When doing MyClass* const& as a signal/slot parameter then the 'const&' part is not stripped from the generated code as it would in case of 'MyClass const&' parameter.

MOC strips a reference to constant in the following expression:

void mySlot( MyClass const& );
becomes: "mySlot(MyClass)\0"

while not in the following expression:
void mySlot( MyClass* const& );
becomes: "mySlot(MyClass*const&)\0"

hence in the 2nd scenario, a
connect( mySender, SIGNAL( mySig( MyClass* ) ), myReceiver, SLOT(mySlot( MyClass* ) ) )
will not be possible since the parameter list doesn't match.