Replace HasRoutes with Into<Router> (#819)

* Move `HasRoutes` into axum

* fix doc test

* Just use `Into<Router>`

axum-extra/src/routing/mod.rs

@@ -1,6 +1,6 @@
 //! Additional types for defining routes.
 
-use axum::{body::Body, handler::Handler, Router};
+use axum::{handler::Handler, Router};
 
 mod resource;
 
@@ -17,31 +17,6 @@ pub use self::typed::{FirstElementIs, TypedPath};
 
 /// Extension trait that adds additional methods to [`Router`].
 pub trait RouterExt<B>: sealed::Sealed {
-    /// Add the routes from `T`'s [`HasRoutes::routes`] to this router.
-    ///
-    /// # Example
-    ///
-    /// Using [`Resource`] which implements [`HasRoutes`]:
-    ///
-    /// ```rust
-    /// use axum::{Router, routing::get};
-    /// use axum_extra::routing::{RouterExt, Resource};
-    ///
-    /// let app = Router::new()
-    ///     .with(
-    ///         Resource::named("users")
-    ///             .index(|| async {})
-    ///             .create(|| async {})
-    ///     )
-    ///     .with(
-    ///         Resource::named("teams").index(|| async {})
-    ///     );
-    /// # let _: Router<axum::body::Body> = app;
-    /// ```
-    fn with<T>(self, routes: T) -> Self
-    where
-        T: HasRoutes<B>;
-
     /// Add a typed `GET` route to the router.
     ///
     /// The path will be inferred from the first argument to the handler function which must
@@ -151,13 +126,6 @@ impl<B> RouterExt<B> for Router<B>
 where
     B: axum::body::HttpBody + Send + 'static,
 {
-    fn with<T>(self, routes: T) -> Self
-    where
-        T: HasRoutes<B>,
-    {
-        self.merge(routes.routes())
-    }
-
     #[cfg(feature = "typed-routing")]
     fn typed_get<H, T, P>(self, handler: H) -> Self
     where
@@ -239,20 +207,6 @@ where
     }
 }
 
-/// Trait for things that can provide routes.
-///
-/// Used with [`RouterExt::with`].
-pub trait HasRoutes<B = Body> {
-    /// Get the routes.
-    fn routes(self) -> Router<B>;
-}
-
-impl<B> HasRoutes<B> for Router<B> {
-    fn routes(self) -> Router<B> {
-        self
-    }
-}
-
 mod sealed {
     pub trait Sealed {}
     impl<B> Sealed for axum::Router<B> {}

axum-extra/src/routing/resource.rs

@@ -1,4 +1,3 @@
-use super::HasRoutes;
 use axum::{
     body::Body,
     handler::Handler,
@@ -45,7 +44,7 @@ use tower_service::Service;
 ///         Router::new().route("/featured", get(|| async {})),
 ///     );
 ///
-/// let app = Router::new().with(users);
+/// let app = Router::new().merge(users);
 /// # let _: Router<axum::body::Body> = app;
 /// ```
 #[derive(Debug)]
@@ -182,9 +181,9 @@ where
     }
 }
 
-impl<B> HasRoutes<B> for Resource<B> {
-    fn routes(self) -> Router<B> {
-        self.router
+impl<B> From<Resource<B>> for Router<B> {
+    fn from(resource: Resource<B>) -> Self {
+        resource.router
     }
 }
 
@@ -192,7 +191,6 @@ impl<B> HasRoutes<B> for Resource<B> {
 mod tests {
     #[allow(unused_imports)]
     use super::*;
-    use crate::routing::RouterExt;
     use axum::{extract::Path, http::Method, Router};
     use tower::ServiceExt;
 
@@ -214,7 +212,7 @@ mod tests {
                 Router::new().route("/featured", get(|| async move { "users#featured" })),
             );
 
-        let mut app = Router::new().with(users);
+        let mut app = Router::new().merge(users);
 
         assert_eq!(
             call_route(&mut app, Method::GET, "/users").await,