diff --git a/actix-cors/src/lib.rs b/actix-cors/src/lib.rs
index 40f9fdf99..db7e4cc4f 100644
--- a/actix-cors/src/lib.rs
+++ b/actix-cors/src/lib.rs
@@ -11,7 +11,7 @@
 //! use actix_cors::Cors;
 //! use actix_web::{http, web, App, HttpRequest, HttpResponse, HttpServer};
 //!
-//! fn index(req: HttpRequest) -> &'static str {
+//! async fn index(req: HttpRequest) -> &'static str {
 //!     "Hello world"
 //! }
 //!
diff --git a/actix-files/src/lib.rs b/actix-files/src/lib.rs
index 72db16957..2f8a5c49c 100644
--- a/actix-files/src/lib.rs
+++ b/actix-files/src/lib.rs
@@ -1176,9 +1176,11 @@ mod tests {
             let mut srv =
                 test::init_service(App::new().wrap(Compress::default()).service(
                     web::resource("/").to(|| {
-                        NamedFile::open("Cargo.toml")
-                            .unwrap()
-                            .set_content_encoding(header::ContentEncoding::Identity)
+                        async {
+                            NamedFile::open("Cargo.toml")
+                                .unwrap()
+                                .set_content_encoding(header::ContentEncoding::Identity)
+                        }
                     }),
                 ))
                 .await;
@@ -1199,9 +1201,11 @@ mod tests {
             let mut srv =
                 test::init_service(App::new().wrap(Compress::default()).service(
                     web::resource("/").to(|| {
-                        NamedFile::open("Cargo.toml")
-                            .unwrap()
-                            .set_content_encoding(header::ContentEncoding::Gzip)
+                        async {
+                            NamedFile::open("Cargo.toml")
+                                .unwrap()
+                                .set_content_encoding(header::ContentEncoding::Gzip)
+                        }
                     }),
                 ))
                 .await;
diff --git a/actix-http/src/message.rs b/actix-http/src/message.rs
index 316df2611..5994ed39e 100644
--- a/actix-http/src/message.rs
+++ b/actix-http/src/message.rs
@@ -388,6 +388,12 @@ impl BoxedResponseHead {
     pub fn new(status: StatusCode) -> Self {
         RESPONSE_POOL.with(|p| p.get_message(status))
     }
+
+    pub(crate) fn take(&mut self) -> Self {
+        BoxedResponseHead {
+            head: self.head.take(),
+        }
+    }
 }
 
 impl std::ops::Deref for BoxedResponseHead {
@@ -406,7 +412,9 @@ impl std::ops::DerefMut for BoxedResponseHead {
 
 impl Drop for BoxedResponseHead {
     fn drop(&mut self) {
-        RESPONSE_POOL.with(|p| p.release(self.head.take().unwrap()))
+        if let Some(head) = self.head.take() {
+            RESPONSE_POOL.with(move |p| p.release(head))
+        }
     }
 }
 
diff --git a/actix-http/src/response.rs b/actix-http/src/response.rs
index 31876813b..a5f18cc79 100644
--- a/actix-http/src/response.rs
+++ b/actix-http/src/response.rs
@@ -288,10 +288,7 @@ impl Future for Response {
 
