Laravel Auth Middleware: Class can does not exist

I'm trying to protect a route via middleware as described in the doc

When I hit the url, I get:

ReflectionException in Container.php line 749:
Class can does not exist

Here's the relevant part from routes.php:

Route::get('{user}/profile/edit/{type?}', [
    'as'   => 'edit',
    'uses' => 'User\UserController@edit',
    'middleware' => ['can:edit-user,user'],
]);

AuthServiceProvider.php:

public function boot()
{
    $this->registerPolicies();

    // ... other definitions

    Gate::define('edit-user', function ($user, $subjectUser) {
        return
            $user->hasRole('manage.user') // if the user has this role, green
            ||
            ($user->isAdmin && $user->id == $subjectUser->id) // otherwise if is admin, can edit her own profile
            ;
    });

Maybe it's because I'm not using a separate policy class for defining the gate?

via Attila Fulop