=act #3572 Add parens to sender

* because it is not referentially transparent; normally we reserved parens for
  side-effecting code but given how people thoughtlessly close over it we revised
  that that decision for sender
* caller can still omit parens

akka-actor-tests/src/test/scala/akka/actor/ActorDSLSpec.scala

@@ -26,7 +26,7 @@ class ActorDSLSpec extends AkkaSpec {
 
   val echo = system.actorOf(Props(new Actor {
     def receive = {
-      case x ⇒ sender ! x
+      case x ⇒ sender() ! x
     }
   }))
 
@@ -119,7 +119,7 @@ class ActorDSLSpec extends AkkaSpec {
       //#simple-actor
       val a = actor(new Act {
         become {
-          case "hello" ⇒ sender ! "hi"
+          case "hello" ⇒ sender() ! "hi"
         }
       })
       //#simple-actor
@@ -133,10 +133,10 @@ class ActorDSLSpec extends AkkaSpec {
       //#becomeStacked
       val a = actor(new Act {
         become { // this will replace the initial (empty) behavior
-          case "info" ⇒ sender ! "A"
+          case "info" ⇒ sender() ! "A"
           case "switch" ⇒
             becomeStacked { // this will stack upon the "A" behavior
-              case "info"   ⇒ sender ! "B"
+              case "info"   ⇒ sender() ! "B"
               case "switch" ⇒ unbecome() // return to the "A" behavior
             }
           case "lobotomize" ⇒ unbecome() // OH NOES: Actor.emptyBehavior
@@ -144,7 +144,7 @@ class ActorDSLSpec extends AkkaSpec {
       })
       //#becomeStacked
 
-      implicit def sender = testActor
+      implicit val sender = testActor
       a ! "info"
       expectMsg("A")
       a ! "switch"

akka-actor-tests/src/test/scala/akka/actor/ActorFireForgetRequestReplySpec.scala

@@ -15,9 +15,9 @@ object ActorFireForgetRequestReplySpec {
   class ReplyActor extends Actor {
     def receive = {
       case "Send" ⇒
-        sender ! "Reply"
+        sender() ! "Reply"
       case "SendImplicit" ⇒
-        sender ! "ReplyImplicit"
+        sender() ! "ReplyImplicit"
     }
   }
 

akka-actor-tests/src/test/scala/akka/actor/ActorLifeCycleSpec.scala

@@ -25,7 +25,7 @@ object ActorLifeCycleSpec {
     val currentGen = generationProvider.getAndIncrement()
     override def preStart() { report("preStart") }
     override def postStop() { report("postStop") }
-    def receive = { case "status" ⇒ sender ! message("OK") }
+    def receive = { case "status" ⇒ sender() ! message("OK") }
   }
 
 }
@@ -131,15 +131,15 @@ class ActorLifeCycleSpec extends AkkaSpec("akka.actor.serialize-messages=off") w
       case class Become(recv: ActorContext ⇒ Receive)
       val a = system.actorOf(Props(new Actor {
         def receive = {
-          case Become(beh) ⇒ { context.become(beh(context), discardOld = false); sender ! "ok" }
+          case Become(beh) ⇒ { context.become(beh(context), discardOld = false); sender() ! "ok" }
-          case x           ⇒ sender ! 42
+          case x           ⇒ sender() ! 42
         }
       }))
       a ! "hello"
       expectMsg(42)
       a ! Become(ctx ⇒ {
         case "fail" ⇒ throw new RuntimeException("buh")
-        case x      ⇒ ctx.sender ! 43
+        case x      ⇒ ctx.sender() ! 43
       })
       expectMsg("ok")
       a ! "hello"

