diff --git a/actix-http/examples/res-ext.rs b/actix-http/examples/res-ext.rs
index 6418a301b..31809e7b0 100644
--- a/actix-http/examples/res-ext.rs
+++ b/actix-http/examples/res-ext.rs
@@ -1,8 +1,6 @@
 use std::{convert::Infallible, io};
 
-use actix_http::{
-    body::EitherBody, HttpMessage as _, HttpService, Request, Response, StatusCode,
-};
+use actix_http::{body::EitherBody, HttpService, Request, Response, StatusCode};
 use actix_server::Server;
 
 #[actix_rt::main]
diff --git a/actix-http/src/http_message.rs b/actix-http/src/http_message.rs
index 3c91b2f40..068e23b96 100644
--- a/actix-http/src/http_message.rs
+++ b/actix-http/src/http_message.rs
@@ -25,10 +25,10 @@ pub trait HttpMessage: Sized {
     /// Message payload stream
     fn take_payload(&mut self) -> Payload<Self::Stream>;
 
-    /// Returns a reference to the request-local data container.
+    /// Returns a reference to the request-local data/extensions container.
     fn extensions(&self) -> Ref<'_, Extensions>;
 
-    /// Returns a mutable reference to the request-local data container.
+    /// Returns a mutable reference to the request-local data/extensions container.
     fn extensions_mut(&self) -> RefMut<'_, Extensions>;
 
     /// Get a header.
diff --git a/actix-http/src/responses/response.rs b/actix-http/src/responses/response.rs
index 7a0bae516..6efc3c5f1 100644
--- a/actix-http/src/responses/response.rs
+++ b/actix-http/src/responses/response.rs
@@ -128,6 +128,18 @@ impl<B> Response<B> {
         self.head.keep_alive()
     }
 
+    /// Returns a reference to the request-local data/extensions container.
+    #[inline]
+    pub fn extensions(&self) -> Ref<'_, Extensions> {
+        self.extensions.borrow()
+    }
+
+    /// Returns a mutable reference to the request-local data/extensions container.
+    #[inline]
+    pub fn extensions_mut(&mut self) -> RefMut<'_, Extensions> {
+        self.extensions.borrow_mut()
+    }
+
     /// Returns a reference to the body of this response.
     #[inline]
     pub fn body(&self) -> &B {
diff --git a/src/app_service.rs b/src/app_service.rs
index 717e53ff7..b7c016e81 100644
--- a/src/app_service.rs
+++ b/src/app_service.rs
@@ -18,7 +18,7 @@ use crate::{
         AppServiceFactory, BoxedHttpService, BoxedHttpServiceFactory, ServiceRequest,
         ServiceResponse,
     },
-    Error, HttpMessage, HttpResponse,
+    Error, HttpResponse,
 };
 
 type Guards = Vec<Box<dyn Guard>>;
diff --git a/src/guard.rs b/src/guard.rs
index f4200a382..c21dccec1 100644
--- a/src/guard.rs
+++ b/src/guard.rs
@@ -54,7 +54,7 @@ use std::{
 
 use actix_http::{header, uri::Uri, Extensions, Method as HttpMethod, RequestHead};
 
-use crate::{http::header::Header, service::ServiceRequest};
+use crate::{http::header::Header, service::ServiceRequest, HttpMessage as _};
 
 /// Provides access to request parts that are useful during routing.
 #[derive(Debug)]
@@ -71,14 +71,14 @@ impl<'a> GuardContext<'a> {
 
     /// Returns reference to the request-local data container.
     #[inline]
-    pub fn req_data(&self) -> Ref<'a, Extensions> {
-        self.req.req_data()
+    pub fn extensions(&self) -> Ref<'a, Extensions> {
+        self.req.extensions()
     }
 
     /// Returns mutable reference to the request-local data container.
     #[inline]
-    pub fn req_data_mut(&self) -> RefMut<'a, Extensions> {
-        self.req.req_data_mut()
+    pub fn extensions_mut(&self) -> RefMut<'a, Extensions> {
+        self.req.extensions_mut()
     }
 
     /// Extracts a typed header from the request.
diff --git a/src/request_data.rs b/src/request_data.rs
index b685fd0d6..7f96bafec 100644
--- a/src/request_data.rs
+++ b/src/request_data.rs
@@ -2,7 +2,10 @@ use std::{any::type_name, ops::Deref};
 
 use actix_utils::future::{err, ok, Ready};
 
