diff --git a/axum-extra/src/routing/typed.rs b/axum-extra/src/routing/typed.rs
index 22c93c56..8191e175 100644
--- a/axum-extra/src/routing/typed.rs
+++ b/axum-extra/src/routing/typed.rs
@@ -150,6 +150,9 @@ pub trait TypedPath: std::fmt::Display {
     /// The path with optional captures such as `/users/:id`.
     const PATH: &'static str;
 
+    /// The parameter types this path requires.
+    type Parameters;
+
     /// Convert the path into a `Uri`.
     ///
     /// # Panics
diff --git a/axum-macros/src/typed_path.rs b/axum-macros/src/typed_path.rs
index b1416c8b..84609c80 100644
--- a/axum-macros/src/typed_path.rs
+++ b/axum-macros/src/typed_path.rs
@@ -21,9 +21,9 @@ pub(crate) fn expand(item_struct: ItemStruct) -> syn::Result<TokenStream> {
     let Attrs { path } = parse_attrs(attrs)?;
 
     match fields {
-        syn::Fields::Named(_) => {
+        syn::Fields::Named(fields) => {
             let segments = parse_path(&path)?;
-            Ok(expand_named_fields(ident, path, &segments))
+            Ok(expand_named_fields(ident, fields, path, &segments))
         }
         syn::Fields::Unnamed(fields) => {
             let segments = parse_path(&path)?;
@@ -63,14 +63,23 @@ fn parse_attrs(attrs: &[syn::Attribute]) -> syn::Result<Attrs> {
     })
 }
 
-fn expand_named_fields(ident: &syn::Ident, path: LitStr, segments: &[Segment]) -> TokenStream {
+fn expand_named_fields(
+    ident: &syn::Ident,
+    fields: &syn::FieldsNamed,
+    path: LitStr,
+    segments: &[Segment],
+) -> TokenStream {
     let format_str = format_str_from_path(segments);
     let captures = captures_from_path(segments);
 
+    let params = fields.named.iter().map(|field| &field.ty);
+
     let typed_path_impl = quote_spanned! {path.span()=>
         #[automatically_derived]
         impl ::axum_extra::routing::TypedPath for #ident {
             const PATH: &'static str = #path;
+
+            type Parameters = (#(#params,)*);
         }
     };
 
@@ -156,10 +165,14 @@ fn expand_unnamed_fields(
     let format_str = format_str_from_path(segments);
     let captures = captures_from_path(segments);
 
+    let params = fields.unnamed.iter().map(|field| &field.ty);
+
     let typed_path_impl = quote_spanned! {path.span()=>
         #[automatically_derived]
         impl ::axum_extra::routing::TypedPath for #ident {
             const PATH: &'static str = #path;
+
+            type Parameters = (#(#params,)*);
         }
     };
 
@@ -224,6 +237,8 @@ fn expand_unit_fields(ident: &syn::Ident, path: LitStr) -> syn::Result<TokenStre
         #[automatically_derived]
         impl ::axum_extra::routing::TypedPath for #ident {
             const PATH: &'static str = #path;
+
+            type Parameters = ();
         }
     };
 
