Getting type tags for type parameters to type constructors

innerTypeTags.scala

  import scala.reflect._
  import scala.reflect.api._

  def innerTypeTags[A: TypeTag]: List[TypeTag[_]] = {
    val typeParams = typeTag[A].tpe match {
      case TypeRef(_, _, args) => args
    }

    typeParams map { tpe =>
      TypeTag(typeTag[A].mirror, new TypeCreator {
        override def apply[U <: Universe with Singleton](m: scala.reflect.api.Mirror[U]): U # Type =
          if (m eq typeTag[A].mirror) tpe.asInstanceOf[U#Type] else sys.error("Wrong mirror")
      })
    }
  }

  innerTypeTags[List[Int]] // List[reflect.runtime.universe.TypeTag[_]] = List(TypeTag[Int])
  innerTypeTags[Map[Int, String]] // List[reflect.runtime.universe.TypeTag[_]] = List(TypeTag[Int], TypeTag[String])