ReplacingBasicValue current = local(var);
// if local var is set, then transfer to it to the existing holders in the local position.
if (current != null) {
if (oldToNew.get(current.getIndex()).iden() == from.iden()) {
int targetFirst = oldToNew.get(current.index).first();
from.transfer(this, targetFirst);
return;
}
}
// if local var is not set, then check map to see if existing holders are mapped to local var.