akka-actor-tests/src/test/scala/akka/actor/ActorLookupSpec.scala

@@ -24,11 +24,11 @@ object ActorLookupSpec {
 
   class Node extends Actor {
     def receive = {
-      case Create(name)       ⇒ sender ! context.actorOf(p, name)
+      case Create(name)       ⇒ sender() ! context.actorOf(p, name)
-      case LookupElems(path)  ⇒ sender ! context.actorFor(path)
+      case LookupElems(path)  ⇒ sender() ! context.actorFor(path)
-      case LookupString(path) ⇒ sender ! context.actorFor(path)
+      case LookupString(path) ⇒ sender() ! context.actorFor(path)
-      case LookupPath(path)   ⇒ sender ! context.actorFor(path)
+      case LookupPath(path)   ⇒ sender() ! context.actorFor(path)
-      case GetSender(ref)     ⇒ ref ! sender
+      case GetSender(ref)     ⇒ ref ! sender()
     }
   }
 

akka-actor-tests/src/test/scala/akka/actor/ActorMailboxSpec.scala

@@ -149,7 +149,7 @@ object ActorMailboxSpec {
 
   class QueueReportingActor extends Actor {
     def receive = {
-      case _ ⇒ sender ! context.asInstanceOf[ActorCell].mailbox.messageQueue
+      case _ ⇒ sender() ! context.asInstanceOf[ActorCell].mailbox.messageQueue
     }
   }
 

akka-actor-tests/src/test/scala/akka/actor/ActorPerfSpec.scala

@@ -22,13 +22,13 @@ object ActorPerfSpec {
 
   class EmptyActor extends Actor {
     def receive = {
-      case IsAlive ⇒ sender ! Alive
+      case IsAlive ⇒ sender() ! Alive
     }
   }
 
   class EmptyArgsActor(val foo: Int, val bar: Int) extends Actor {
     def receive = {
-      case IsAlive ⇒ sender ! Alive
+      case IsAlive ⇒ sender() ! Alive
     }
   }
 
@@ -36,15 +36,15 @@ object ActorPerfSpec {
 
     def receive = {
       case IsAlive ⇒
-        sender ! Alive
+        sender() ! Alive
       case Create(number, propsCreator) ⇒
         for (i ← 1 to number) {
           context.actorOf(propsCreator.apply())
         }
-        sender ! Created
+        sender() ! Created
       case WaitForChildren(number) ⇒
         context.children.foreach(_ ! IsAlive)
-        context.become(waiting(number, sender), false)
+        context.become(waiting(number, sender()), false)
     }
 
     def waiting(number: Int, replyTo: ActorRef): Receive = {

akka-actor-tests/src/test/scala/akka/actor/ActorRefSpec.scala

@@ -25,15 +25,15 @@ object ActorRefSpec {
 
     def receive = {
       case "complexRequest" ⇒ {
-        replyTo = sender
+        replyTo = sender()
         val worker = context.actorOf(Props[WorkerActor])
         worker ! "work"
       }
       case "complexRequest2" ⇒
         val worker = context.actorOf(Props[WorkerActor])
-        worker ! ReplyTo(sender)
+        worker ! ReplyTo(sender())
       case "workDone"      ⇒ replyTo ! "complexReply"
-      case "simpleRequest" ⇒ sender ! "simpleReply"
+      case "simpleRequest" ⇒ sender() ! "simpleReply"
     }
   }
 
@@ -42,7 +42,7 @@ object ActorRefSpec {
     def receive = {
       case "work" ⇒ {
         work()
-        sender ! "workDone"
+        sender() ! "workDone"
         context.stop(self)
       }
       case ReplyTo(replyTo) ⇒ {
@@ -71,7 +71,7 @@ object ActorRefSpec {
 
   class OuterActor(val inner: ActorRef) extends Actor {
     def receive = {
-      case "self" ⇒ sender ! self
+      case "self" ⇒ sender() ! self
       case x      ⇒ inner forward x
     }
   }
@@ -80,7 +80,7 @@ object ActorRefSpec {
     val fail = new InnerActor
 
     def receive = {
-      case "self" ⇒ sender ! self
+      case "self" ⇒ sender() ! self
       case x      ⇒ inner forward x
     }
   }
@@ -91,8 +91,8 @@ object ActorRefSpec {
 
   class InnerActor extends Actor {
     def receive = {
-      case "innerself" ⇒ sender ! self
+      case "innerself" ⇒ sender() ! self
-      case other       ⇒ sender ! other
+      case other       ⇒ sender() ! other
     }
   }
 
