if (e instanceof Reference) {
return Operation.createInfix(
Operator.MEMBER_ACCESS, new Reference(new Identifier(UNK, lhs)), e);
} else {
Operation op = (Operation) e;
List<? extends Expression> operands = op.children();
return Operation.create(
e.getFilePosition(), op.getOperator(),
withTopRef(operands.get(0), lhs), operands.get(1));
}
}