     fn poll(mut self: Pin<&mut Self>, _: &mut Context) -> Poll<Self::Output> {
         Poll::Ready(Ok(Response {
-            head: std::mem::replace(
-                &mut self.head,
-                BoxedResponseHead::new(StatusCode::OK),
-            ),
+            head: self.head.take(),
             body: self.body.take_body(),
             error: self.error.take(),
         }))
diff --git a/actix-identity/src/lib.rs b/actix-identity/src/lib.rs
index 30761d872..2980a7753 100644
--- a/actix-identity/src/lib.rs
+++ b/actix-identity/src/lib.rs
@@ -16,7 +16,7 @@
 //! use actix_web::*;
 //! use actix_identity::{Identity, CookieIdentityPolicy, IdentityService};
 //!
-//! fn index(id: Identity) -> String {
+//! async fn index(id: Identity) -> String {
 //!     // access request identity
 //!     if let Some(id) = id.identity() {
 //!         format!("Welcome! {}", id)
@@ -25,12 +25,12 @@
 //!     }
 //! }
 //!
-//! fn login(id: Identity) -> HttpResponse {
+//! async fn login(id: Identity) -> HttpResponse {
 //!     id.remember("User1".to_owned()); // <- remember identity
 //!     HttpResponse::Ok().finish()
 //! }
 //!
-//! fn logout(id: Identity) -> HttpResponse {
+//! async fn logout(id: Identity) -> HttpResponse {
 //!     id.forget();                      // <- remove identity
 //!     HttpResponse::Ok().finish()
 //! }
@@ -764,11 +764,13 @@ mod tests {
                 .secure(false)
                 .name(COOKIE_NAME))))
                 .service(web::resource("/").to(|id: Identity| {
-                    let identity = id.identity();
-                    if identity.is_none() {
-                        id.remember(COOKIE_LOGIN.to_string())
+                    async move {
+                        let identity = id.identity();
+                        if identity.is_none() {
+                            id.remember(COOKIE_LOGIN.to_string())
+                        }
+                        web::Json(identity)
                     }
-                    web::Json(identity)
                 })),
         )
         .await
diff --git a/actix-session/src/cookie.rs b/actix-session/src/cookie.rs
index 9a486cce2..bb5fba97b 100644
--- a/actix-session/src/cookie.rs
+++ b/actix-session/src/cookie.rs
@@ -371,8 +371,10 @@ mod tests {
                 App::new()
                     .wrap(CookieSession::signed(&[0; 32]).secure(false))
                     .service(web::resource("/").to(|ses: Session| {
-                        let _ = ses.set("counter", 100);
-                        "test"
+                        async move {
+                            let _ = ses.set("counter", 100);
+                            "test"
+                        }
                     })),
             )
             .await;
@@ -394,8 +396,10 @@ mod tests {
                 App::new()
                     .wrap(CookieSession::private(&[0; 32]).secure(false))
                     .service(web::resource("/").to(|ses: Session| {
-                        let _ = ses.set("counter", 100);
-                        "test"
+                        async move {
+                            let _ = ses.set("counter", 100);
+                            "test"
+                        }
                     })),
             )
             .await;
@@ -417,8 +421,10 @@ mod tests {
                 App::new()
                     .wrap(CookieSession::signed(&[0; 32]).secure(false))
                     .service(web::resource("/").to(|ses: Session| {
-                        let _ = ses.set("counter", 100);
-                        "test"
+                        async move {
+                            let _ = ses.set("counter", 100);
+                            "test"
+                        }
                     })),
             )
             .await;
@@ -448,12 +454,16 @@ mod tests {
                             .max_age(100),
                     )
                     .service(web::resource("/").to(|ses: Session| {
-                        let _ = ses.set("counter", 100);
-                        "test"
+                        async move {
+                            let _ = ses.set("counter", 100);
+                            "test"
+                        }
                     }))
                     .service(web::resource("/test/").to(|ses: Session| {
-                        let val: usize = ses.get("counter").unwrap().unwrap();
-                        format!("counter: {}", val)
+                        async move {
+                            let val: usize = ses.get("counter").unwrap().unwrap();
+                            format!("counter: {}", val)
+                        }
                     })),
             )
             .await;
diff --git a/actix-web-codegen/tests/test_macro.rs b/actix-web-codegen/tests/test_macro.rs
index 953de9cd5..18c01f374 100644
--- a/actix-web-codegen/tests/test_macro.rs
+++ b/actix-web-codegen/tests/test_macro.rs
@@ -5,42 +5,42 @@ use actix_web_codegen::{connect, delete, get, head, options, patch, post, put, t
 use futures::{future, Future};
 
 #[get("/test")]
-fn test() -> impl Responder {
+async fn test() -> impl Responder {
     HttpResponse::Ok()
 }
 
 #[put("/test")]
-fn put_test() -> impl Responder {
+async fn put_test() -> impl Responder {
     HttpResponse::Created()
 }
 
 #[patch("/test")]
-fn patch_test() -> impl Responder {
+async fn patch_test() -> impl Responder {
     HttpResponse::Ok()
 }
 
 #[post("/test")]
-fn post_test() -> impl Responder {
+async fn post_test() -> impl Responder {
     HttpResponse::NoContent()
 }
 
 #[head("/test")]
-fn head_test() -> impl Responder {
+async fn head_test() -> impl Responder {
     HttpResponse::Ok()
 }
 
 #[connect("/test")]
-fn connect_test() -> impl Responder {
+async fn connect_test() -> impl Responder {
     HttpResponse::Ok()
 }
 
 #[options("/test")]
-fn options_test() -> impl Responder {
+async fn options_test() -> impl Responder {
     HttpResponse::Ok()
 }
 
 #[trace("/test")]
-fn trace_test() -> impl Responder {
+async fn trace_test() -> impl Responder {
     HttpResponse::Ok()
 }
 
@@ -55,17 +55,17 @@ fn auto_sync() -> impl Future<Output = Result<HttpResponse, actix_web::Error>> {
 }
 
 #[put("/test/{param}")]
-fn put_param_test(_: Path<String>) -> impl Responder {
+async fn put_param_test(_: Path<String>) -> impl Responder {
     HttpResponse::Created()
 }
 
 #[delete("/test/{param}")]
-fn delete_param_test(_: Path<String>) -> impl Responder {
+async fn delete_param_test(_: Path<String>) -> impl Responder {
     HttpResponse::NoContent()
 }
 
