Top-level ref of record definitions in lexicons

[yamarten]

According to the Lexicon specification, only object types can be used in the record field of record type. This is in contrast to the ability to use union and ref for schema field of API. Why is it like this?

Simple records, like like and repost, often have exactly the same record, so it is useful to commonize the definition without increasing the nesting. Also, even if the collection is different for each service, you may want to have a compatible record.

Are there any expected problems if the record allows a reference?