can() not work for User Model (Laravel 5.1)

https://laravel.com/docs/5.1/authorization#via-the-user-model

Model User must have a trait:

use Illuminate\Foundation\Auth\Access\Authorizable;

Policy Example

<?php

namespace App\Policies;

use Illuminate\Auth\Access\HandlesAuthorization;

use App\User;

class UserPolicy
{
    use HandlesAuthorization;

    /**
     * Create a new policy instance.
     *
     * @return void
     */
    public function __construct()
    {
        //
    }

    public function before($user, $ability){
        if ($user->isSuperAdmin()) {
            return true;
        }
    }

    public function view(User $user){
        if($user->is_admin() == true){
            return true;
        }

        return false;
    }
}

Usage in controller

$user = Auth::user();

// Need to pass $user!
logg($user->can('view', $user));

Reference: