change synthetic sender’s reply type to UnknownDoNotWriteMeDown

akka-channels/src/main/scala/akka/channels/Ops.scala

@@ -14,6 +14,14 @@ sealed trait TNil extends ChannelList
 sealed trait :+:[A <: (_, _), B <: ChannelList] extends ChannelList
 sealed trait ReplyChannels[T <: ChannelList] extends ChannelList
 
+/**
+ * This type is used to stand in for the unknown reply types of the fabricated
+ * sender references; users don’t need to write it down, and if they do, they
+ * know that they’re cheating (since these ref types must not escape their 
+ * defining actor context).
+ */
+sealed trait UnknownDoNotWriteMeDown
+
 class ActorRefOps(val ref: ActorRef) extends AnyVal {
   import macros.Helpers._
   def narrow[C <: ChannelList](implicit timeout: Timeout, ec: ExecutionContext, tt: ru.TypeTag[C]): Future[ChannelRef[C]] = {

akka-channels/src/main/scala/akka/channels/macros/Ask.scala

@@ -31,7 +31,7 @@ object Ask {
 
     Tell.verify(c)(null, unwrapped, typeOf[(Any, Nothing) :+: TNil], tpeChannel)
 
-    implicit val ttReturnChannels = c.TypeTag[ReturnChannels](toChannels(c.universe)(out))
+    implicit val ttReturnChannels = c.TypeTag[ReturnChannels](toChannels(c.universe)(out, weakTypeOf[Nothing]))
     implicit val ttReturnLUB = c.TypeTag[ReturnLUB](c.universe.lub(out))
     reify(askOps[WrappedMessage[ReturnChannels, ReturnLUB]](
       c.prefix.splice.actorRef, toMsg(c)(msg, tpeMsg).splice)(imp[Timeout](c).splice))
@@ -54,7 +54,7 @@ object Ask {
 
     Tell.verify(c)(null, unwrapped, typeOf[(Any, Nothing) :+: TNil], tpeChannel)
 
-    implicit val ttReturnChannels = c.TypeTag[ReturnChannels](toChannels(c.universe)(out))
+    implicit val ttReturnChannels = c.TypeTag[ReturnChannels](toChannels(c.universe)(out, weakTypeOf[Nothing]))
     implicit val ttReturnLUB = c.TypeTag[ReturnLUB](c.universe.lub(out))
     val msg = reify(c.prefix.splice.value)
     reify(askOps[WrappedMessage[ReturnChannels, ReturnLUB]](
@@ -78,7 +78,7 @@ object Ask {
 
     Tell.verify(c)(null, unwrapped, typeOf[(Any, Nothing) :+: TNil], tpeChannel)
 
-    implicit val ttReturnChannels = c.TypeTag[ReturnChannels](toChannels(c.universe)(out))
+    implicit val ttReturnChannels = c.TypeTag[ReturnChannels](toChannels(c.universe)(out, weakTypeOf[Nothing]))
     implicit val ttReturnLUB = c.TypeTag[ReturnLUB](c.universe.lub(out))
     if (tpeMsg <:< typeOf[ChannelList])
       reify(askFutureWrapped[WrappedMessage[ReturnChannels, ReturnLUB]](

akka-channels/src/main/scala/akka/channels/macros/Channel.scala

@@ -34,7 +34,7 @@ object Channel {
       checkUnique(c.universe)(tpeMsgT, tpeMyChannels) foreach (c.error(c.enclosingPosition, _))
       // need to calculate the intersection of the reply channel sets for all input channels
       val intersection = inputChannels(c.universe)(tpeMsgT) map (replyChannels(c.universe)(tpeMyChannels, _).toSet) reduce (_ intersect _)
-      val channels = toChannels(c.universe)(intersection.toList)
+      val channels = toChannels(c.universe)(intersection.toList, weakTypeOf[UnknownDoNotWriteMeDown])
       implicit val ttMyChannels = c.TypeTag[MyChannels](tpeMyChannels)
       implicit val ttReplyChannels = c.TypeTag[ReplyChannels](channels)
       implicit val ttMsgT = c.TypeTag[MsgT](tpeMsgT)

akka-channels/src/main/scala/akka/channels/macros/Helpers.scala

@@ -117,7 +117,7 @@ object Helpers {
    * convert a list of types List(<T1>, <T2>, ...) into a ChannelList
    * ( Channel[<T1>, Nothing] :=: Channel[<T2>, Nothing] :=: ... :=: TNil )
    */
-  final def toChannels(u: Universe)(list: List[u.Type]): u.Type = {
+  final def toChannels(u: Universe)(list: List[u.Type], out: u.Type): u.Type = {
     import u._
     def rec(l: List[Type], acc: Type): Type = l match {
       case head :: (tail: List[Type]) ⇒
@@ -127,7 +127,7 @@ object Helpers {
             appliedType(weakTypeOf[:+:[_, _]].typeConstructor, List(
               appliedType(weakTypeOf[Tuple2[_, _]].typeConstructor, List(
                 head,
-                weakTypeOf[Nothing])),
+                out)),
               acc)))
       case _ ⇒ acc
     }

akka-channels/src/main/scala/akka/channels/macros/Tell.scala

@@ -70,15 +70,18 @@ object Tell {
   }
 
   def verify(c: Context)(sender: c.universe.Tree, msgT: c.universe.Type, sndT: c.universe.Type, chT: c.universe.Type)(): Unit = {
+    val unknown = c.universe.weakTypeOf[UnknownDoNotWriteMeDown]
+    val nothing = c.universe.weakTypeOf[Nothing]
+    def ignoreUnknown(in: c.universe.Type): c.universe.Type = if (in =:= unknown) nothing else in
     def rec(msg: Set[c.universe.Type], checked: Set[c.universe.Type], depth: Int): Unit =
       if (msg.nonEmpty) {
         val u: c.universe.type = c.universe
-        val replies = msg map (m ⇒ m -> replyChannels(u)(chT, m))
+        val replies = msg map (m ⇒ m -> (replyChannels(u)(chT, m) map (t => ignoreUnknown(t))))
         val missing = replies collect { case (k, v) if v.size == 0 ⇒ k }
         if (missing.nonEmpty)
           error(c, s"target ChannelRef does not support messages of types ${missing mkString ", "} (at depth $depth)")
         else {
-          val nextSend = replies.map(_._2).flatten map (m ⇒ m -> replyChannels(u)(sndT, m))
+          val nextSend = replies.map(_._2).flatten map (m ⇒ m -> (replyChannels(u)(sndT, m) map (t => ignoreUnknown(t))))
           val nextMissing = nextSend collect { case (k, v) if v.size == 0 ⇒ k }
           if (nextMissing.nonEmpty)
             error(c, s"implicit sender `$sender` does not support messages of the reply types ${nextMissing mkString ", "} (at depth $depth)")