Wrong warning on constructor parameter

I got strange warning "Expected parameter of type 'string', 'string' provided"!

on this:

class ServiceContainer extends Container
{

    public function __construct()
    {
        parent::__construct("_services");
    }

the Container class has the constructor __construct(string $home)

The Ide is PHPStorm 2020.2.4 on MacOS Big Sur 11.0.1