Container.php 729: Class translator does not exists

1) Container.php 729: Class translator does not exists

Steps to reproduce:-
- In your composer.json add "mews/captcha": "2.2"
- Find the providers key in config/app.php and register the Captcha Service Provider

'providers' => [
        // ...
        'Mews\Captcha\CaptchaServiceProvider',
    ]

Upon saving the file, I receive Container.php 729: Class translator does not exists. And if I comment out the provider the error goes away.

2) If I register the CaptchaServiceProvider in the providers and run any artisan command, I receive array_merge(): Argument #2 is not an array

$ php artisan config:clear

In ServiceProvider.php line 59:

  array_merge(): Argument #2 is not an array  

I tried changing the mews/captcha version but no luck there. Feedback would be highly appreciated.

via Chebli Mohamed