class Node: public NodeBase {
    T data;
    NodeBase *parent;
public:
    Node(T);
    void setData(T);
    T * getData(void);
    void setParent(NodeBase * const);
    NodeBase * getParent(void);
};

class NodeBase {
};

Node<char> n1 = Node('A');
Node<int>  n2 = Node(63);
n1.setParent(&n2);

NodeBase *pNode = n1.getParent();
pNode->getData(); // Error: BaseNode has no member 'getData()'