Laravel, Class controller does not exist in route with prefixes

Namespace in group (or callback) don't work (Lumen, Laravel)? I want to remove the code from routes.php to controllers. And so!

use App\Http\Controllers;

// OK!
$app->get('path', 'BarController@getId');

$app->group(['prefix' => 'foo'], function ($app) {
// OK!
$app->get('path', '\App\Http\Controllers\BarController@getId');

// Class BarController does not exist
$app->get('path', 'BarController@getId');
});

For your `use` statement to work, you'll have to use the `::class` syntax:

<!-- language: lang-php -->

use App\Http\Controllers\BarController;

$app->get('path', BarController::class.'@getId');

Alternatively, you can add the namespace to your group:

<!-- language: lang-php -->

$app->group(['prefix' => 'foo', 'namespace' => 'App\Http\Controllers'], function ($app) {
$app->get('path', 'BarController@getId');
});