@@ -100,8 +100,8 @@ object ActorRefSpec {
     val fail = new InnerActor
 
     def receive = {
-      case "innerself" ⇒ sender ! self
+      case "innerself" ⇒ sender() ! self
-      case other       ⇒ sender ! other
+      case other       ⇒ sender() ! other
     }
   }
 
@@ -335,7 +335,7 @@ class ActorRefSpec extends AkkaSpec with DefaultTimeout {
     "support nested actorOfs" in {
       val a = system.actorOf(Props(new Actor {
         val nested = system.actorOf(Props(new Actor { def receive = { case _ ⇒ } }))
-        def receive = { case _ ⇒ sender ! nested }
+        def receive = { case _ ⇒ sender() ! nested }
       }))
 
       val nested = Await.result((a ? "any").mapTo[ActorRef], timeout.duration)
@@ -391,8 +391,8 @@ class ActorRefSpec extends AkkaSpec with DefaultTimeout {
       val timeout = Timeout(20000)
       val ref = system.actorOf(Props(new Actor {
         def receive = {
-          case 5 ⇒ sender ! "five"
+          case 5 ⇒ sender() ! "five"
-          case 0 ⇒ sender ! "null"
+          case 0 ⇒ sender() ! "null"
         }
       }))
 
@@ -438,7 +438,7 @@ class ActorRefSpec extends AkkaSpec with DefaultTimeout {
             def receive = { case _ ⇒ }
           }), "child")
 
-        def receive = { case name: String ⇒ sender ! context.child(name).isDefined }
+        def receive = { case name: String ⇒ sender() ! context.child(name).isDefined }
       }), "parent")
 
       assert(Await.result((parent ? "child"), remaining) === true)

akka-actor-tests/src/test/scala/akka/actor/ActorSelectionSpec.scala

@@ -24,12 +24,12 @@ object ActorSelectionSpec {
 
   class Node extends Actor {
     def receive = {
-      case Create(name)       ⇒ sender ! context.actorOf(p, name)
+      case Create(name)       ⇒ sender() ! context.actorOf(p, name)
-      case SelectString(path) ⇒ sender ! context.actorSelection(path)
+      case SelectString(path) ⇒ sender() ! context.actorSelection(path)
-      case SelectPath(path)   ⇒ sender ! context.actorSelection(path)
+      case SelectPath(path)   ⇒ sender() ! context.actorSelection(path)
-      case GetSender(ref)     ⇒ ref ! sender
+      case GetSender(ref)     ⇒ ref ! sender()
       case Forward(path, msg) ⇒ context.actorSelection(path).forward(msg)
-      case msg                ⇒ sender ! msg
+      case msg                ⇒ sender() ! msg
     }
   }
 

akka-actor-tests/src/test/scala/akka/actor/ActorSystemSpec.scala

@@ -37,7 +37,7 @@ object ActorSystemSpec {
 
     def receive = {
       case n: Int ⇒
-        master = sender
+        master = sender()
         terminaters = Set() ++ (for (i ← 1 to n) yield {
           val man = context.watch(context.system.actorOf(Props[Terminater]))
           man ! "run"

akka-actor-tests/src/test/scala/akka/actor/ActorWithBoundedStashSpec.scala

@@ -23,7 +23,7 @@ object ActorWithBoundedStashSpec {
     def receive = {
       case msg: String if msg.startsWith("hello") ⇒
         stash()
-        sender ! "ok"
+        sender() ! "ok"
 
       case "world" ⇒
         context.become(afterWorldBehaviour)
@@ -42,13 +42,13 @@ object ActorWithBoundedStashSpec {
     def receive = {
       case msg: String if msg.startsWith("hello") ⇒
         numStashed += 1
-        try { stash(); sender ! "ok" } catch {
+        try { stash(); sender() ! "ok" } catch {
           case _: StashOverflowException ⇒
             if (numStashed == 21) {
-              sender ! "STASHOVERFLOW"
+              sender() ! "STASHOVERFLOW"
               context stop self
             } else {
-              sender ! "Unexpected StashOverflowException: " + numStashed
+              sender() ! "Unexpected StashOverflowException: " + numStashed
             }
         }
     }