diff --git a/axum-openapi/Cargo.toml b/axum-openapi/Cargo.toml
index 732a19c6..d35ccbef 100644
--- a/axum-openapi/Cargo.toml
+++ b/axum-openapi/Cargo.toml
@@ -7,3 +7,10 @@ edition = "2021"
 axum = { path = "../axum", version = "0.4" }
 okapi = "0.7.0-rc.1"
 schemars = "0.8.8"
+mime = "0.3.16"
+
+serde_json = "1.0"
+
+[dev-dependencies]
+assert-json-diff = "2.0"
+serde = { version = "1.0", features = ["derive"] }
diff --git a/axum-openapi/src/describe_request.rs b/axum-openapi/src/describe_request.rs
new file mode 100644
index 00000000..ab2c11d4
--- /dev/null
+++ b/axum-openapi/src/describe_request.rs
@@ -0,0 +1,91 @@
+use axum::{
+    body::HttpBody,
+    extract::FromRequest,
+    handler::Handler,
+    http::{Request, StatusCode},
+    response::{IntoResponse, Response},
+    routing::{self, MethodRouter},
+    Json, Router,
+};
+use okapi::openapi3::{
+    self, Components, Info, MediaType, OpenApi, Operation, Parameter, RefOr, RequestBody,
+};
+use schemars::{
+    schema::{RootSchema, Schema},
+    JsonSchema,
+};
+use std::{
+    collections::BTreeMap, convert::Infallible, future::Future, marker::PhantomData, sync::Arc,
+};
+
+pub trait DescribeRequest {
+    fn describe(operation: &mut Operation, components: &mut Components);
+}
+
+impl DescribeRequest for () {
+    fn describe(_: &mut Operation, _: &mut Components) {}
+}
+
+macro_rules! impl_tuples {
+    ( $($ty:ident),* $(,)? ) => {
+        impl<$($ty,)*> DescribeRequest for ($($ty,)*)
+        where
+            $($ty: DescribeRequest,)*
+        {
+            fn describe(operation: &mut Operation, components: &mut Components) {
+                $( $ty::describe(operation, components); )*
+            }
+        }
+    };
+}
+
+all_the_tuples!(impl_tuples);
+
+impl<T> DescribeRequest for Json<T>
+where
+    T: JsonSchema,
+{
+    fn describe(operation: &mut Operation, components: &mut Components) {
+        let RootSchema {
+            mut schema,
+            definitions,
+            meta_schema: _,
+        } = schemars::schema_for!(T);
+
+        components.schemas.extend(
+            definitions
+                .into_iter()
+                .filter_map(|(k, schema)| match schema {
+                    Schema::Bool(_) => None,
+                    Schema::Object(obj) => Some((k, obj)),
+                }),
+        );
+
+        schema.object().properties = std::mem::take(&mut schema.object().properties)
+            .into_iter()
+            .map(|(key, schema)| match schema {
+                Schema::Bool(_) => (key, schema),
+                Schema::Object(mut obj) => {
+                    if let Some(reference) = &mut obj.reference {
+                        *reference = reference.replace("/definitions/", "/components/schemas/");
+                    }
+                    (key, Schema::Object(obj))
+                }
+            })
+            .collect();
+
+        let request_body = RequestBody {
+            content: schemars::Map::from_iter([(
+                mime::APPLICATION_JSON.to_string(),
+                MediaType {
+                    schema: Some(schema),
+                    ..Default::default()
+                },
+            )]),
+            required: true,
+            ..Default::default()
+        };
+
+        operation.request_body = Some(RefOr::Object(request_body));
+    }
+}
diff --git a/axum-openapi/src/describe_response.rs b/axum-openapi/src/describe_response.rs
new file mode 100644
index 00000000..43ff1f12
--- /dev/null
+++ b/axum-openapi/src/describe_response.rs
@@ -0,0 +1,74 @@
+use axum::{
+    body::HttpBody,
+    extract::FromRequest,
+    handler::Handler,
+    http::{Request, StatusCode},
+    response::{IntoResponse, Response},
+    routing::{self, MethodRouter},
+    Json, Router,
+};
+use okapi::openapi3::{
+    self, Components, Info, MediaType, OpenApi, Operation, Parameter, RefOr, RequestBody,
+};
+use schemars::{
+    schema::{RootSchema, Schema},
+    JsonSchema,
+};
+use std::{
+    collections::BTreeMap, convert::Infallible, future::Future, marker::PhantomData, sync::Arc,
+};
+
+pub trait DescribeResponse {
+    fn describe(operation: &mut Operation, components: &mut Components);
+}
+
+impl DescribeResponse for () {
+    fn describe(operation: &mut Operation, components: &mut Components) {
+        Ok::describe(operation, components)
+    }
+}
+
+macro_rules! impl_tuples {
+    ( $($ty:ident),* $(,)? ) => {
+        impl<$($ty,)*> DescribeResponse for ($($ty,)*)
+        where
+            $($ty: DescribeResponse,)*
+        {
+            fn describe(operation: &mut Operation, components: &mut Components) {
+                $( $ty::describe(operation, components); )*
+            }
+        }
+    };
+}
+
+all_the_tuples!(impl_tuples);
+
+macro_rules! status {
+    (
+        $name:ident, $variant:ident
+    ) => {
+        #[derive(Copy, Clone)]
+        pub struct $name;
+
+        impl IntoResponse for $name {
+            fn into_response(self) -> Response {
+                StatusCode::$variant.into_response()
+            }
+        }
+
+        impl DescribeResponse for $name {
+            fn describe(operation: &mut Operation, _: &mut Components) {
+                operation.responses.responses.insert(
+                    StatusCode::$variant.as_u16().to_string(),
+                    RefOr::Object(openapi3::Response {
+                        description: "Successful response".to_owned(),
+                        ..Default::default()
+                    }),
+                );
+            }
+        }
+    };
+}
+
+status!(Ok, OK);
+status!(Created, CREATED);
diff --git a/axum-openapi/src/lib.rs b/axum-openapi/src/lib.rs
index 1a4b4655..6b4e67c8 100644
--- a/axum-openapi/src/lib.rs
+++ b/axum-openapi/src/lib.rs
@@ -1,16 +1,57 @@
-#![allow(missing_debug_implementations)]
+#![allow(missing_debug_implementations, dead_code, unused_imports)]
+#![deny(unreachable_pub)]
 
