        path.add(names[idx].clone(), segments[idx]);
+                        path.add(names[idx], segments[idx]);
                     }
                     path.skip((pos + len) as u16);
                     true
@@ -413,7 +413,7 @@ impl ResourceDef {
 
                 let path = res.resource_path();
                 for idx in 0..idx {
-                    path.add(names[idx].clone(), segments[idx]);
+                    path.add(names[idx], segments[idx]);
                 }
                 path.skip((pos + len) as u16);
                 true
@@ -452,7 +452,7 @@ impl ResourceDef {
 
                     let path = res.resource_path();
                     for idx in 0..idx {
-                        path.add(names[idx].clone(), segments[idx]);
+                        path.add(names[idx], segments[idx]);
                     }
                     path.skip((pos + len) as u16);
                     true
@@ -734,6 +734,7 @@ mod tests {
         assert_eq!(path.get("id").unwrap(), "012345");
     }
 
+    #[allow(clippy::cognitive_complexity)]
     #[test]
     fn test_dynamic_set() {
         let re = ResourceDef::new(vec![
@@ -899,31 +900,31 @@ mod tests {
     fn test_resource_path() {
         let mut s = String::new();
         let resource = ResourceDef::new("/user/{item1}/test");
-        assert!(resource.resource_path(&mut s, &mut (&["user1"]).into_iter()));
+        assert!(resource.resource_path(&mut s, &mut (&["user1"]).iter()));
         assert_eq!(s, "/user/user1/test");
 
         let mut s = String::new();
         let resource = ResourceDef::new("/user/{item1}/{item2}/test");
-        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).into_iter()));
+        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).iter()));
         assert_eq!(s, "/user/item/item2/test");
 
         let mut s = String::new();
         let resource = ResourceDef::new("/user/{item1}/{item2}");
-        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).into_iter()));
+        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).iter()));
         assert_eq!(s, "/user/item/item2");
 
         let mut s = String::new();
         let resource = ResourceDef::new("/user/{item1}/{item2}/");
-        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).into_iter()));
+        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).iter()));
         assert_eq!(s, "/user/item/item2/");
 
         let mut s = String::new();
-        assert!(!resource.resource_path(&mut s, &mut (&["item"]).into_iter()));
+        assert!(!resource.resource_path(&mut s, &mut (&["item"]).iter()));
 
         let mut s = String::new();
-        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).into_iter()));
+        assert!(resource.resource_path(&mut s, &mut (&["item", "item2"]).iter()));
         assert_eq!(s, "/user/item/item2/");
-        assert!(!resource.resource_path(&mut s, &mut (&["item"]).into_iter()));
+        assert!(!resource.resource_path(&mut s, &mut (&["item"]).iter()));
 
         let mut s = String::new();
         assert!(resource.resource_path(&mut s, &mut vec!["item", "item2"].into_iter()));
diff --git a/router/src/router.rs b/router/src/router.rs
index c65ac2db..bcbe61f9 100644
--- a/router/src/router.rs
+++ b/router/src/router.rs
@@ -104,6 +104,7 @@ mod tests {
     use crate::path::Path;
     use crate::router::{ResourceId, Router};
 
+    #[allow(clippy::cognitive_complexity)]
     #[test]
     fn test_recognizer_1() {
         let mut router = Router::<usize>::build();
diff --git a/string/src/lib.rs b/string/src/lib.rs
index 6e5d422f..2b600bde 100644
--- a/string/src/lib.rs
+++ b/string/src/lib.rs
@@ -204,7 +204,7 @@ mod test {
 
     #[test]
     fn test_from_static_str() {
-        const _S: ByteString = ByteString::from_static("hello");
+        static _S: ByteString = ByteString::from_static("hello");
         let _ = ByteString::from_static("str");
     }