Hello Andrew! > > >Your code is not ISO 14882 compliant. > > >The specialization needs to be in the A namespace. > > > > I explored the Standart as thoroughly as I could, > > but failed to find any hints specialization must > > be in exactly the same namespace. > > > > Could you please provide me with an excerpt? > >14.7.3 Para 2. Thanks a lot for the link. Looks like it is not about namespace enclosing, it is about namespace identity. So John is 100 percent correct and specialization needs to be exactly in the A. The question is settled. -- Best regards Ilja Golshtein