Is it possible to use Macro to derive codecs for traits (not sealed traits)? If not, how do I make one myself?

Suppose the following:

trait Foo

case class Bar(foos: List[Foo])

case class Foo1(int: Int) extends Foo

case class Foo2(string: String) extends Foo

val bar = Bar(List(Foo1(42), Foo2("foo2")))

If I register the registry and codec like this:

val registry = fromRegistries(fromProviders(classOf[Bar], classOf[Foo], classOf[Foo1], classOf[Foo2]), DEFAULT_MONGO_REGISTRY)
val codec = registry.get(classOf[Bar])

Then I am able to encode (i.e. turn bar into a BsonDocument, but not decode - it will fail with next on empty iterator on FooMacroCodec$1.getClassName.

Is there a way to do this? I've simplified my code a lot, in reality I simply cannot turn Foo into a sealed trait.

Thanks in advance.