type = NodeType.getNodeType(element);
if (type != NodeType.INTEGER)
report.error(newMsg(tree, bundle, "incorrectElementType")
.put("expected", NodeType.INTEGER)
.put("found", type));
else if (element.bigIntegerValue().compareTo(BigInteger.ONE) < 0)
report.error(newMsg(tree, bundle, "integerIsNegative")
.put("value", element));
uniqueItems = set.add(element);
}