From b3e3f42e2467b079f2ce7660a64273bb9b887a03 Mon Sep 17 00:00:00 2001
From: David Pedersen <david.pdrsn@gmail.com>
Date: Thu, 3 Aug 2023 20:15:06 +0200
Subject: [PATCH] Implement `IntoResponse` for `(R,) where R: IntoResponse`
 (#2143)

---
 axum-core/src/response/into_response.rs                | 10 ++++++++++
 .../tests/debug_handler/fail/wrong_return_type.stderr  |  2 +-
 axum/CHANGELOG.md                                      |  4 +++-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/axum-core/src/response/into_response.rs b/axum-core/src/response/into_response.rs
index 898252a2e3..d1c67e5cf0 100644
--- a/axum-core/src/response/into_response.rs
+++ b/axum-core/src/response/into_response.rs
@@ -449,6 +449,16 @@ where
     }
 }
 
+impl<R> IntoResponse for (R,)
+where
+    R: IntoResponse,
+{
+    fn into_response(self) -> Response {
+        let (res,) = self;
+        res.into_response()
+    }
+}
+
 macro_rules! impl_into_response {
     ( $($ty:ident),* $(,)? ) => {
         #[allow(non_snake_case)]
diff --git a/axum-macros/tests/debug_handler/fail/wrong_return_type.stderr b/axum-macros/tests/debug_handler/fail/wrong_return_type.stderr
index 151c5f84bf..a76569102b 100644
--- a/axum-macros/tests/debug_handler/fail/wrong_return_type.stderr
+++ b/axum-macros/tests/debug_handler/fail/wrong_return_type.stderr
@@ -9,10 +9,10 @@ error[E0277]: the trait bound `bool: IntoResponse` is not satisfied
             &'static [u8]
             &'static str
             ()
+            (R,)
             (Response<()>, R)
             (Response<()>, T1, R)
             (Response<()>, T1, T2, R)
-            (Response<()>, T1, T2, T3, R)
           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
diff --git a/axum/CHANGELOG.md b/axum/CHANGELOG.md
index 7bb8bd590b..4489c191c6 100644
--- a/axum/CHANGELOG.md
+++ b/axum/CHANGELOG.md
@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
-- None.
+- **added:** Implement `IntoResponse` for `(R,) where R: IntoResponse` ([#2143])
+
+[#2143]: https://github.com/tokio-rs/axum/pull/2143
 
 # 0.6.20 (03. August, 2023)