private static class LitVal {
final Object canonValue;
final List<AncestorChain<Literal>> uses = Lists.newArrayList();
LitVal(AncestorChain<Literal> useAc) {
Literal use = useAc.node;
canonValue = use instanceof StringLiteral
? ((StringLiteral) use).getUnquotedValue() : use.getValue();
}