ReflectionMethodInvoke

// https://stackoverflow.com/questions/73377269/using-reflection-class-in-php-also-unable-to-access-private-property

class Forbidden
{
    private function doSomething(): void
    {
        echo "Forbidden";
    }
}

$class = new ReflectionClass(Forbidden::class);
$func  = $class->getMethod('doSomething');
$func->invoke(new Forbidden());