diff --git a/axum/src/handler/into_service_state_in_extension.rs b/axum/src/handler/into_service_state_in_extension.rs
deleted file mode 100644
index 61f7ed43..00000000
--- a/axum/src/handler/into_service_state_in_extension.rs
+++ /dev/null
@@ -1,84 +0,0 @@
-use super::Handler;
-use crate::response::Response;
-use http::Request;
-use std::{
-    convert::Infallible,
-    fmt,
-    marker::PhantomData,
-    task::{Context, Poll},
-};
-use tower_service::Service;
-
-pub(crate) struct IntoServiceStateInExtension<H, T, S, B> {
-    handler: H,
-    _marker: PhantomData<fn() -> (T, S, B)>,
-}
-
-#[test]
-fn traits() {
-    use crate::test_helpers::*;
-    assert_send::<IntoServiceStateInExtension<(), NotSendSync, (), NotSendSync>>();
-    assert_sync::<IntoServiceStateInExtension<(), NotSendSync, (), NotSendSync>>();
-}
-
-impl<H, T, S, B> IntoServiceStateInExtension<H, T, S, B> {
-    pub(crate) fn new(handler: H) -> Self {
-        Self {
-            handler,
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<H, T, S, B> fmt::Debug for IntoServiceStateInExtension<H, T, S, B> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("IntoServiceStateInExtension")
-            .finish_non_exhaustive()
-    }
-}
-
-impl<H, T, S, B> Clone for IntoServiceStateInExtension<H, T, S, B>
-where
-    H: Clone,
-{
-    fn clone(&self) -> Self {
-        Self {
-            handler: self.handler.clone(),
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<H, T, S, B> Service<Request<B>> for IntoServiceStateInExtension<H, T, S, B>
-where
-    H: Handler<T, S, B> + Clone + Send + 'static,
-    B: Send + 'static,
-    S: Send + Sync + 'static,
-{
-    type Response = Response;
-    type Error = Infallible;
-    type Future = super::future::IntoServiceFuture<H::Future>;
-
-    #[inline]
-    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        // `IntoServiceStateInExtension` can only be constructed from async functions which are always ready, or
-        // from `Layered` which buffers in `<Layered as Handler>::call` and is therefore
-        // also always ready.
-        Poll::Ready(Ok(()))
-    }
-
-    fn call(&mut self, mut req: Request<B>) -> Self::Future {
-        use futures_util::future::FutureExt;
-
-        let state = req
-            .extensions_mut()
-            .remove::<S>()
-            .expect("state extension missing. This is a bug in axum, please file an issue");
-
-        let handler = self.handler.clone();
-        let future = Handler::call(handler, req, state);
-        let future = future.map(Ok as _);
-
-        super::future::IntoServiceFuture::new(future)
-    }
-}