 use axum::{
-    async_trait,
     body::HttpBody,
+    extract::FromRequest,
     handler::Handler,
-    http::Request,
+    http::{Request, StatusCode},
     response::{IntoResponse, Response},
-    routing::{get, post},
-    Router,
+    routing::{self, MethodRouter},
+    Json, Router,
+};
+use okapi::openapi3::{
+    self, Components, Info, MediaType, OpenApi, Operation, Parameter, RefOr, RequestBody,
+};
+use schemars::{
+    schema::{RootSchema, Schema},
+    JsonSchema,
+};
+use std::{
+    collections::BTreeMap, convert::Infallible, future::Future, marker::PhantomData, sync::Arc,
+};
+
+#[macro_use]
+mod macros {
+    macro_rules! all_the_tuples {
+        ($name:ident) => {
+            $name!(T1);
+            $name!(T1, T2);
+            $name!(T1, T2, T3);
+            $name!(T1, T2, T3, T4);
+            $name!(T1, T2, T3, T4, T5);
+            $name!(T1, T2, T3, T4, T5, T6);
+            $name!(T1, T2, T3, T4, T5, T6, T7);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15);
+            $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16);
+        };
+    }
+}
+
+mod describe_request;
+mod describe_response;
+
+pub use self::{
+    describe_request::DescribeRequest,
+    describe_response::{Created, DescribeResponse, Ok},
 };
-use okapi::openapi3::{Info, OpenApi, Operation};
-use std::{future::Future, marker::PhantomData, sync::Arc};
 
 pub struct OpenApiRouter<B> {
     router: Router<B>,
@@ -26,129 +67,276 @@ where
             router: Default::default(),
             schema: OpenApi {
                 info,
+                openapi: "3.0.0".to_owned(),
+                components: Some(Components::default()),
                 ..Default::default()
             },
         }
     }
 
-    pub fn get<H, T>(mut self, path: &str, handler: H) -> Self
-    where
-        H: OpenApiHandler<T, B>,
-        T: 'static,
-    {
-        let mut operation = Operation::default();
-        handler.clone().to_operation(&mut operation);
-        self.schema.paths.entry(path.to_owned()).or_default().get = Some(operation);
-        self.router = self.router.route(path, get(handler));
-        self
+    pub fn into_parts(self) -> (Router<B>, OpenApi) {
+        (self.router, self.schema)
     }
 
