OP_CONCAT
if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
codearith(fs, OP_CONCAT, e1, e2, line);
case OP_CONCAT: tm = TM_CONCAT; break;
case OP_CONCAT: {
vmcase(OP_CONCAT,