Implementing native multi auth (user vs admin) using guards in Laravel 5.5 - guest middle ware uses hard coded named route

I would like to implement native multi authentication in my application for two types of users: User and Admin.

1. I started implementing a new admins table migration (by copying the existing create_users_table).

2. I created a new model called Admin (by copying the existing User model)

3. Both (User and Admin) models were updated to specify which guards they use like this:

User Model

protected $guarded  = ['user'];

Admin Model

protected $guarded  = ['admin'];

4. Then I setup the auth configuration like this:

config/auth.php

https://pastebin.com/iLAZbX2z

5. Then I defined my custom auth routes for users and admins like this:

routes/web.php

https://pastebin.com/raw/CKX9Xddb

6. Finally, I defined the auth protected routes for the two user types like this:

routes/web.php

// User auth protected pages
Route::prefix('manage')->middleware('auth:user')->namespace('Manage')->group(function() {

    Route::get('/', 'DashboardController@index');

});

// Admin auth protected pages
Route::prefix('admin')->middleware('auth:admin')->namespace('Admin')->group(function() {

    Route::get('/', 'DashboardController@index');

});

I tested the user login first before proceeding (there's more to be done to get admin to login), by going into http://myapp.local/login and entering my credentials and I was successfully redirected to user's dashboard (i.e. http://myapp.local/manage). All of the user specific functionality (e.g. reset pass) etc.. are all working fine).

However; when testing the guest middleware by visiting http://myapp.local/manage directly, I expected to be redirected to http://myapp.local/login but got an error instead:

Route [login] not defined.

This error is valid; because in the routes definition, I've named the user login as user.login

It looks like the guest middleware uses a hard coded named route called login in the unauthenticated exception handler.

protected function unauthenticated($request, AuthenticationException $exception)
{
    return $request->expectsJson()
                ? response()->json(['message' => $exception->getMessage()], 401)
                : redirect()->guest(route('login')); // <------
} 

How can I tell the guest middleware to use a differently named route for the login (when un-authenticated user tries to visit a auth protected page)?

I will need to use this later for the admin guest middleware also.

via Chebli Mohamed