-use crate::{dev::Payload, error::ErrorInternalServerError, Error, FromRequest, HttpRequest};
+use crate::{
+    dev::Payload, error::ErrorInternalServerError, Error, FromRequest, HttpMessage as _,
+    HttpRequest,
+};
 
 /// Request-local data extractor.
 ///
@@ -23,7 +26,7 @@ use crate::{dev::Payload, error::ErrorInternalServerError, Error, FromRequest, H
 ///
 /// # Example
 /// ```no_run
-/// # use actix_web::{web, HttpResponse, HttpRequest, Responder};
+/// # use actix_web::{web, HttpResponse, HttpRequest, Responder, HttpMessage as _};
 ///
 /// #[derive(Debug, Clone, PartialEq)]
 /// struct FlagFromMiddleware(String);
@@ -35,7 +38,7 @@ use crate::{dev::Payload, error::ErrorInternalServerError, Error, FromRequest, H
 /// ) -> impl Responder {
 ///     // use an option extractor if middleware is not guaranteed to add this type of req data
 ///     if let Some(flag) = opt_flag {
-///         assert_eq!(&flag.into_inner(), req.req_data().get::<FlagFromMiddleware>().unwrap());
+///         assert_eq!(&flag.into_inner(), req.extensions().get::<FlagFromMiddleware>().unwrap());
 ///     }
 ///
 ///     HttpResponse::Ok()
@@ -67,7 +70,7 @@ impl<T: Clone + 'static> FromRequest for ReqData<T> {
     type Future = Ready<Result<Self, Error>>;
 
     fn from_request(req: &HttpRequest, _: &mut Payload) -> Self::Future {
-        if let Some(st) = req.req_data().get::<T>() {
+        if let Some(st) = req.extensions().get::<T>() {
             ok(ReqData(st.clone()))
         } else {
             log::debug!(
diff --git a/src/response/response.rs b/src/response/response.rs
index 74ccbad89..fc383fbc6 100644
--- a/src/response/response.rs
+++ b/src/response/response.rs
@@ -22,7 +22,7 @@ use {
     cookie::Cookie,
 };
 
-use crate::{error::Error, HttpMessage, HttpRequest, HttpResponseBuilder, Responder};
+use crate::{error::Error, HttpRequest, HttpResponseBuilder, Responder};
 
 /// An outgoing response.
 pub struct HttpResponse<B = BoxBody> {
@@ -180,22 +180,25 @@ impl<B> HttpResponse<B> {
         self.res.extensions_mut()
     }
 
-    /// Get body of this response
+    /// Returns a reference to this response's body.
     #[inline]
     pub fn body(&self) -> &B {
         self.res.body()
     }
 
-    /// Set a body
+    /// Sets new body.
     pub fn set_body<B2>(self, body: B2) -> HttpResponse<B2> {
         HttpResponse {
             res: self.res.set_body(body),
-            error: None,
-            // error: self.error, ??
+            error: self.error,
         }
     }
 
-    /// Split response and body
+    /// Returns split head and body.
+    ///
+    /// # Implementation Notes
+    /// Due to internal performance optimizations, the first element of the returned tuple is an
+    /// `HttpResponse` as well but only contains the head of the response this was called on.
     pub fn into_parts(self) -> (HttpResponse<()>, B) {
         let (head, body) = self.res.into_parts();
 
@@ -208,7 +211,7 @@ impl<B> HttpResponse<B> {
         )
     }
 
-    /// Drop request's body
+    /// Drops body and returns new response.
     pub fn drop_body(self) -> HttpResponse<()> {
         HttpResponse {
             res: self.res.drop_body(),
diff --git a/src/service.rs b/src/service.rs
index b8d6125a9..a8a86b51a 100644
--- a/src/service.rs
+++ b/src/service.rs
@@ -257,18 +257,6 @@ impl ServiceRequest {
         self.req.conn_data()
     }
 
-    /// Counterpart to [`HttpRequest::req_data`].
-    #[inline]
-    pub fn req_data(&self) -> Ref<'_, Extensions> {
-        self.req.req_data()
-    }
-
-    /// Counterpart to [`HttpRequest::req_data_mut`].
-    #[inline]
-    pub fn req_data_mut(&self) -> RefMut<'_, Extensions> {
-        self.req.req_data_mut()
-    }
-
     #[cfg(feature = "cookies")]
     #[inline]
     pub fn cookies(&self) -> Result<Ref<'_, Vec<Cookie<'static>>>, CookieParseError> {