TAIL_POS          596 src/vm.c               if (!TAIL_POS()) {                      \
TAIL_POS          885 src/vm.c                           if (TAIL_POS()) RETURN_OP();
TAIL_POS          972 src/vm.c                           if (TAIL_POS()) RETURN_OP();
TAIL_POS          995 src/vm.c                           if (TAIL_POS()) RETURN_OP();