 #[get("/test/{param}")]
-fn get_param_test(_: Path<String>) -> impl Responder {
+async fn get_param_test(_: Path<String>) -> impl Responder {
     HttpResponse::Ok()
 }
 
diff --git a/awc/tests/test_client.rs b/awc/tests/test_client.rs
index 959380306..9e1948f79 100644
--- a/awc/tests/test_client.rs
+++ b/awc/tests/test_client.rs
@@ -115,14 +115,14 @@ fn test_form() {
 fn test_timeout() {
     block_on(async {
         let srv = TestServer::start(|| {
-            HttpService::new(App::new().service(web::resource("/").route(
-                web::to_async(|| {
+            HttpService::new(App::new().service(web::resource("/").route(web::to(
+                || {
                     async {
                         tokio_timer::delay_for(Duration::from_millis(200)).await;
                         Ok::<_, Error>(HttpResponse::Ok().body(STR))
                     }
-                }),
-            )))
+                },
+            ))))
         });
 
         let connector = awc::Connector::new()
@@ -149,14 +149,14 @@ fn test_timeout() {
 fn test_timeout_override() {
     block_on(async {
         let srv = TestServer::start(|| {
-            HttpService::new(App::new().service(web::resource("/").route(
-                web::to_async(|| {
+            HttpService::new(App::new().service(web::resource("/").route(web::to(
+                || {
                     async {
                         tokio_timer::delay_for(Duration::from_millis(200)).await;
                         Ok::<_, Error>(HttpResponse::Ok().body(STR))
                     }
-                }),
-            )))
+                },
+            ))))
         });
 
         let client = awc::Client::build()
@@ -693,12 +693,9 @@ fn test_client_brotli_encoding() {
 
 #[test]
 fn test_client_cookie_handling() {
+    use std::io::{Error as IoError, ErrorKind};
+
     block_on(async {
-        fn err() -> Error {
-            use std::io::{Error as IoError, ErrorKind};
-            // stub some generic error
-            Error::from(IoError::from(ErrorKind::NotFound))
-        }
         let cookie1 = Cookie::build("cookie1", "value1").finish();
         let cookie2 = Cookie::build("cookie2", "value2")
             .domain("www.example.org")
@@ -717,31 +714,45 @@ fn test_client_cookie_handling() {
             HttpService::new(App::new().route(
                 "/",
                 web::to(move |req: HttpRequest| {
-                    // Check cookies were sent correctly
-                    req.cookie("cookie1")
-                        .ok_or_else(err)
-                        .and_then(|c1| {
-                            if c1.value() == "value1" {
-                                Ok(())
-                            } else {
-                                Err(err())
-                            }
-                        })
-                        .and_then(|()| req.cookie("cookie2").ok_or_else(err))
-                        .and_then(|c2| {
-                            if c2.value() == "value2" {
-                                Ok(())
-                            } else {
-                                Err(err())
-                            }
-                        })
-                        // Send some cookies back
-                        .map(|_| {
-                            HttpResponse::Ok()
-                                .cookie(cookie1.clone())
-                                .cookie(cookie2.clone())
-                                .finish()
-                        })
+                    let cookie1 = cookie1.clone();
+                    let cookie2 = cookie2.clone();
+
+                    async move {
+                        // Check cookies were sent correctly
+                        let res: Result<(), Error> = req
+                            .cookie("cookie1")
+                            .ok_or(())
+                            .and_then(|c1| {
+                                if c1.value() == "value1" {
+                                    Ok(())
+                                } else {
+                                    Err(())
+                                }
+                            })
+                            .and_then(|()| req.cookie("cookie2").ok_or(()))
+                            .and_then(|c2| {
+                                if c2.value() == "value2" {
+                                    Ok(())
+                                } else {
+                                    Err(())
+                                }
+                            })
+                            .map_err(|_| {
+                                Error::from(IoError::from(ErrorKind::NotFound))
+                            });
+
+                        if let Err(e) = res {
+                            Err(e)
+                        } else {
+                            // Send some cookies back
+                            Ok::<_, Error>(
+                                HttpResponse::Ok()
+                                    .cookie(cookie1)
+                                    .cookie(cookie2)
+                                    .finish(),
+                            )
+                        }
+                    }
                 }),
             ))
         });
diff --git a/test-server/src/lib.rs b/test-server/src/lib.rs
index 1ec69b100..1911c75d6 100644
--- a/test-server/src/lib.rs
+++ b/test-server/src/lib.rs
@@ -35,7 +35,7 @@ pub use actix_testing::*;
 ///         let mut srv = TestServer::start(
 ///             || HttpService::new(
 ///                 App::new().service(
-///                     web::resource("/").to_async(my_handler))
+///                     web::resource("/").to(my_handler))
 ///             )
 ///         );
 ///