Remove the associated Body type on IntoResponse (#571)

axum-extra/src/extract/cached.rs

@@ -1,6 +1,6 @@
 use axum::{
     async_trait,
-    body::{boxed, BoxBody},
+    body::BoxBody,
     extract::{
         rejection::{ExtensionRejection, ExtensionsAlreadyExtracted},
         Extension, FromRequest, RequestParts,
@@ -30,7 +30,7 @@ use std::{
 /// use axum::{
 ///     async_trait,
 ///     extract::{FromRequest, RequestParts},
-///     body::{self, BoxBody},
+///     body::BoxBody,
 ///     response::IntoResponse,
 ///     http::{StatusCode, Response},
 /// };
@@ -67,7 +67,7 @@ use std::{
 ///         // once, in case other extractors for the same request also loads the session
 ///         let session: Session = Cached::<Session>::from_request(req)
 ///             .await
-///             .map_err(|err| err.into_response().map(body::boxed))?
+///             .map_err(|err| err.into_response())?
 ///             .0;
 ///
 ///         // load user from session...
@@ -157,13 +157,10 @@ impl<R> IntoResponse for CachedRejection<R>
 where
     R: IntoResponse,
 {
-    type Body = BoxBody;
-    type BodyError = <Self::Body as axum::body::HttpBody>::Error;
-
-    fn into_response(self) -> Response<Self::Body> {
+    fn into_response(self) -> Response<BoxBody> {
         match self {
-            Self::ExtensionsAlreadyExtracted(inner) => inner.into_response().map(boxed),
-            Self::Inner(inner) => inner.into_response().map(boxed),
+            Self::ExtensionsAlreadyExtracted(inner) => inner.into_response(),
+            Self::Inner(inner) => inner.into_response(),
         }
     }
 }

axum-extra/src/response/erased_json.rs

@@ -1,7 +1,5 @@
-use std::convert::Infallible;
-
 use axum::{
-    body::{Bytes, Full},
+    body::{self, BoxBody, Full},
     http::{header, HeaderValue, Response, StatusCode},
     response::IntoResponse,
 };
@@ -41,22 +39,19 @@ impl ErasedJson {
 }
 
 impl IntoResponse for ErasedJson {
-    type Body = Full<Bytes>;
-    type BodyError = Infallible;
-
-    fn into_response(self) -> Response<Self::Body> {
+    fn into_response(self) -> Response<BoxBody> {
         let bytes = match self.0 {
             Ok(res) => res,
             Err(err) => {
                 return Response::builder()
                     .status(StatusCode::INTERNAL_SERVER_ERROR)
                     .header(header::CONTENT_TYPE, mime::TEXT_PLAIN_UTF_8.as_ref())
-                    .body(Full::from(err.to_string()))
+                    .body(body::boxed(Full::from(err.to_string())))
                     .unwrap();
             }
         };
 
-        let mut res = Response::new(Full::from(bytes));
+        let mut res = Response::new(body::boxed(Full::from(bytes)));
         res.headers_mut().insert(
             header::CONTENT_TYPE,
             HeaderValue::from_static(mime::APPLICATION_JSON.as_ref()),