Incorrect overload resolution for 2-argument functions

Question

Let\'s take the following example program:

#include 

namespace half_float
{
    template struct half_expr {};

    struct hal         


        

Answer 1

A workaround is to specialise _Common_float_type for half and half_expr to be an undefined type, so that SFINAE gets rid of the VS2012 version of atan2.

namespace std {
    template
    struct _Common_float_type, half_float::half_expr>;
    template
    struct _Common_float_type>;
    template
    struct _Common_float_type, half_float::half>;
    template<>
    struct _Common_float_type;
}

Note that you have to specialise for all four combinations of half and half_expr, because template specialisation doesn't consider base classes.