-    pub fn post<H, T>(mut self, path: &str, handler: H) -> Self
-    where
-        H: OpenApiHandler<T, B>,
-        T: 'static,
-    {
-        let mut operation = Operation::default();
-        handler.clone().to_operation(&mut operation);
-        self.schema.paths.entry(path.to_owned()).or_default().post = Some(operation);
-        self.router = self.router.route(path, post(handler));
+    pub fn route(mut self, path: &str, handler: OpenApiHandler<B>) -> Self {
+        let OpenApiHandler {
+            svc,
+            method,
+            operation,
+            components,
+        } = handler;
+
+        self.router = self.router.route(path, svc);
+
+        extend_components(self.schema.components.as_mut().unwrap(), components);
+
+        let path = path
+            .split('/')
+            .map(|segment| {
+                if let Some(param) = segment.strip_prefix(':') {
+                    format!("{{{}}}", param)
+                } else {
+                    // TODO(david): wildcards
+                    segment.to_owned()
+                }
+            })
+            .collect::<Vec<_>>()
+            .join("/");
+
+        let path_item = self.schema.paths.entry(path).or_default();
+        match method {
+            Method::Get => path_item.get = Some(operation),
+            Method::Post => path_item.post = Some(operation),
+        }
+
         self
     }
 }
 
-pub trait OpenApiHandler<T, B>: Handler<T, B> {
-    fn to_operation(self, operation: &mut Operation);
+fn extend_components(current: &mut Components, new: Components) {
+    let Components {
+        schemas,
+        responses,
+        parameters,
+        examples,
+        request_bodies,
+        headers,
+        security_schemes,
+        links,
+        callbacks,
+        extensions,
+    } = current;
 
-    fn map_operation<F>(self, f: F) -> MapOperation<Self, T, B, F>
+    schemas.extend(new.schemas);
+    responses.extend(new.responses);
+    parameters.extend(new.parameters);
+    examples.extend(new.examples);
+    request_bodies.extend(new.request_bodies);
+    headers.extend(new.headers);
+    security_schemes.extend(new.security_schemes);
+    links.extend(new.links);
+    callbacks.extend(new.callbacks);
+    extensions.extend(new.extensions);
+}
+
+macro_rules! method {
+    ($fn_name:ident, $method:ident) => {
+        pub fn $fn_name<H, T, B>(handler: H) -> OpenApiHandler<B>
+        where
+            H: Handler<T, B> + HandlerResponse<T>,
+            T: DescribeRequest + 'static,
+            H::Response: DescribeResponse,
+            B: Send + 'static,
+        {
+            let mut operation = Operation::default();
+            let mut components = Components::default();
+            T::describe(&mut operation, &mut components);
+            H::Response::describe(&mut operation, &mut components);
+            OpenApiHandler {
+                svc: routing::$fn_name(handler),
+                method: Method::$method,
+                operation,
+                components,
+            }
+        }
+    };
+}
+
+method!(get, Get);
+method!(post, Post);
+
+// TODO(david): the remaining methods
+enum Method {
+    Get,
+    Post,
+}
+
+pub struct OpenApiHandler<B> {
+    svc: MethodRouter<B, Infallible>,
+    method: Method,
+    operation: Operation,
+    components: Components,
+}
+
+impl<B> OpenApiHandler<B> {
+    pub fn operation_id<S>(self, id: S) -> Self
     where
-        F: FnOnce(&mut Operation),
+        S: Into<String>,
     {
-        MapOperation {
-            handler: self,
-            f,
-            _marker: PhantomData,
+        self.map_operation(|op, _| {
+            op.operation_id = Some(id.into());
+        })
+    }
+
+    pub fn summary<S>(self, summary: S) -> Self
+    where
+        S: Into<String>,
+    {
+        self.map_operation(|op, _| {
+            op.summary = Some(summary.into());
+        })
+    }
+
+    pub fn description<S>(self, description: S) -> Self
+    where
+        S: Into<String>,
+    {
+        self.map_operation(|op, _| {
+            op.description = Some(description.into());
+        })
+    }
+
+    pub fn map_operation<F>(mut self, f: F) -> Self
+    where
+        F: FnOnce(&mut Operation, &mut Components),
+    {
+        f(&mut self.operation, &mut self.components);
+        self
+    }
+}
+
+pub trait HandlerResponse<T> {
+    type Response;
+}
+
+impl<F, Fut> HandlerResponse<()> for F
+where
+    F: FnOnce() -> Fut,
+    Fut: Future,
+{
+    type Response = Fut::Output;
+}
+
+macro_rules! impl_tuples {
+    ( $($ty:ident),* $(,)? ) => {
+        impl<F, Fut, $($ty,)*> HandlerResponse<($($ty,)*)> for F
+        where
+            F: FnOnce($($ty,)*) -> Fut,
+            Fut: Future,
+        {
+            type Response = Fut::Output;
         }
-    }
+    };
 }
 
