env.messages.error(SYNTAX, tree, "dc.tag.unknown", tagName);
}
@Override
public Void visitValue(ValueTree tree, Void ignore) {
ReferenceTree ref = tree.getReference();
if (ref == null || ref.getSignature().isEmpty()) {
if (!isConstant(env.currElement))
env.messages.error(REFERENCE, tree, "dc.value.not.allowed.here");
} else {
Element e = env.trees.getElement(new DocTreePath(getCurrentPath(), ref));
if (!isConstant(e))