Codec for ADT do not compile - mongodb

Question

I'm using the scala driver to make IO operations with mongodb. My scala version is 2.11.11 and the mongo db driver is 2.2.0.
I take the example in documentation about ADT :
sealed class Tree
case class Branch(b1: Tree, b2: Tree, value: Int) extends Tree
case class Leaf(value: Int) extends Tree
val codecRegistry = fromRegistries( fromProviders(classOf[Tree]), DEFAULT_CODEC_REGISTRY )
This code didn't compile.
No known subclasses of the sealed class
[error] val codecRegistry = fromRegistries( fromProviders(classOf[Tree]), DEFAULT_CODEC_REGISTRY )
[error] ^
[error] knownDirectSubclasses of Tree observed before subclass Branch registered
[error] knownDirectSubclasses of Tree observed before subclass Leaf registered
Did I miss something ?
Update
Below a complete example of what I'm tring to do.
build.sbt
name := "mongodb-driver-test"
version := "1.0"
scalaVersion := "2.11.11"
libraryDependencies += "org.mongodb.scala" %% "mongo-scala-driver" % "2.2.0"
file Models.scala
import org.mongodb.scala.bson.codecs.{DEFAULT_CODEC_REGISTRY, Macros}
import org.bson.codecs.configuration.CodecRegistries.{fromProviders, fromRegistries}
/**
* Created by alifirat on 02/01/18.
*/
object Models {
sealed class Tree
case class Branch(b1: Tree, b2: Tree, value: Int) extends Tree
case class Leaf(value: Int) extends Tree
val treeCodec = Macros.createCodecProvider[Tree]()
val treeCodecRegistry = fromRegistries( fromProviders(treeCodec), DEFAULT_CODEC_REGISTRY )
}
Then, just do :
sbt compile
You will get :
[error] val treeCodec = Macros.createCodecProvider[Tree]()
[error] ^
[error] knownDirectSubclasses of Tree observed before subclass Branch registered
[error] knownDirectSubclasses of Tree observed before subclass Leaf registered
[error] three errors found
[error] (compile:compileIncremental) Compilation failed
If I change the scala version to 2.12.0, I didn't have any errors at compile time ...

Answer 1

I'm using driver version 2.6.0 and Scala version 2.12.8 and still get the same problem.
My workaround is to remove the keyword sealed in front of that sealed class, compile, put it back, and then compile again. But it's very cumbersome.