diff --git a/actix-http/src/body/response_body.rs b/actix-http/src/body/response_body.rs
index aa3c9b5ff..699ea9384 100644
--- a/actix-http/src/body/response_body.rs
+++ b/actix-http/src/body/response_body.rs
@@ -45,7 +45,8 @@ impl<B: MessageBody> ResponseBody<B> {
 
 impl<B> MessageBody for ResponseBody<B>
 where
-    B: MessageBody<Error = Error>,
+    B: MessageBody,
+    B::Error: Into<Error>,
 {
     type Error = Error;
 
@@ -66,7 +67,8 @@ where
 
 impl<B> Stream for ResponseBody<B>
 where
-    B: MessageBody<Error = Error>,
+    B: MessageBody,
+    B::Error: Into<Error>,
 {
     type Item = Result<Bytes, Error>;
 
@@ -75,7 +77,7 @@ where
         cx: &mut Context<'_>,
     ) -> Poll<Option<Self::Item>> {
         match self.project() {
-            ResponseBodyProj::Body(body) => body.poll_next(cx),
+            ResponseBodyProj::Body(body) => body.poll_next(cx).map_err(Into::into),
             ResponseBodyProj::Other(body) => Pin::new(body).poll_next(cx),
         }
     }
diff --git a/actix-http/src/h1/dispatcher.rs b/actix-http/src/h1/dispatcher.rs
index e98cf5e92..7ab89ba87 100644
--- a/actix-http/src/h1/dispatcher.rs
+++ b/actix-http/src/h1/dispatcher.rs
@@ -53,7 +53,7 @@ where
     S::Error: Into<Error>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -75,7 +75,7 @@ where
     S::Error: Into<Error>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -94,7 +94,7 @@ where
     S::Error: Into<Error>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -136,7 +136,7 @@ where
     X: Service<Request, Response = Request>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 {
     None,
     ExpectCall(#[pin] X::Future),
@@ -151,7 +151,7 @@ where
     X: Service<Request, Response = Request>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 {
     fn is_empty(&self) -> bool {
         matches!(self, State::None)
@@ -173,7 +173,7 @@ where
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -234,7 +234,7 @@ where
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -850,7 +850,7 @@ where
     S::Response: Into<Response<B>>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
diff --git a/actix-http/src/h2/dispatcher.rs b/actix-http/src/h2/dispatcher.rs
index b69035d36..fa26aa178 100644
--- a/actix-http/src/h2/dispatcher.rs
+++ b/actix-http/src/h2/dispatcher.rs
@@ -69,11 +69,14 @@ where
 impl<T, S, B, X, U> Future for Dispatcher<T, S, B, X, U>
 where
     T: AsyncRead + AsyncWrite + Unpin,
+
     S: Service<Request>,
     S::Error: Into<Error> + 'static,
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
-    B: MessageBody<Error = Error> + 'static,
+
+    B: MessageBody + 'static,
+    B::Error: Into<Error> + 'static,
 {
     type Output = Result<(), DispatchError>;
 
@@ -140,7 +143,9 @@ where
     F: Future<Output = Result<I, E>>,
     E: Into<Error>,
     I: Into<Response<B>>,
+
     B: MessageBody,
+    B::Error: Into<Error>,
 {
     fn prepare_response(
         &self,
@@ -216,7 +221,9 @@ where
     F: Future<Output = Result<I, E>>,
     E: Into<Error>,
     I: Into<Response<B>>,
-    B: MessageBody<Error = Error>,
+
+    B: MessageBody,
+    B::Error: Into<Error>,
 {
     type Output = ();
 
diff --git a/actix-http/src/service.rs b/actix-http/src/service.rs
index c5a54e46d..62af89adb 100644
--- a/actix-http/src/service.rs
+++ b/actix-http/src/service.rs
@@ -157,7 +157,7 @@ where
     <S::Service as Service<Request>>::Future: 'static,
 
     B: MessageBody + 'static,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: ServiceFactory<Request, Config = (), Response = Request>,
     X::Future: 'static,
@@ -209,7 +209,7 @@ mod openssl {
         <S::Service as Service<Request>>::Future: 'static,
 
         B: MessageBody + 'static,
-        B: MessageBody<Error = Error>,
+        B::Error: Into<Error>,
 
         X: ServiceFactory<Request, Config = (), Response = Request>,
         X::Future: 'static,
@@ -277,7 +277,7 @@ mod rustls {
         <S::Service as Service<Request>>::Future: 'static,
 
         B: MessageBody + 'static,
-        B: MessageBody<Error = Error>,
+        B::Error: Into<Error>,
 
         X: ServiceFactory<Request, Config = (), Response = Request>,
         X::Future: 'static,
@@ -342,7 +342,7 @@ where
     <S::Service as Service<Request>>::Future: 'static,
 
     B: MessageBody + 'static,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: ServiceFactory<Request, Config = (), Response = Request>,
     X::Future: 'static,
@@ -476,7 +476,7 @@ where
     S::Response: Into<Response<B>> + 'static,
 
     B: MessageBody + 'static,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -538,7 +538,7 @@ where
     S::Error: Into<Error>,
 
     B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -569,8 +569,8 @@ where
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
 
-    B: MessageBody + 'static,
-    B: MessageBody<Error = Error>,
+    B: MessageBody,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
@@ -591,8 +591,8 @@ where
     S::Future: 'static,
     S::Response: Into<Response<B>> + 'static,
 
-    B: MessageBody,
-    B: MessageBody<Error = Error>,
+    B: MessageBody + 'static,
+    B::Error: Into<Error>,
 
     X: Service<Request, Response = Request>,
     X::Error: Into<Error>,
diff --git a/actix-test/src/lib.rs b/actix-test/src/lib.rs
index e0aec7eea..5d85c2687 100644
--- a/actix-test/src/lib.rs
+++ b/actix-test/src/lib.rs
@@ -85,7 +85,8 @@ where
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
-    B: MessageBody<Error = Error> + 'static,
+    B: MessageBody + 'static,
+    B::Error: Into<Error>,
 {
     start_with(TestServerConfig::default(), factory)
 }
@@ -124,7 +125,8 @@ where
     S::InitError: fmt::Debug,
     S::Response: Into<Response<B>> + 'static,
     <S::Service as Service<Request>>::Future: 'static,
-    B: MessageBody<Error = Error> + 'static,
+    B: MessageBody + 'static,
+    B::Error: Into<Error>,
 {
     let (tx, rx) = mpsc::channel();