Safe ZIO.serviceWith

SafeServiceWith.scala

trait ZIO[-R, +E, +A] {
  
}

object ZIO {

  def serviceWithZIO[S]: SWZIOP[S] = new SWZIOP[S]

  def serviceWith[S]: SWP[S] = new SWP[S]
  
}

trait NotZIO[A]

trait NotZIOLP {
  implicit def ok[A]: NotZIO[A] = new NotZIO[A] {}
}

object NotZIO extends NotZIOLP {
  implicit def notok1[R, E, A]: NotZIO[ZIO[R, E, A]] = new NotZIO[ZIO[R, E, A]] {}
  implicit def notok2[R, E, A]: NotZIO[ZIO[R, E, A]] = new NotZIO[ZIO[R, E, A]] {}
}

class SWZIOP[S] {
  def apply[R, E, A](f: S => ZIO[R, E, A]): ZIO[R with S, E, A] = {
    new ZIO[R with S, E, A] {}
  }  
}

class SWP[S] {
  def apply[A](f: S => A)(implicit ev: NotZIO[A]): ZIO[Any, Nothing, A] = {
    new ZIO[Any, Nothing, A] {}
  }  
}

trait Foo {
  def bar: ZIO[Any, Nothing, Unit]
  def baz: String
}

ZIO.serviceWithZIO[Foo](_.bar) // ok
ZIO.serviceWith[Foo](_.baz)    // ok
ZIO.serviceWith[Foo](_.bar)    // ambiguous implicit

println("OK")