create a new object CI4

Hi, in PHP the actual name for an empty class are this.

PHP Code:

$this->model = new stdClass(); 


The problem is in php 7.4

PHP Code:

new stdClass(); 


the error is:

Class 'App\Controllers\stdObject' not found


I read that for php write:
(object) Null;
or
new stdClass ();
it's the same thing.

But I don't understand why he can't find the class.
i don't know if i have to add use something \\ other \\ object functions

Thanks