$ scala
Welcome to Scala 2.12.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_131).
Type in expressions for evaluation. Or try :help.

scala> val byNameContainer = {
     |     def unwrap[ByName0[_]](f: ByName0[Unit] => Unit): { type ByName[A] = ByName0[A] } = {
     |       new {
     |         type ByName[A] = ByName0[A]
     |       }
     |     }
     |     val f: (=> Unit) => Unit = { _ =>
     |       ()
     |     }
     |     unwrap(f)
     |   }
<console>:12: warning: higher-kinded type should be enabled
by making the implicit value scala.language.higherKinds visible.
This can be achieved by adding the import clause 'import scala.language.higherKinds'
or by setting the compiler option -language:higherKinds.
See the Scaladoc for value scala.language.higherKinds for a discussion
why the feature should be explicitly enabled.
           def unwrap[ByName0[_]](f: ByName0[Unit] => Unit): { type ByName[A] = ByName0[A] } = {
                      ^
byNameContainer: AnyRef{type ByName[A] = => A} = $anon$1@598260a6

scala> 

scala>   type ByName[A] = byNameContainer.ByName[A]
defined type alias ByName

scala> 

scala>   trait RefinementFunction {
     |     type Parameter
     | 
     |     def apply(parameter: Parameter): Unit
     |   }
defined trait RefinementFunction

scala> 

scala>   val f = new RefinementFunction {
     |     type Parameter = ByName[String];
     |     def apply(v1: => String): Unit = {}
     |   }
f: RefinementFunction{type Parameter = ByName[String]} = $anon$1@5cb042da

scala>   
     | f("x")
java.lang.AbstractMethodError: $anon$1.apply(Ljava/lang/Object;)V
  ... 30 elided