可捕获的致命错误：传递给 Illuminate\Routing\UrlGenerator::__construct() 的参数 2 必须是 Illuminate\Http\Request 的实例，给定 null

当我尝试运行时出现此错误php artisan (anything):

PHP Catchable fatal error:  Argument 2 passed to
Illuminate\Routing\UrlGenerator::__construct()
must be an instance of Illuminate\Http\Request, null given, called in
/www/laravel5/vendor/laravel/framework/src/Illuminate/Routing/RoutingServiceProvider.php
on line 56 and defined in
/www/laravel5/vendor/laravel/framework/src/Illuminate/Routing/UrlGenerator.php
on line 81

Catchable fatal error: Argument 2 passed to
Illuminate\Routing\UrlGenerator::__construct()
must be an instance of Illuminate\Http\Request, null given, called in
/www/laravel5/vendor/laravel/framework/src/Illuminate/Routing/RoutingServiceProvider.php
on line 56 and defined in
/www/laravel5/vendor/laravel/framework/src/Illuminate/Routing/UrlGenerator.php
on line 81

我完全不知道是什么原因造成的，需要帮助。

提前致谢

好吧，我发现了导致错误的原因。

In config/services.php我正在这样做：

'facebook' => [
    'client_id'     => env('FACEBOOK_APP_ID', null),
    'client_secret' => env('FACEBOOK_APP_SECRET', null),
    'redirect'      => url('auth/facebook'),
]

url('auth/facebook')是什么导致了错误。