Hi Alexei, > You can get around that error by doing: > this->elems another possibility would be to add a using-declaration - especially, if you are using "elems" more than once in the derived class template<class A> class Derived: public Base<typename A::value_type> { using Base<typename A::value_type>::elems; void Test() { if (elems) { } } }; HTH, Axel