static ImmutableSet<ObjectType> withDeclaredProperty(
     Set<ObjectType> objs, QualifiedName qname, JSType type, boolean isConstant) {
   ImmutableSet.Builder<ObjectType> newObjs = ImmutableSet.builder();
   for (ObjectType obj : objs) {
     newObjs.add(obj.withPropertyHelper(qname, type, true, isConstant));
   }
   return newObjs.build();
 }