Method validate does not exist - Laravel 5.4 : <p>I have a very weird problem. When I'm submitting the form, it throws an error with server-side validation.</p>

<p>Here is my simple controller:</p>

<pre><code>namespace App\Http\Controllers;

use Newsletter;
use Illuminate\Http\Request;

class SubscriptionController extends Controller
{
    public function subscribe(Request $request)
    {
        $request-&gt;validate([
            'email' =&gt; 'required|email',
            ]);
    }
}
</code></pre>

<p>Submitting the form gives me:</p>

<blockquote>
  <p>BadMethodCallException
  Method validate does not exist.</p>
</blockquote>

<p>it should work according to:</p>

<p><a href="https://laravel.com/docs/5.4/validation" rel="noreferrer">https://laravel.com/docs/5.4/validation</a></p>
