The following code example is taken from the book
C++ Templates - The Complete Guide
by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002
© Copyright David Vandevoorde and Nicolai M. Josuttis 2002
// partial specialization for two identical types
template<typename T>
class Promotion<T,T> {
public:
typedef T ResultT;
};