-pub struct MapOperation<H, T, B, F> {
-    handler: H,
-    f: F,
-    _marker: PhantomData<(T, B)>,
-}
-
-impl<H, T, B, F> Clone for MapOperation<H, T, B, F>
-where
-    H: Clone,
-    F: Clone,
-{
-    fn clone(&self) -> Self {
-        Self {
-            handler: self.handler.clone(),
-            f: self.f.clone(),
-            _marker: PhantomData,
-        }
-    }
-}
-
-impl<H, T, B, F> OpenApiHandler<T, B> for MapOperation<H, T, B, F>
-where
-    H: OpenApiHandler<T, B> + Handler<T, B>,
-    F: FnOnce(&mut Operation) + Clone + Send + 'static,
-    T: Send + 'static,
-    B: Send + 'static,
-{
-    fn to_operation(self, operation: &mut Operation) {
-        (self.f)(operation);
-    }
-}
-
-impl<H, T, B, F> Handler<T, B> for MapOperation<H, T, B, F>
-where
-    H: Handler<T, B>,
-    F: Clone + Send + 'static,
-    T: Send + 'static,
-    B: Send + 'static,
-{
-    type Future = H::Future;
-
-    fn call(self, req: Request<B>) -> Self::Future {
-        self.handler.call(req)
-    }
-}
-
-impl<F, Fut, Res, B> OpenApiHandler<(), B> for F
-where
-    F: FnOnce() -> Fut + Clone + Send + 'static,
-    Fut: Future<Output = Res> + Send,
-    Res: IntoResponse,
-    B: Send + 'static,
-{
-    fn to_operation(self, operation: &mut Operation) {
-        todo!()
-    }
-}
+all_the_tuples!(impl_tuples);
 
 #[cfg(test)]
 mod tests {
     use super::*;
+    use assert_json_diff::assert_json_eq;
     use axum::body::Body;
+    use serde::Deserialize;
+    use serde_json::json;
 
     #[test]
     fn test_something() {
+        #[derive(Deserialize, JsonSchema)]
+        struct UsersCreate {
+            account: Account,
+        }
+
+        #[derive(Deserialize, JsonSchema)]
+        struct Account {
+            username: String,
+        }
+
         async fn users_show() {}
 
-        async fn users_create() {}
+        async fn users_create(Json(_): Json<UsersCreate>) -> Created {
+            Created
+        }
 
-        let _router: OpenApiRouter<Body> = OpenApiRouter::new(Info::default())
-            .post(
-                "/users",
-                users_create
-                    .map_operation(|_| {})
-                    .map_operation(|mut operation| {
-                        operation.summary = Some("Create a new user".to_owned());
-                    }),
-            )
-            .get("/users/:id", users_show.map_operation(|_operation| {}));
+        let (router, schema) = OpenApiRouter::<Body>::new(Info::default())
+            .route("/users/:id", get(users_show).operation_id("users_show"))
+            .route("/users", post(users_create).operation_id("users_create"))
+            .into_parts();
+
+        assert_json_eq!(
+            schema,
+            json!({
+                "openapi": "3.0.0",
+                "info": {
+                    "title": "",
+                    "version": ""
+                },
+                "paths": {
+                    "/users": {
+                        "post": {
+                            "operationId": "users_create",
+                            "requestBody": {
+                                "content": {
+                                    "application/json": {
+                                        "schema": {
+                                            "title": "UsersCreate",
+                                            "type": "object",
+                                            "required": [
+                                                "account",
+                                            ],
+                                            "properties": {
+                                                "account": {
+                                                    "$ref": "#/components/schemas/Account"
+                                                }
+                                            }
+                                        }
+                                    }
+                                },
+                                "required": true
+                            },
+                            "responses": {
+                                "201": {
+                                    "description": "Successful response",
+                                }
+                            }
+                        }
+                    },
+                    "/users/{id}": {
+                        "get": {
+                            "operationId": "users_show",
+                            "responses": {
+                                "200": {
+                                    "description": "Successful response",
+                                }
+                            }
+                        }
+                    }
+                },
+                "components": {
+                    "schemas": {
+                        "Account": {
+                            "type": "object",
+                            "required": [
+                                "username"
+                            ],
+                            "properties": {
+                                "username": {
+                                    "type": "string"
+                                }
+                            }
+                        }
+                    }
+                }
+            }),
+        );
     }
 }
diff --git a/axum/src/handler/future.rs b/axum/src/handler/future.rs
index d126dd76..61e939a6 100644
--- a/axum/src/handler/future.rs
+++ b/axum/src/handler/future.rs
@@ -2,7 +2,11 @@
 
