Re: [boost] [optional] problems with swap()

Frank Mori Hess:

Maybe it was just my compiler, but I've had problems in the past with member swap functions breaking ADL for swap used inside the class. IIRC, it would find the member swap function and stop there, never doing ADL.

This is standard-conforming. You've forgotten the using std::swap declaration which reenables ADL by making a nonmember visible in the current scope.