I am trying the example code from the container of thephpleague found at : https://container.thephpleague.com/4.x/ and what I have is pretty basic IMHO.

Note: PSR-4 auto loading has been configured in composer.json and composer du has been executed.

require __DIR__.'/../vendor/autoload.php';

use AppServiceFooBar;
use AppServiceBar;

$container = new LeagueContainerContainer(); 
$container->add('foobar', FooBar::class)->addArgument(Bar::class);
$container->add('bar', Bar::class);

$foo = $container->get('foobar'); //this line gives an error Uncaught TypeError: AppServiceFooBar::__construct(): Argument #1 ($bar) must be of type AppServiceBar, string given

The classes defined

// file: FooBar.php
namespace AppService;

class FooBar {

    private $bar;

    /**
     * @param AppServiceBar $bar
     */
    public function __construct(Bar $bar) {
        $this->bar = $bar;
        var_dump('Constructor of '. __CLASS__ . ' called!');
    }

    public function getBar() {
        return $this->bar;
    }
}

//file: Bar.php
namespace AppService;

class Bar {
    
    public function __construct() {
        var_dump('Constructor of ' . __CLASS__ . ' called!');
    }
}

If I register the following to the container I don’t get an error.

$container->add(Bar::class);

I am trying to understand what is the problem with the first snippet which comes from the example code.