feat: add #[diagnostic::on_unimplemented] to IntoResponse and IntoResponseParts (#3723)

axum-core/src/response/into_response.rs

@@ -109,6 +109,9 @@ use std::{
 /// let app = Router::new().route("/", get(|| async { MyBody }));
 /// # let _: Router = app;
 /// ```
+#[diagnostic::on_unimplemented(
+    note = "See `https://docs.rs/axum/0.8/axum/response/trait.IntoResponse.html` for details"
+)]
 pub trait IntoResponse {
     /// Create a response.
     #[must_use]

axum-core/src/response/into_response_parts.rs

@@ -70,6 +70,9 @@ use std::{convert::Infallible, fmt};
 ///     SetHeader("x-foo", "custom")
 /// }
 /// ```
+#[diagnostic::on_unimplemented(
+    note = "See `https://docs.rs/axum/0.8/axum/response/trait.IntoResponseParts.html` for details"
+)]
 pub trait IntoResponseParts {
     /// The type returned in the event of an error.
     ///

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

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `bool: FromRequest<(), axum_core::extract::private
  --> tests/debug_handler/fail/argument_not_extractor.rs:4:24
   |
 4 | async fn handler(_foo: bool) {}
-  |                        ^^^^ the trait `FromRequestParts<()>` is not implemented for `bool`, which is required by `bool: FromRequest<(), _>`
+  |                        ^^^^ the trait `FromRequestParts<()>` is not implemented for `bool`
   |
   = note: Function argument is not a valid axum extractor.
           See `https://docs.rs/axum/0.8/axum/extract/index.html` for details

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

@@ -2,7 +2,7 @@ error[E0277]: the trait bound `NonCloneType: Clone` is not satisfied
  --> tests/debug_handler/fail/extension_not_clone.rs:7:38
   |
 7 | async fn test_extension_non_clone(_: Extension<NonCloneType>) {}
-  |                                      ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `NonCloneType`, which is required by `Extension<NonCloneType>: FromRequest<(), _>`
+  |                                      ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `NonCloneType`
   |
   = help: the following other types implement trait `FromRequest<S, M>`:
             Body

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

@@ -2,8 +2,13 @@ error[E0277]: the trait bound `Struct: serde::Deserialize<'de>` is not satisfied
  --> tests/debug_handler/fail/json_not_deserialize.rs:7:24
   |
 7 | async fn handler(_foo: Json<Struct>) {}
-  |                        ^^^^^^^^^^^^ the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `Struct`, which is required by `Json<Struct>: FromRequest<()>`
+  |                        ^^^^^^^^^^^^ unsatisfied trait bound
   |
+help: the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `Struct`
+ --> tests/debug_handler/fail/json_not_deserialize.rs:4:1
+  |
+4 | struct Struct {}
+  | ^^^^^^^^^^^^^
   = note: for local types consider adding `#[derive(serde::Deserialize)]` to your `Struct` type
   = note: for types from other crates check whether the crate offers a `serde` feature flag
   = help: the following other types implement trait `serde_core::de::Deserialize<'de>`:
@@ -18,7 +23,6 @@ error[E0277]: the trait bound `Struct: serde::Deserialize<'de>` is not satisfied
           and $N others
   = note: required for `Struct` to implement `serde_core::de::DeserializeOwned`
   = note: required for `Json<Struct>` to implement `FromRequest<()>`
-  = help: see issue #48214
 help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
   |
 1 + #![feature(trivial_bounds)]
@@ -28,8 +32,13 @@ error[E0277]: the trait bound `Struct: serde::Deserialize<'de>` is not satisfied
  --> tests/debug_handler/fail/json_not_deserialize.rs:7:24
   |
 7 | async fn handler(_foo: Json<Struct>) {}
-  |                        ^^^^^^^^^^^^ the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `Struct`, which is required by `Json<Struct>: FromRequest<()>`
+  |                        ^^^^^^^^^^^^ unsatisfied trait bound
   |
+help: the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `Struct`
+ --> tests/debug_handler/fail/json_not_deserialize.rs:4:1
+  |
+4 | struct Struct {}
+  | ^^^^^^^^^^^^^
   = note: for local types consider adding `#[derive(serde::Deserialize)]` to your `Struct` type
   = note: for types from other crates check whether the crate offers a `serde` feature flag
   = help: the following other types implement trait `serde_core::de::Deserialize<'de>`:

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

@@ -4,7 +4,7 @@ error: future cannot be sent between threads safely
 3 | #[debug_handler]
   | ^^^^^^^^^^^^^^^^ future returned by `handler` is not `Send`
   |
-  = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`, which is required by `impl Future<Output = ()>: Send`
+  = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `Rc<()>`
 note: future is not `Send` as this value is used across an await
  --> tests/debug_handler/fail/not_send.rs:6:14
   |

