dc1a1c5821
The problem is that JvmRecord has SOURCE retention Probably, increasing its retention might be a more reliable solution (or in some other way serializing that the class is a record) Just checking supertypes seems like a reasonable approximation: only records kotlin are allowed to extend j.l.Record. But the relevant diagnostic has been added only since 1.4.30, so potentially there could have been exist a non-record class with such supertype compiled by 1.4.20, but this case seems to be ill-formed and marginal anyway. For Java classes, it's irrelevant since they don't have member properties (only synthetic extensions) ^KT-43677 In Progress