express flow.diff

diff --git a/definitions/npm/express_v4.x.x/flow_v0.104.x-/express_v4.x.x.js b/definitions/npm/express_v4.x.x/flow_v0.104.x-/express_v4.x.x.js
index 84393084..7e29c7e3 100644
--- a/definitions/npm/express_v4.x.x/flow_v0.104.x-/express_v4.x.x.js
+++ b/definitions/npm/express_v4.x.x/flow_v0.104.x-/express_v4.x.x.js
@@ -98,13 +98,97 @@ declare class express$Response extends http$ServerResponse mixins express$Reques
 }
 
 declare type express$NextFunction = (err?: ?Error | 'route') => mixed;
-declare type express$Middleware =
-  ((req: express$Request, res: express$Response, next: express$NextFunction) => mixed) |
-  ((error: Error, req: express$Request, res: express$Response, next: express$NextFunction) => mixed);
+declare type express$Middleware<Req: express$Request, Res: express$Response> =
+  ((req: Req, res: Res, next: express$NextFunction) => mixed) |
+  ((error: Error, req: Req, res: Res, next: express$NextFunction) => mixed);
 declare interface express$RouteMethodType<T> {
-  (middleware: express$Middleware): T;
-  (...middleware: Array<express$Middleware>): T;
-  (path: express$Path|express$Path[], ...middleware: Array<express$Middleware>): T;
+  <Req: express$Request, Res: express$Response>(
+    middleware: express$Middleware<Req, Res>,
+  ): T;
+  <
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+  ): T;
+  <
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+  ): T;
+  <
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+    Req4: express$Request,
+    Res4: express$Response,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+  ): T;
+  <Req: express$Request, Res: express$Response>(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req, Res>,
+  ): T;
+  <
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+  ): T;
+  <
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+  ): T;
+  <
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+    Req4: express$Request,
+    Res4: express$Response,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+  ): T;
+  (...middleware: Array<express$Middleware<mixed, mixed>>): T;
+  (
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    ...middleware: Array<express$Middleware<mixed, mixed>>
+  ): T;
 }
 declare class express$Route {
   all: express$RouteMethodType<this>;
@@ -138,22 +222,138 @@ declare class express$Route {
   connect: express$RouteMethodType<this>;
 }
 
-declare class express$Router extends express$Route {
+declare class express$Router<
+  Req: express$Request,
+  Res: express$Response,
+> extends express$Route {
   constructor(options?: express$RouterOptions): void;
   route(path: string): express$Route;
   static (options?: express$RouterOptions): express$Router;
-  use(middleware: express$Middleware): this;
-  use(...middleware: Array<express$Middleware>): this;
-  use(path: express$Path|express$Path[], ...middleware: Array<express$Middleware>): this;
+  use<Req: express$Request, Res: express$Response>(
+    middleware: express$Middleware<Req, Res>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+    Req4: express$Request,
+    Res4: express$Response,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+    Req4: express$Request,
+    Res4: express$Response,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+    ...middlewares: Array<express$Middleware<mixed, mixed>>
+  ): this;
+  use<Req: express$Request, Res: express$Response>(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware: express$Middleware<Req, Res>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+    Req4: express$Request,
+    Res4: express$Response,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+  ): this;
+  use<
+    Req1: express$Request,
+    Res1: express$Response,
+    Req2: express$Request,
+    Res2: express$Response,
+    Req3: express$Request,
+    Res3: express$Response,
+    Req4: express$Request,
+    Res4: express$Response,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+    ...middlewares: Array<express$Middleware<mixed, mixed>>
+  ): this;
   use(path: string, router: express$Router): this;
   handle(req: http$IncomingMessage<>, res: http$ServerResponse, next: express$NextFunction): void;
-  param(
+  param<Req: express$Request>(
     param: string,
     callback: (
-      req: express$Request,
+      req: Req,
       res: express$Response,
       next: express$NextFunction,
-      id: string
+      value: string,
+      paramName: string,
     ) => mixed
   ): void;
   (req: http$IncomingMessage<>, res: http$ServerResponse, next?: ?express$NextFunction): void;
@@ -187,7 +387,10 @@ declare class express$Application extends express$Router mixins events$EventEmit
 declare module 'express' {
   declare export type RouterOptions = express$RouterOptions;
   declare export type CookieOptions = express$CookieOptions;
-  declare export type Middleware = express$Middleware;
+  declare export type Middleware<
+    Req: express$Request,
+    Res: express$Reseponse,
+  > = express$Middleware<Req, Res>;
   declare export type NextFunction = express$NextFunction;
   declare export type RequestParams = express$RequestParams;
   declare export type $Response = express$Response;
@@ -198,7 +401,7 @@ declare module 'express' {
     // If you try to call like a function, it will use this signature
     (): express$Application,
     // `static` property on the function
-    static: (root: string, options?: Object) => express$Middleware,
+    static: <Req: express$Request>(root: string, options?: Object) => express$Middleware<Req>,
     // `Router` property on the function
     Router: typeof express$Router,
     ...
diff --git a/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_overrideUseMethodClassExtension.js b/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_overrideUseMethodClassExtension.js
index 525b9198..1b988935 100644
--- a/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_overrideUseMethodClassExtension.js
+++ b/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_overrideUseMethodClassExtension.js
@@ -14,16 +14,123 @@ declare type test_express$CustomPath = string | RegExp;
 