akka-actor-tests/src/test/scala/akka/actor/Bench.scala

@@ -42,7 +42,7 @@ object Chameneos {
 
       case Exit ⇒
         colour = FADED
-        sender ! MeetingCount(meetings)
+        sender() ! MeetingCount(meetings)
     }
 
     def complement(otherColour: Colour): Colour = colour match {
@@ -95,11 +95,11 @@ object Chameneos {
               n -= 1
               chameneo ! msg
               waitingChameneo = None
-            case None ⇒ waitingChameneo = Some(sender)
+            case None ⇒ waitingChameneo = Some(sender())
           }
         } else {
           waitingChameneo.foreach(_ ! Exit)
-          sender ! Exit
+          sender() ! Exit
         }
     }
   }

akka-actor-tests/src/test/scala/akka/actor/ConsistencySpec.scala

@@ -32,18 +32,18 @@ object ConsistencySpec {
       case step: Long ⇒
 
         if (lastStep != (step - 1))
-          sender ! "Test failed: Last step %s, this step %s".format(lastStep, step)
+          sender() ! "Test failed: Last step %s, this step %s".format(lastStep, step)
 
         var shouldBeFortyTwo = left.value + right.value
         if (shouldBeFortyTwo != 42)
-          sender ! "Test failed: 42 failed"
+          sender() ! "Test failed: 42 failed"
         else {
           left.value += 1
           right.value -= 1
         }
 
         lastStep = step
-      case "done" ⇒ sender ! "done"; context.stop(self)
+      case "done" ⇒ sender() ! "done"; context.stop(self)
     }
   }
 }

akka-actor-tests/src/test/scala/akka/actor/DeathWatchSpec.scala

@@ -90,7 +90,7 @@ trait DeathWatchSpec { this: AkkaSpec with ImplicitSender with DefaultTimeout
         context.watch(terminal)
         context.unwatch(terminal)
         def receive = {
-          case "ping"        ⇒ sender ! "pong"
+          case "ping"        ⇒ sender() ! "pong"
           case t: Terminated ⇒ testActor ! WrappedTerminated(t)
         }
       }).withDeploy(Deploy.local))
@@ -113,7 +113,7 @@ trait DeathWatchSpec { this: AkkaSpec with ImplicitSender with DefaultTimeout
       filterException[ActorKilledException] {
         val supervisor = system.actorOf(Props(new Supervisor(
           OneForOneStrategy(maxNrOfRetries = 2)(List(classOf[Exception])))))
-        val terminalProps = Props(new Actor { def receive = { case x ⇒ sender ! x } })
+        val terminalProps = Props(new Actor { def receive = { case x ⇒ sender() ! x } })
         val terminal = Await.result((supervisor ? terminalProps).mapTo[ActorRef], timeout.duration)
 
         val monitor = startWatching(terminal)

akka-actor-tests/src/test/scala/akka/actor/FSMTimingSpec.scala

@@ -216,7 +216,7 @@ object FSMTimingSpec {
         setTimer("hallo", Tock, 1.milli.dilated)
         TestKit.awaitCond(context.asInstanceOf[ActorCell].mailbox.hasMessages, 1.second.dilated)
         cancelTimer("hallo")
-        sender ! Tick
+        sender() ! Tick
         setTimer("hallo", Tock, 500.millis.dilated)
         stay
       case Event(Tock, _) ⇒

