Yes I was referring to org.apache.lucene.document.FieldType. To add on Emmanuel's thoughts on embedded id, it's correct I wouldn't be able to use FieldType for those, as this type is restricted to having only one per field name in each Document instance.

+1 for specific restrictions on Faceting. We really expect people to use our DSL in this case so that would be easier to change down the road.

So considering that range-queries should be transparently migrated, we should focus on some validation for "exact term" queries not matching the expected type. If that's not doable, that's sad but at some point users will need to face it so it might as well be now.