Compiler Error C2875

using-declaration causes a multiple declaration of 'class::identifier'

Your using-declaration is incorrect because it would cause the same item to be defined twice.

For example, the following code shows an incorrect using declaration.

class A {
public:
   int z;
};

class B : public A {
   using A::z;
   using A::z; // C2875, A::z defined more than once
};