How's this for a radical thought --- optional<T> should not be assignable from T. That way, it doesn't matter whether T is a reference, or not. Instead, to change the binding, use reset(), and to assign use *. optional<int> x; x.reset(3); // x now holds the value 3 x.reset(4); // x now holds a new int, value 4 *x=5; // change the value of the held int, to 5 x.reset(); // x now empty x=6; // error, no direct assignment x=optional<int>(6); // now holds a new int, value 6 struct NonAssignable { const int value; NonAssignable(int value_): value(value_) {} }; optional<NonAssignable> y; y.reset(NonAssignable(3)); // ok y.reset(NonAssignable(4)); // y now holds a new NonAssignable, value 4 *y=NonAssignable(5); // error, NonAssignable doesn't support assignment y.reset(); // y now empty y=NonAssignable(6); // error, no direct assignment y=optional<NonAssignable>(NonAssignable(6)); // now holds a new NonAssignable int a=1; int b=2; int c=3; optional<int&> z; z.reset(a); // ok --- reference to a z.reset(b); // ok --- reference to b *z=c; // assign 3 to b y.reset(); y=c; // error, no direct assignment y=optional<int&>(c); // now holds a ref to c Anthony -- Anthony Williams Software Developer Just Software Solutions Ltd http://www.justsoftwaresolutions.co.uk