trait Generic[T] { type Repr } object Generic { type Aux[T, Repr0] = Generic[T] { type Repr = Repr0 } import scala.language.experimental.macros implicit def materializeGeneric[T]: Generic[T] = macro Macros.impl[T] } object Test extends App { case class C(x: Int, y: Int) import scala.reflect.runtime.universe._ def reprify[T, Repr](x: T)(implicit generic: Generic.Aux[T, Repr], tag: WeakTypeTag[Repr]) = println(tag) reprify(C(40, 2)) // this is a compilation error at the moment as explained in SI-8104 // because matchesPt in implicit search says that depoly() isn't a subtype of Generic.Aux[C, (Int, Int)] // which is rightfully so, because depoly only replaces type parameters, not type members with wildcard types // however in the future we might want to relax the matchesPt check, so this might start compiling // therefore, if you've broken this test, then you should be happy, because most likely you've just enabled an interesting use case! implicitly[Generic.Aux[C, (Int, Int)]] }