QtQuick App Crash - SEGFAULT

class Item: public QObject {
  Q_OBJECT
public:
  int code;
  QString name;
  Q_INVOKABLE int getCode();
  Q_INVOKABLE QString getName();
}

class ItemBox: public QObject {
  Q_OBJECT
private: 
  QList<Item *> items;
public:
  ItemBox() { }
  Q_INVOKABLE void fillBox();
  Q_INVOKABLE int  itemsCount();
  Q_INVOKABLE Item* getItem(int);
}

int Item::getCode() {
  return code;
}
QString Item::getName() {
  return name;
}
void ItemBox::fillBox() { 
  //creating items in heap...
  // and adding them to items list
}

int ItemBox::itemsCount() {
  return items.count();
}

Item* ItemBox::getItem(int index) {
  return items.at(index);
}

Item {
  // --//--//--
  ItemBox {
    id: itemBox
    Component.onCompleted {
      itemBox.fillBox()
    }
  } 
  StackView {
    id: stackView
  }
}

Item {
    Component.onCompleted {
      // print all Items
    for(var i = 0; i < itemBox.itemsCount(); ++i) {
      console.log("Item name: " + itemBox.getItem(i).getName())
      console.log("Item code: " + itemBox.getItem(i).getCode())
    }
}

Item* ItemBox::getItem(int index) {
  Item* item = NULL;
  if (index >= 0 && index < items.count()) {
      item = items.at(index);
  }
  if (!item)
      qFatal("something went wrong...");
  return item;
}

item = items.at(index);

$ qt-everywhere-opensource-src-5.2.1$ grep NULL * -R | wc -l
18849

template <typename T>
inline const T &QList<T>::at(int i) const
{ Q_ASSERT_X(i >= 0 && i < p.size(), "QList<T>::at", "index out of range");
 return reinterpret_cast<Node *>(p.at(i))->t(); }

#ifdef Q_COMPILER_NULLPTR
# define Q_NULLPTR         nullptr
#else
# define Q_NULLPTR         0
#endif