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

@@ -1,11 +1,11 @@
 error: Cannot return tuples with more than 17 elements
   --> tests/debug_handler/fail/output_tuple_too_many.rs:4:20
    |
-4  |   async fn handler() -> (
+ 4 |   async fn handler() -> (
    |  ____________________^
-5  | |     axum::http::StatusCode,
+ 5 | |     axum::http::StatusCode,
-6  | |     AppendHeaders<[(axum::http::HeaderName, &'static str); 1]>,
+ 6 | |     AppendHeaders<[(axum::http::HeaderName, &'static str); 1]>,
-7  | |     AppendHeaders<[(axum::http::HeaderName, &'static str); 1]>,
+ 7 | |     AppendHeaders<[(axum::http::HeaderName, &'static str); 1]>,
 ...  |
 23 | |     axum::http::StatusCode,
 24 | | ) {

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

@@ -2,8 +2,14 @@ error[E0277]: the trait bound `NotIntoResponse: IntoResponse` is not satisfied
  --> tests/debug_handler/fail/single_wrong_return_tuple.rs:6:23
   |
 6 | async fn handler() -> (NotIntoResponse) {
-  |                       ^^^^^^^^^^^^^^^^^ the trait `IntoResponse` is not implemented for `NotIntoResponse`
+  |                       ^^^^^^^^^^^^^^^^^ unsatisfied trait bound
   |
+help: the trait `IntoResponse` is not implemented for `NotIntoResponse`
+ --> tests/debug_handler/fail/single_wrong_return_tuple.rs:3:1
+  |
+3 | struct NotIntoResponse;
+  | ^^^^^^^^^^^^^^^^^^^^^^
+  = note: See `https://docs.rs/axum/0.8/axum/response/trait.IntoResponse.html` for details
   = help: the following other types implement trait `IntoResponse`:
             &'static [u8; N]
             &'static [u8]

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

@@ -1,10 +1,10 @@
 error: Handlers cannot take more than 16 arguments. Use `(a, b): (ExtractorA, ExtractorA)` to further nest extractors
   --> tests/debug_handler/fail/too_many_extractors.rs:6:5
    |
-6  | /     _e1: Uri,
+ 6 | /     _e1: Uri,
-7  | |     _e2: Uri,
+ 7 | |     _e2: Uri,
-8  | |     _e3: Uri,
+ 8 | |     _e3: Uri,
-9  | |     _e4: Uri,
+ 9 | |     _e4: Uri,
 ...  |
 21 | |     _e16: Uri,
 22 | |     _e17: Uri,

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

@@ -8,8 +8,14 @@ error[E0277]: the trait bound `CustomIntoResponse: IntoResponseParts` is not sat
   --> tests/debug_handler/fail/wrong_return_tuple.rs:21:5
    |
 21 |     CustomIntoResponse,
-   |     ^^^^^^^^^^^^^^^^^^ the trait `IntoResponseParts` is not implemented for `CustomIntoResponse`
+   |     ^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
    |
+help: the trait `IntoResponseParts` is not implemented for `CustomIntoResponse`
+  --> tests/debug_handler/fail/wrong_return_tuple.rs:12:1
+   |
+12 | struct CustomIntoResponse {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: See `https://docs.rs/axum/0.8/axum/response/trait.IntoResponseParts.html` for details
    = help: the following other types implement trait `IntoResponseParts`:
              ()
              (T1, T2)
@@ -20,18 +26,23 @@ error[E0277]: the trait bound `CustomIntoResponse: IntoResponseParts` is not sat
              (T1, T2, T3, T4, T5, T6, T7)
              (T1, T2, T3, T4, T5, T6, T7, T8)
            and $N others
-   = help: see issue #48214
 help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
    |
-3  + #![feature(trivial_bounds)]
+ 3 + #![feature(trivial_bounds)]
    |
 
 error[E0277]: the trait bound `CustomIntoResponse: IntoResponseParts` is not satisfied
   --> tests/debug_handler/fail/wrong_return_tuple.rs:21:5
    |
 21 |     CustomIntoResponse,
-   |     ^^^^^^^^^^^^^^^^^^ the trait `IntoResponseParts` is not implemented for `CustomIntoResponse`
+   |     ^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
    |
+help: the trait `IntoResponseParts` is not implemented for `CustomIntoResponse`
+  --> tests/debug_handler/fail/wrong_return_tuple.rs:12:1
+   |
+12 | struct CustomIntoResponse {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: See `https://docs.rs/axum/0.8/axum/response/trait.IntoResponseParts.html` for details
    = help: the following other types implement trait `IntoResponseParts`:
              ()
              (T1, T2)