akka-actor-tests/src/test/scala/akka/actor/FSMTransitionSpec.scala

@@ -97,7 +97,7 @@ class FSMTransitionSpec extends AkkaSpec with ImplicitSender {
       val fsmref = system.actorOf(Props(new Actor with FSM[Int, ActorRef] {
         startWith(0, null)
         when(0) {
-          case Event("switch", _) ⇒ goto(1) using sender
+          case Event("switch", _) ⇒ goto(1) using sender()
         }
         onTransition {
           case x -> y ⇒ nextStateData ! (x -> y)
@@ -105,9 +105,9 @@ class FSMTransitionSpec extends AkkaSpec with ImplicitSender {
         when(1) {
           case Event("test", _) ⇒
             try {
-              sender ! s"failed: ${nextStateData}"
+              sender() ! s"failed: ${nextStateData}"
             } catch {
-              case _: IllegalStateException ⇒ sender ! "ok"
+              case _: IllegalStateException ⇒ sender() ! "ok"
             }
             stay
         }

akka-actor-tests/src/test/scala/akka/actor/ForwardActorSpec.scala

@@ -17,7 +17,7 @@ object ForwardActorSpec {
 
   def createForwardingChain(system: ActorSystem): ActorRef = {
     val replier = system.actorOf(Props(new Actor {
-      def receive = { case x ⇒ sender ! x }
+      def receive = { case x ⇒ sender() ! x }
     }))
 
     def mkforwarder(forwardTo: ActorRef) = system.actorOf(Props(

akka-actor-tests/src/test/scala/akka/actor/HotSwapSpec.scala

@@ -19,8 +19,8 @@ class HotSwapSpec extends AkkaSpec with ImplicitSender {
   "An Actor" must {
     "be able to become in its constructor" in {
       val a = system.actorOf(Props(new Becomer {
-        context.become { case always ⇒ sender ! always }
+        context.become { case always ⇒ sender() ! always }
-        def receive = { case always ⇒ sender ! "FAILURE" }
+        def receive = { case always ⇒ sender() ! "FAILURE" }
       }))
       a ! "pigdog"
       expectMsg("pigdog")
@@ -28,8 +28,8 @@ class HotSwapSpec extends AkkaSpec with ImplicitSender {
 
     "be able to become multiple times in its constructor" in {
       val a = system.actorOf(Props(new Becomer {
-        for (i ← 1 to 4) context.become({ case always ⇒ sender ! i + ":" + always })
+        for (i ← 1 to 4) context.become({ case always ⇒ sender() ! i + ":" + always })
-        def receive = { case always ⇒ sender ! "FAILURE" }
+        def receive = { case always ⇒ sender() ! "FAILURE" }
       }))
       a ! "pigdog"
       expectMsg("4:pigdog")
@@ -37,8 +37,8 @@ class HotSwapSpec extends AkkaSpec with ImplicitSender {
 
     "be able to become with stacking in its constructor" in {
       val a = system.actorOf(Props(new Becomer {
-        context.become({ case always ⇒ sender ! "pigdog:" + always; context.unbecome() }, false)
+        context.become({ case always ⇒ sender() ! "pigdog:" + always; context.unbecome() }, false)
-        def receive = { case always ⇒ sender ! "badass:" + always }
+        def receive = { case always ⇒ sender() ! "badass:" + always }
       }))
       a ! "pigdog"
       expectMsg("pigdog:pigdog")
@@ -48,8 +48,8 @@ class HotSwapSpec extends AkkaSpec with ImplicitSender {
 
     "be able to become, with stacking, multiple times in its constructor" in {
       val a = system.actorOf(Props(new Becomer {
-        for (i ← 1 to 4) context.become({ case always ⇒ sender ! i + ":" + always; context.unbecome() }, false)
+        for (i ← 1 to 4) context.become({ case always ⇒ sender() ! i + ":" + always; context.unbecome() }, false)
-        def receive = { case always ⇒ sender ! "FAILURE" }
+        def receive = { case always ⇒ sender() ! "FAILURE" }
       }))
       a ! "pigdog"
       a ! "pigdog"
@@ -64,8 +64,8 @@ class HotSwapSpec extends AkkaSpec with ImplicitSender {
     "be able to hotswap its behavior with become(..)" in {
       val a = system.actorOf(Props(new Actor {
         def receive = {
-          case "init" ⇒ sender ! "init"
+          case "init" ⇒ sender() ! "init"
-          case "swap" ⇒ context.become({ case x: String ⇒ context.sender ! x })
+          case "swap" ⇒ context.become({ case x: String ⇒ context.sender() ! x })
         }
       }))
 
