Make declaring the same property multiple times an error

If one declares the same Q_PROPERTY multiple times, moc limits itself to a warning. E.g.

class Test : public QObject
{
  Q_OBJECT
  Q_PROPERTY(int foo MEMBER m_foo);
  Q_PROPERTY(int foo MEMBER m_foo);

  int m_foo;
};

Results in moc warning:

main.cpp:10:1: warning: The property 'foo' is defined multiple times in class Test.

IMHO this should be a plain build error. There's no defined sematnics on what happens – which declaration "wins"? What if they conflict on which getters/setters to use?