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

@@ -4,6 +4,7 @@ error[E0277]: the trait bound `bool: IntoResponse` is not satisfied
 4 | async fn handler() -> bool {
   |                       ^^^^ the trait `IntoResponse` is not implemented for `bool`
   |
+  = note: See `https://docs.rs/axum/0.8/axum/response/trait.IntoResponse.html` for details
   = help: the following other types implement trait `IntoResponse`:
             &'static [u8; N]
             &'static [u8]

axum-macros/tests/from_request/fail/generic_without_via.stderr

@@ -16,9 +16,12 @@ error[E0277]: the trait bound `fn(Extractor<()>) -> impl Future<Output = ()> {fo
 note: required by a bound in `axum::routing::get`
   --> $WORKSPACE/axum/src/routing/method_routing.rs
    |
+   |             H: Handler<T, S>,
+   |                ^^^^^^^^^^^^^ required by this bound in `get`
+...
    | top_level_handler_fn!(get, GET);
-   | ^^^^^^^^^^^^^^^^^^^^^^---^^^^^^
+   | -------------------------------
    | |                     |
    | |                     required by a bound in this function
-   | required by this bound in `get`
+   | in this macro invocation
    = note: this error originates in the macro `top_level_handler_fn` (in Nightly builds, run with -Z macro-backtrace for more info)

axum-macros/tests/from_request/fail/generic_without_via_rejection.stderr

@@ -16,9 +16,12 @@ error[E0277]: the trait bound `fn(Extractor<()>) -> impl Future<Output = ()> {fo
 note: required by a bound in `axum::routing::get`
   --> $WORKSPACE/axum/src/routing/method_routing.rs
    |
+   |             H: Handler<T, S>,
+   |                ^^^^^^^^^^^^^ required by this bound in `get`
+...
    | top_level_handler_fn!(get, GET);
-   | ^^^^^^^^^^^^^^^^^^^^^^---^^^^^^
+   | -------------------------------
    | |                     |
    | |                     required by a bound in this function
-   | required by this bound in `get`
+   | in this macro invocation
    = note: this error originates in the macro `top_level_handler_fn` (in Nightly builds, run with -Z macro-backtrace for more info)

axum-macros/tests/from_request/fail/override_rejection_on_enum_without_via.stderr

@@ -16,28 +16,35 @@ error[E0277]: the trait bound `fn(MyExtractor) -> impl Future<Output = ()> {hand
 note: required by a bound in `axum::routing::get`
   --> $WORKSPACE/axum/src/routing/method_routing.rs
    |
+   |             H: Handler<T, S>,
+   |                ^^^^^^^^^^^^^ required by this bound in `get`
+...
    | top_level_handler_fn!(get, GET);
-   | ^^^^^^^^^^^^^^^^^^^^^^---^^^^^^
+   | -------------------------------
    | |                     |
    | |                     required by a bound in this function
-   | required by this bound in `get`
+   | in this macro invocation
    = note: this error originates in the macro `top_level_handler_fn` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0277]: the trait bound `fn(Result<MyExtractor, MyRejection>) -> impl Future<Output = ()> {handler_result}: Handler<_, _>` is not satisfied
   --> tests/from_request/fail/override_rejection_on_enum_without_via.rs:10:64
    |
 10 |     let _: Router = Router::new().route("/", get(handler).post(handler_result));
-   |                                                           ---- ^^^^^^^^^^^^^^ the trait `Handler<_, _>` is not implemented for fn item `fn(Result<MyExtractor, MyRejection>) -> impl Future<Output = ()> {handler_result}`
+   |                                                           ---- ^^^^^^^^^^^^^^ unsatisfied trait bound
    |                                                           |
    |                                                           required by a bound introduced by this call
    |
+   = help: the trait `Handler<_, _>` is not implemented for fn item `fn(Result<MyExtractor, MyRejection>) -> impl Future<Output = ()> {handler_result}`
    = note: Consider using `#[axum::debug_handler]` to improve the error message
 note: required by a bound in `MethodRouter::<S>::post`
   --> $WORKSPACE/axum/src/routing/method_routing.rs
    |
+   |             H: Handler<T, S>,
+   |                ^^^^^^^^^^^^^ required by this bound in `MethodRouter::<S>::post`
+...
    |     chained_handler_fn!(post, POST);
-   |     ^^^^^^^^^^^^^^^^^^^^----^^^^^^^
+   |     -------------------------------
    |     |                   |
    |     |                   required by a bound in this associated function
-   |     required by this bound in `MethodRouter::<S>::post`
+   |     in this macro invocation
    = note: this error originates in the macro `chained_handler_fn` (in Nightly builds, run with -Z macro-backtrace for more info)

