__overflows_type
__overflows_type(n, T))
__TEST_OVERFLOWS_TYPE(__overflows_type, t1, t2, of); \
__TEST_OVERFLOWS_TYPE(__overflows_type, t1, __t2, of); \
__TEST_OVERFLOWS_TYPE(__overflows_type, var++, int, false);
__TEST_OVERFLOWS_TYPE(__overflows_type, var++, int, false);
__TEST_OVERFLOWS_TYPE(__overflows_type, var++, int, true);