import scala.reflect.runtime.universe._ import scala.reflect.runtime.{currentMirror => cm} case class Foo(x: Int) extends AnyVal case class Bar(foo: Foo) object Test extends dotty.runtime.LegacyApp { val foo = typeOf[Bar].decl(TermName("foo")).asMethod println(foo.returnType) // Foo val bar = Bar(Foo(3)) println(bar.foo) // Foo(3) val im = cm.reflect(bar) println(im.reflectField(foo).get) // incorrectly gives java.lang.Integer(3) not Foo(3) im.reflectField(foo).set(Foo(5)) // java.lang.IllegalArgumentException: Can not set int field Bar.foo to Foo println(im.reflectMethod(foo)()) // incorrectly gives java.lang.Integer(3) not Foo(3) }