How does Laravel use the app object like its an array?

I am setting up an application in PHP, trying to follow some of the conventions laid down in Laravel, I can see there are lots of references to $this->app["some_var"];

But in my app it throws an error saying "Cannot use object as an array".

I am aware that Laravel uses magic methods such as __get() and __set() which I have included, however I still get the same results.

The magic getter and setter code I have used in the parent class of my App object

  /**
  * Dynamically access container services.
  *
  * @param  string  $key
  * @return mixed
  */
  public function __get($key)
  {
    return $this[$key];
  }

  /**
   * Dynamically set container services.
   *
   * @param  string  $key
   * @param  mixed   $value
   * @return void
   */
  public function __set($key, $value)
  {
    $this[$key] = $value;
  }

Expected result is for it to access any property that is innaccessable on the object?

Currently throws a Fatal error: Uncaught Error: Cannot use object Application as type of array.

via Chebli Mohamed