Goetas\Xsd\XsdToPhp\Php\PhpConverter::handleClassExtension PHP Method

    private function handleClassExtension(PHPClass $class, Type $type)
    {
        if ($alias = $this->getTypeAlias($type)) {
            $c = PHPClass::createFromFQCN($alias);
            $val = new PHPProperty('__value');
            $val->setType($c);
            $c->addProperty($val);
            $class->setExtends($c);
        } else {
            $extension = $this->visitType($type, true);
            $class->setExtends($extension);
        }
    }