I think I figured it out - x is the placeholder for the parameter.
The definition of DEFINE_BOOL_VAL is
#define DEFINE_BOOL_VAL(x) \ private: bool m_b##x; \ public: bool x () { return m_b##x; }
VAX shows same behaviour when you write the implementation of a function (sometimes). So its the icon which is wrong and it should not show it for any USE of a function or macro.