Iterator jtr = module.hedgeRules.iterator();
while(jtr.hasNext()) {
HedgeRules hr = (HedgeRules)jtr.next();
if(!hr.exported) continue;
ExportedHedgeRuleChecker ehrc = new ExportedHedgeRuleChecker(module);
if(!hr.visit( ehrc )) {
// this hedgeRule directly/indirectly references exported labels.
// report it to the user.
// TODO: source information?