impl IntoResponseParts for () (#2471)

axum-core/CHANGELOG.md

@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
-- None.
+- **added:** Implement `IntoResponseParts` for `()` ([#2471])
+
+[#2471]: https://github.com/tokio-rs/axum/pull/2471
 
 # 0.4.2 (29. December, 2023)
 

axum-core/src/response/into_response_parts.rs

@@ -258,3 +258,11 @@ impl IntoResponseParts for Extensions {
         Ok(res)
     }
 }
+
+impl IntoResponseParts for () {
+    type Error = Infallible;
+
+    fn into_response_parts(self, res: ResponseParts) -> Result<ResponseParts, Self::Error> {
+        Ok(res)
+    }
+}

axum-macros/tests/debug_handler/fail/wrong_return_type.stderr

@@ -12,7 +12,7 @@ error[E0277]: the trait bound `bool: IntoResponse` is not satisfied
             axum::extract::rejection::FailedToBufferBody
             axum::extract::rejection::LengthLimitError
             axum::extract::rejection::UnknownBodyError
-            axum::extract::rejection::InvalidUtf8
+            bytes::bytes_mut::BytesMut
           and $N others
 note: required by a bound in `__axum_macros_check_handler_into_response::{closure#0}::check`
  --> tests/debug_handler/fail/wrong_return_type.rs:4:23