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    #include <iostream>
 
    template <typename T, typename FT>
    void test( const FT & (T::*ptr)() const )
    {
        std::cout << "const exists" << std::endl;
    }
 
    template <typename T, typename FT>
    void test( FT & (T::*ptr)() )
    {
        std::cout << "non-const exists" << std::endl;
    }
 
 
    struct A {
        const double & a() const { return a_; }
        double & a() { return a_; }
 
        private:
            double a_;
    };
 
    struct B {
        const double & b() const { return b_; }
 
        private:
            double b_;
    };
 
 
 
    int main( int argc, char **argv )
    {
        test(&A::a);
        test(&B::b);
 
        return 0;
    }
 

prog.cpp: In function ‘int main(int, char**)’:
prog.cpp:35: error: call of overloaded ‘test(<unresolved overloaded function type>)’ is ambiguous
prog.cpp:4: note: candidates are: void test(const FT& (T::*)()const) [with T = A, FT = double]
prog.cpp:10: note:                 void test(FT& (T::*)()) [with T = A, FT = double]

Standard output is empty