Type safe state inheritance (#1532)

* Make state type safe

* fix examples

* remove unnecessary `#[track_caller]`s

* Router::into_service -> Router::with_state

* fixup docs

* macro docs

* add missing docs

* fix examples

* format

* changelog

* Update trybuild tests

* Make sure fallbacks are still inherited for opaque services (#1540)

* Document nesting routers with different state

* fix leftover conflicts

axum-macros/tests/from_request/pass/container.rs

@@ -3,7 +3,6 @@ use axum::{
     extract::{FromRequest, Json},
     response::Response,
 };
-use axum_macros::FromRequest;
 use serde::Deserialize;
 
 #[derive(Deserialize, FromRequest)]

axum-macros/tests/from_request/pass/container_parts.rs

@@ -2,7 +2,6 @@ use axum::{
     extract::{FromRequestParts, Extension},
     response::Response,
 };
-use axum_macros::FromRequestParts;
 
 #[derive(Clone, FromRequestParts)]
 #[from_request(via(Extension))]

axum-macros/tests/from_request/pass/named.rs

@@ -4,7 +4,6 @@ use axum::{
     response::Response,
     headers::{self, UserAgent},
 };
-use axum_macros::FromRequest;
 
 #[derive(FromRequest)]
 struct Extractor {

axum-macros/tests/from_request/pass/named_parts.rs

@@ -3,7 +3,6 @@ use axum::{
     headers::{self, UserAgent},
     response::Response,
 };
-use axum_macros::FromRequestParts;
 
 #[derive(FromRequestParts)]
 struct Extractor {

axum-macros/tests/from_request/pass/named_via.rs

@@ -7,7 +7,6 @@ use axum::{
     },
     headers::{self, UserAgent},
 };
-use axum_macros::FromRequest;
 
 #[derive(FromRequest)]
 struct Extractor {

axum-macros/tests/from_request/pass/named_via_parts.rs

@@ -6,7 +6,6 @@ use axum::{
     },
     headers::{self, UserAgent},
 };
-use axum_macros::FromRequestParts;
 
 #[derive(FromRequestParts)]
 struct Extractor {

axum-macros/tests/from_request/pass/override_rejection.rs

@@ -6,7 +6,6 @@ use axum::{
     routing::get,
     Extension, Router,
 };
-use axum_macros::FromRequest;
 
 fn main() {
     let _: Router = Router::new().route("/", get(handler).post(handler_result));

axum-macros/tests/from_request/pass/override_rejection_parts.rs

@@ -6,7 +6,6 @@ use axum::{
     routing::get,
     Extension, Router,
 };
-use axum_macros::FromRequestParts;
 
 fn main() {
     let _: Router = Router::new().route("/", get(handler).post(handler_result));

axum-macros/tests/from_request/pass/state_enum_via.rs

@@ -6,9 +6,10 @@ use axum::{
 use axum_macros::FromRequest;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
+    let _: axum::routing::RouterService = Router::new()
         .route("/a", get(|_: AppState| async {}))
-        .route("/b", get(|_: InnerState| async {}));
+        .route("/b", get(|_: InnerState| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(Clone, FromRequest)]

axum-macros/tests/from_request/pass/state_enum_via_parts.rs

@@ -6,10 +6,11 @@ use axum::{
 use axum_macros::FromRequestParts;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
+    let _: axum::routing::RouterService = Router::new()
         .route("/a", get(|_: AppState| async {}))
         .route("/b", get(|_: InnerState| async {}))
-        .route("/c", get(|_: AppState, _: InnerState| async {}));
+        .route("/c", get(|_: AppState, _: InnerState| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(Clone, FromRequestParts)]

axum-macros/tests/from_request/pass/state_explicit.rs

@@ -6,8 +6,9 @@ use axum::{
 };
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
-        .route("/b", get(|_: Extractor| async {}));
+    let _: axum::routing::RouterService = Router::new()
+        .route("/b", get(|_: Extractor| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(FromRequest)]

axum-macros/tests/from_request/pass/state_explicit_parts.rs

@@ -7,8 +7,9 @@ use axum::{
 use std::collections::HashMap;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
-        .route("/b", get(|_: Extractor| async {}));
+    let _: axum::routing::RouterService = Router::new()
+        .route("/b", get(|_: Extractor| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(FromRequestParts)]

axum-macros/tests/from_request/pass/state_field_explicit.rs

@@ -6,8 +6,9 @@ use axum::{
 use axum_macros::FromRequest;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
-        .route("/", get(|_: Extractor| async {}));
+    let _: axum::routing::RouterService = Router::new()
+        .route("/", get(|_: Extractor| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(FromRequest)]

axum-macros/tests/from_request/pass/state_field_infer.rs

@@ -6,8 +6,9 @@ use axum::{
 use axum_macros::FromRequest;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
-        .route("/", get(|_: Extractor| async {}));
+    let _: axum::routing::RouterService = Router::new()
+        .route("/", get(|_: Extractor| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(FromRequest)]

axum-macros/tests/from_request/pass/state_via.rs

@@ -6,9 +6,10 @@ use axum::{
 use axum_macros::FromRequest;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
+    let _: axum::routing::RouterService = Router::new()
         .route("/b", get(|_: (), _: AppState| async {}))
-        .route("/c", get(|_: (), _: InnerState| async {}));
+        .route("/c", get(|_: (), _: InnerState| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(Clone, Default, FromRequest)]

axum-macros/tests/from_request/pass/state_via_infer.rs

@@ -6,8 +6,9 @@ use axum::{
 use axum_macros::FromRequest;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
-        .route("/b", get(|_: AppState| async {}));
+    let _: axum::routing::RouterService = Router::new()
+        .route("/b", get(|_: AppState| async {}))
+        .with_state(AppState::default());
 }
 
 // if we're extract "via" `State<AppState>` and not specifying state

axum-macros/tests/from_request/pass/state_via_parts.rs

@@ -6,10 +6,11 @@ use axum::{
 use axum_macros::FromRequestParts;
 
 fn main() {
-    let _: Router<AppState> = Router::with_state(AppState::default())
+    let _: axum::routing::RouterService = Router::new()
         .route("/a", get(|_: AppState, _: InnerState, _: String| async {}))
         .route("/b", get(|_: AppState, _: String| async {}))
-        .route("/c", get(|_: InnerState, _: String| async {}));
+        .route("/c", get(|_: InnerState, _: String| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(Clone, Default, FromRequestParts)]

axum-macros/tests/from_request/pass/state_with_rejection.rs

@@ -8,8 +8,9 @@ use axum::{
 use axum_macros::FromRequest;
 
 fn main() {
-    let _: Router<AppState> =
-        Router::with_state(AppState::default()).route("/a", get(|_: Extractor| async {}));
+    let _: axum::routing::RouterService = Router::new()
+        .route("/a", get(|_: Extractor| async {}))
+        .with_state(AppState::default());
 }
 
 #[derive(Clone, Default, FromRequest)]