Created attachment 244768 [details]
Example header and settings.

I have something like the following (slightly odd, but legitimate C++11 (according to gcc at least) and the reason for it is more apparent in the full code):

/*! \brief This class is documented.*/
class ABaseClass {
public:
    bool operator==(const ABaseClass& arhs) const noexcept;
    bool operator!=(const ABaseClass& arhs) const noexcept;
    bool operator<(const ABaseClass& arhs) const noexcept;
    bool operator<=(const ABaseClass& arhs) const noexcept;
    bool operator>(const ABaseClass& arhs) const noexcept;
    bool operator>=(const ABaseClass& arhs) const noexcept;
};

/*! \brief This class is documented.*/
class ADerivedClass : public ABaseClass {
public:
    using ABaseClass::operator==;
    using ABaseClass::operator!=;
    using ABaseClass::operator<;
    using ABaseClass::operator<=;
    using ABaseClass::operator>;
    using ABaseClass::operator>=;
};


Doygen gives the following warnings:

demodox.hpp:21: Warning: documented symbol `typedef ADerivedClass::ABaseClass::operator' was not declared or defined.
demodox.hpp:22: Warning: documented symbol `typedef ADerivedClass::ABaseClass::operator' was not declared or defined.
demodox.hpp:24: Warning: documented symbol `typedef ADerivedClass::ABaseClass::operator' was not declared or defined.
demodox.hpp:26: Warning: documented symbol `typedef ADerivedClass::ABaseClass::operator' was not declared or defined.

Notice that it complains about only four of the six using statements (==, !=, <=, >=).  It causes no actual problems that I can see, just the unwanted warnings.

Example header and settings file in attachment.  Settings use EXTRACT_ALL=YES to avoid having to add unnecessary documentation to the example).