axum-macros/tests/typed_path/fail/missing_capture.stderr

@@ -10,5 +10,9 @@ help: include the missing field in the pattern
   |                       ++++++
 help: if you don't care about this missing field, you can explicitly ignore it
   |
+5 | #[typed_path("/users" { id: _ })]
+  |                       +++++++++
+help: or always ignore missing fields here
+  |
 5 | #[typed_path("/users" { .. })]
   |                       ++++++

axum-macros/tests/typed_path/fail/not_deserialize.stderr

@@ -1,9 +1,39 @@
+error[E0277]: the trait bound `MyPath: serde::de::DeserializeOwned` is not satisfied
+ --> tests/typed_path/fail/not_deserialize.rs:3:10
+  |
+3 | #[derive(TypedPath)]
+  |          ^^^^^^^^^ unsatisfied trait bound
+  |
+help: the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `MyPath`
+ --> tests/typed_path/fail/not_deserialize.rs:5:1
+  |
+5 | struct MyPath {
+  | ^^^^^^^^^^^^^
+  = help: the following other types implement trait `serde_core::de::Deserialize<'de>`:
+            &'a [u8]
+            &'a serde_json::raw::RawValue
+            &'a std::path::Path
+            &'a str
+            ()
+            (T,)
+            (T0, T1)
+            (T0, T1, T2)
+          and $N others
+  = note: required for `MyPath` to implement `serde_core::de::DeserializeOwned`
+  = note: required for `axum::extract::Path<MyPath>` to implement `FromRequestParts<S>`
+  = note: this error originates in the derive macro `TypedPath` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0277]: the trait bound `MyPath: serde::Deserialize<'de>` is not satisfied
  --> tests/typed_path/fail/not_deserialize.rs:3:10
   |
 3 | #[derive(TypedPath)]
-  |          ^^^^^^^^^ the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `MyPath`, which is required by `axum::extract::Path<MyPath>: FromRequestParts<S>`
+  |          ^^^^^^^^^ unsatisfied trait bound
   |
+help: the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `MyPath`
+ --> tests/typed_path/fail/not_deserialize.rs:5:1
+  |
+5 | struct MyPath {
+  | ^^^^^^^^^^^^^
   = note: for local types consider adding `#[derive(serde::Deserialize)]` to your `MyPath` type
   = note: for types from other crates check whether the crate offers a `serde` feature flag
   = help: the following other types implement trait `serde_core::de::Deserialize<'de>`:
@@ -23,8 +53,13 @@ error[E0277]: the trait bound `MyPath: serde::de::DeserializeOwned` is not satis
  --> tests/typed_path/fail/not_deserialize.rs:3:10
   |
 3 | #[derive(TypedPath)]
-  |          ^^^^^^^^^ the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `MyPath`, which is required by `axum::extract::Path<MyPath>: FromRequestParts<S>`
+  |          ^^^^^^^^^ unsatisfied trait bound
   |
+help: the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `MyPath`
+ --> tests/typed_path/fail/not_deserialize.rs:5:1
+  |
+5 | struct MyPath {
+  | ^^^^^^^^^^^^^
   = help: the following other types implement trait `serde_core::de::Deserialize<'de>`:
             &'a [u8]
             &'a serde_json::raw::RawValue
@@ -37,23 +72,3 @@ error[E0277]: the trait bound `MyPath: serde::de::DeserializeOwned` is not satis
           and $N others
   = note: required for `MyPath` to implement `serde_core::de::DeserializeOwned`
   = note: required for `axum::extract::Path<MyPath>` to implement `FromRequestParts<S>`
-
-error[E0277]: the trait bound `MyPath: serde::de::DeserializeOwned` is not satisfied
- --> tests/typed_path/fail/not_deserialize.rs:3:10
-  |
-3 | #[derive(TypedPath)]
-  |          ^^^^^^^^^ the trait `for<'de> serde_core::de::Deserialize<'de>` is not implemented for `MyPath`, which is required by `axum::extract::Path<MyPath>: FromRequestParts<S>`
-  |
-  = help: the following other types implement trait `serde_core::de::Deserialize<'de>`:
-            &'a [u8]
-            &'a serde_json::raw::RawValue
-            &'a std::path::Path
-            &'a str
-            ()
-            (T,)
-            (T0, T1)
-            (T0, T1, T2)
-          and $N others
-  = note: required for `MyPath` to implement `serde_core::de::DeserializeOwned`
-  = note: required for `axum::extract::Path<MyPath>` to implement `FromRequestParts<S>`
-  = note: this error originates in the derive macro `TypedPath` (in Nightly builds, run with -Z macro-backtrace for more info)