In the post A Bite of Template in C++ (1), I mentioned a constraint for template member functions in class that explicit specialization is not allowed. However, I realized there are more constraints on function templates later when I wanted to make two template varients with slightly difference on only one member function. I tried specializing member function template, as well as inheriting a template member function from base class. Both of them failed due to some constraints. Briefly, the constraints are

1. partial specialization is not allowed for function template,
2. using declaration plus template disambiguator is not the right way to inherit a template member function from a template class.