Qt: Return value of signal works, why is the official doc saying it is impossible / forbidden?

Question

Qt documentation says, return values of signals are not possible:

Signals are automatically generated by the moc and must not be implemented in the

Answer 1

The problem is that the return types are are not checked for compatibility at connect-time, thus connecting a double-returning slot to a float-returning signal, say, will overflow the stack (no pun intended) space allocated to the float.