Fatal error: Uncaught ReflectionException: Class log does not exist in Laravel

Have you ever encounter this error when developing your app in Laravel 5 or maybe Laravel 4? If you do, well, you’re not alone.

After few hours debugging and searching for the solution, I found out that you cannot use any Laravel helper functions in your config file. For examples:

<?php 
// /config/sample.php

return [ 
    'image_description' => trans('image.description'),
    'home_url' => url('/'),
];

The codes will cause Fatal error: Uncaught ReflectionException: Class log does not exist in your application.  If you found any other reason, please do let me know.