No warning emitted with `ImplicitConverter` when `language.implicitConversions` is not imported

[Duhemm]

Defining a value of type ImplicitConverter doesn't emit a warning, like it does when defining an implicit conversion when scala.language.implicitConversions is not in scope.

object O {
  implicit def foo(x: Int): String = x.toString // Emits a warning
  implicit val bar: ImplicitConverter[Int, String] = _.toString // No warning
}

Is this intentional?