The Everything type in pigeons/all_datatypes.dart has a field List<List<bool?>?>? nestedList. In an integration test of the echo API I tried to do a listEquals on the sent and received objects' nestedList items and got:

type 'List<Object?>' is not a subtype of type 'List<bool?>?' in type cast

It looks like we're not correctly reconstructing the nested types in the host->Dart direction. Even just trying to print the object is throwing a cast error.