 declare type test_express$CustomNextFunction = express$NextFunction;
 
-declare type test_express$CustomMiddleware =
-  ((req: test_express$CustomRequest, res: test_express$CustomResponse, next: test_express$CustomNextFunction) => mixed) |
-  ((error: Error, req: test_express$CustomRequest, res: test_express$CustomResponse, next: test_express$CustomNextFunction) => mixed);
-
 declare class test_express$CustomApplication extends express$Application {
   constructor(expressConstructor: () => express$Application): this;
-  use(middleware: test_express$CustomMiddleware): this;
-  use(...middleware: Array<test_express$CustomMiddleware>): this;
-  use(path: test_express$CustomPath|test_express$CustomPath[], ...middleware: Array<test_express$CustomMiddleware>): this;
-  use(path: string, router: express$Router): this;
+  use<Req: test_express$CustomRequest, Res: test_express$CustomResponse>(
+    middleware: express$Middleware<Req, Res>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+    Req3: test_express$CustomRequest,
+    Res3: test_express$CustomResponse,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+    Req3: test_express$CustomRequest,
+    Res3: test_express$CustomResponse,
+    Req4: test_express$CustomRequest,
+    Res4: test_express$CustomResponse,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+    Req3: test_express$CustomRequest,
+    Res3: test_express$CustomResponse,
+    Req4: test_express$CustomRequest,
+    Res4: test_express$CustomResponse,
+  >(
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+    ...middlewares: Array<express$Middleware<mixed, mixed>>
+  ): this;
+  use<Req: test_express$CustomRequest, Res: test_express$CustomResponse>(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware: express$Middleware<Req, Res>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+    Req3: test_express$CustomRequest,
+    Res3: test_express$CustomResponse,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+    Req3: test_express$CustomRequest,
+    Res3: test_express$CustomResponse,
+    Req4: test_express$CustomRequest,
+    Res4: test_express$CustomResponse,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+  ): this;
+  use<
+    Req1: test_express$CustomRequest,
+    Res1: test_express$CustomResponse,
+    Req2: test_express$CustomRequest,
+    Res2: test_express$CustomResponse,
+    Req3: test_express$CustomRequest,
+    Res3: test_express$CustomResponse,
+    Req4: test_express$CustomRequest,
+    Res4: test_express$CustomResponse,
+  >(
+    path: express$Path | $ReadOnlyArray<express$Path>,
+    middleware1: express$Middleware<Req1, Res1>,
+    middleware2: express$Middleware<Req2, Res2>,
+    middleware3: express$Middleware<Req3, Res3>,
+    middleware4: express$Middleware<Req4, Res4>,
+    ...middlewares: Array<express$Middleware<mixed, mixed>>
+  ): this;
 }
 
 // Class Extensions: Test Functions
@@ -31,7 +138,11 @@ function test_express$CustomApplication(
   expressConstructor: () => express$Application
 ) {
   const express = expressConstructor();
-  express.use((req: any, res: any, next: express$NextFunction) => {
+  express.use((
+    req: test_express$CustomRequest,
+    res: test_express$CustomResponse,
+    next: express$NextFunction,
+  ) => {
     // Private Constructor Mutation: Add new properties
     req.foo = 'hello';
     res.bar = 'goodbye';
diff --git a/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_response.js b/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_response.js
index b604c403..3514604e 100644
--- a/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_response.js
+++ b/definitions/npm/express_v4.x.x/flow_v0.104.x-/test_response.js
@@ -27,6 +27,18 @@ app.use(
 );
 app.post("/post-router-callable", router);
 
+// Can set a custom param on request
+app.param('test', (
+  req: express$Request & { testValue: string, ... },
+  res: express$Response,
+  next: express$NextFunction,
+  id: string,
+  paramName: string,
+) => {
+  req.testValue = id;
+  next();
+});
+
 // Can use an express app directly as a server listener
 const httpServer = http.createServer(app);
 httpServer.listen(9000);