RD_RESOLVED
apy->type = RD_RESOLVED;
apx->type = RD_RESOLVED;
apx->type==RD_RESOLVED ||
apy->type==RD_RESOLVED ||
case RD_RESOLVED:
assert( ap1->type==REDUCE || ap1->type==RD_RESOLVED || ap1->type==CONFLICT);
assert( ap2->type==REDUCE || ap2->type==RD_RESOLVED || ap2->type==CONFLICT);
apy->type = RD_RESOLVED;
apy->type = RD_RESOLVED; /* associativity */