This macro indicates that we have all the needed features for an implementation of the type‐switch facility that is source‐compatible with the pre‐existing C++03 facility. The main change is that the numbered classes Switch0‐Switch9 are no longer distinct classes, but aliases of specific instantiations of the primary Switch template. Eventually these partial template specializations will be eliminated, when the individually named members are no longer used throughout the whole of the Bloomberg codebase.