This issue is for discussing the use case given in the next section, and the unevaluatedProperties proposal to solve it. If you want to discuss a different use case or a different proposal, you MUST file your own issue to do so. Any comments attempting to revive other lines of discussion from #515, introduce new problems or solutions, or otherwise derail this discussion will be deleted to keep the focus clear. Please file a new issue and link back to this one instead.