 use crate::response::Response;
 use futures_util::future::Map;
-use std::convert::Infallible;
+use http::Request;
+use pin_project_lite::pin_project;
+use std::{convert::Infallible, future::Future, pin::Pin, task::Context};
+use tower::util::Oneshot;
+use tower_service::Service;
 
 opaque_future! {
     /// The response future for [`IntoService`](super::IntoService).
@@ -12,3 +16,36 @@ opaque_future! {
             fn(Response) -> Result<Response, Infallible>,
         >;
 }
+
+pin_project! {
+    /// The response future for [`Layered`](super::Layered).
+    pub struct LayeredFuture<S, ReqBody>
+    where
+        S: Service<Request<ReqBody>>,
+    {
+        #[pin]
+        inner: Map<Oneshot<S, Request<ReqBody>>, fn(Result<S::Response, S::Error>) -> Response>,
+    }
+}
+
+impl<S, ReqBody> LayeredFuture<S, ReqBody>
+where
+    S: Service<Request<ReqBody>>,
+{
+    pub(super) fn new(
+        inner: Map<Oneshot<S, Request<ReqBody>>, fn(Result<S::Response, S::Error>) -> Response>,
+    ) -> Self {
+        Self { inner }
+    }
+}
+
+impl<S, ReqBody> Future for LayeredFuture<S, ReqBody>
+where
+    S: Service<Request<ReqBody>>,
+{
+    type Output = Response;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> std::task::Poll<Self::Output> {
+        self.project().inner.poll(cx)
+    }
+}
diff --git a/axum/src/handler/mod.rs b/axum/src/handler/mod.rs
index e39ea8ca..8b8f0735 100644
--- a/axum/src/handler/mod.rs
+++ b/axum/src/handler/mod.rs
@@ -99,6 +99,7 @@ pub use self::into_service::IntoService;
 ///
 /// See the [module docs](crate::handler) for more details.
 pub trait Handler<T, B = Body>: Clone + Send + Sized + 'static {
+    /// The type of future calling this handler returns.
     type Future: Future<Output = Response> + Send + 'static;
 
     /// Call the handler with the given request.
@@ -334,15 +335,18 @@ where
     ResBody: HttpBody<Data = Bytes> + Send + 'static,
     ResBody::Error: Into<BoxError>,
 {
-    type Future = Pin<Box<dyn Future<Output = Response> + Send + 'static>>;
+    type Future = future::LayeredFuture<S, ReqBody>;
 
     fn call(self, req: Request<ReqBody>) -> Self::Future {
-        Box::pin(async move {
-            match self.svc.oneshot(req).await {
+        use futures_util::future::{FutureExt, Map};
+
+        let future: Map<_, fn(Result<S::Response, S::Error>) -> _> =
+            self.svc.oneshot(req).map(|result| match result {
                 Ok(res) => res.map(boxed),
                 Err(res) => res.into_response(),
-            }
-        })
+            });
+
+        future::LayeredFuture::new(future)
     }
 }
 
diff --git a/axum/src/macros.rs b/axum/src/macros.rs
index d26cc87c..5cdeb88f 100644
--- a/axum/src/macros.rs
+++ b/axum/src/macros.rs
@@ -1,5 +1,3 @@
-//! Internal macros
-
 macro_rules! opaque_future {
     ($(#[$m:meta])* pub type $name:ident = $actual:ty;) => {
         opaque_future! {