37 template <
class T1, 
class T2, 
class Enable = 
void>
    51 #define DECLARE_PROMOTE(A,B,C)                  \    52     template <> struct promote_trait<A,B>       \    54         typedef C T_promote;                    \    86 DECLARE_PROMOTE(
unsigned long long, 
unsigned long long, 
unsigned long long);
 
DECLARE_PROMOTE(int64_t, bool, int64_t)