输入之后会报错，提示如下：

PHP Fatal error: Uncaught ReflectionException: Class config does not exist in /Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php:752

Stack trace:

/Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(752): ReflectionClass->__construct('config')

/Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(631): Illuminate\Container\Container->build('config')

/Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(586): Illuminate\Container\Container->resolve('config', Array)

/Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(721): Illuminate\Container\Container->make('config', Array)

/Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(1195): Illuminate\Foundation\Application->make('config')

/Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Support/ServiceProvider.php(57): Illuminate\Container\Container->offsetGet('config')

/ in /Users/abc/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 752