Keyed archiver doesn't work with structs, and it also probably doesn't work whenevr you start nesting classes. It relies on introspection and dynamic typing for

Keyed archiver doesn't work with structs, and it also probably doesn't work whenevr you start nesting classes. It relies on introspection and dynamic typing for that, which can't work right now with swift. It's one reason they had to rely on compile-time codegen to implement the swift4 equivalent.