@@ -79,9 +79,9 @@ class HotSwapSpec extends AkkaSpec with ImplicitSender {
     "be able to revert hotswap its behavior with unbecome" in {
       val a = system.actorOf(Props(new Actor {
         def receive = {
-          case "init" ⇒ sender ! "init"
+          case "init" ⇒ sender() ! "init"
           case "swap" ⇒ context.become({
-            case "swapped" ⇒ sender ! "swapped"
+            case "swapped" ⇒ sender() ! "swapped"
             case "revert"  ⇒ context.unbecome()
           })
         }
@@ -103,14 +103,14 @@ class HotSwapSpec extends AkkaSpec with ImplicitSender {
 
       val a = system.actorOf(Props(new Actor {
         def receive = {
-          case "state" ⇒ sender ! "0"
+          case "state" ⇒ sender() ! "0"
           case "swap" ⇒
             context.become({
-              case "state"   ⇒ sender ! "1"
+              case "state"   ⇒ sender() ! "1"
-              case "swapped" ⇒ sender ! "swapped"
+              case "swapped" ⇒ sender() ! "swapped"
               case "crash"   ⇒ throw new Exception("Crash (expected)!")
             })
-            sender ! "swapped"
+            sender() ! "swapped"
         }
       }))
       a ! "state"

akka-actor-tests/src/test/scala/akka/actor/LocalActorRefProviderSpec.scala

@@ -45,8 +45,8 @@ class LocalActorRefProviderSpec extends AkkaSpec(LocalActorRefProviderSpec.confi
         val child = context.actorOf(Props.empty, name = childName)
         def receive = {
           case "lookup" ⇒
-            if (childName == child.path.name) sender ! context.actorFor(childName)
+            if (childName == child.path.name) sender() ! context.actorFor(childName)
-            else sender ! s"$childName is not ${child.path.name}!"
+            else sender() ! s"$childName is not ${child.path.name}!"
         }
       }))
       a.tell("lookup", testActor)
@@ -62,7 +62,7 @@ class LocalActorRefProviderSpec extends AkkaSpec(LocalActorRefProviderSpec.confi
       val GetChild = "GetChild"
       val a = watch(system.actorOf(Props(new Actor {
         val child = context.actorOf(Props.empty)
-        def receive = { case `GetChild` ⇒ sender ! child }
+        def receive = { case `GetChild` ⇒ sender() ! child }
       })))
       a.tell(GetChild, testActor)
       val child = expectMsgType[ActorRef]

akka-actor-tests/src/test/scala/akka/actor/RestartStrategySpec.scala

@@ -215,7 +215,7 @@ class RestartStrategySpec extends AkkaSpec("akka.actor.serialize-messages = off"
       val boss = system.actorOf(Props(new Actor {
         override val supervisorStrategy = OneForOneStrategy(withinTimeRange = 1 second)(List(classOf[Throwable]))
         def receive = {
-          case p: Props      ⇒ sender ! context.watch(context.actorOf(p))
+          case p: Props      ⇒ sender() ! context.watch(context.actorOf(p))
           case t: Terminated ⇒ maxNoOfRestartsLatch.open()
         }
       }))

akka-actor-tests/src/test/scala/akka/actor/SchedulerSpec.scala

@@ -42,7 +42,7 @@ trait SchedulerSpec extends BeforeAndAfterEach with DefaultTimeout with Implicit
         def receive = {
           case Tick ⇒
             if (ticks < 3) {
-              sender ! Tock
+              sender() ! Tock
               ticks += 1
             }
         }
@@ -66,7 +66,7 @@ trait SchedulerSpec extends BeforeAndAfterEach with DefaultTimeout with Implicit
     }
 
     "stop continuous scheduling if the receiving actor has been terminated" taggedAs TimingTest in {
-      val actor = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender ! x } }))
+      val actor = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender() ! x } }))
 
       // run immediately and then every 100 milliseconds
       collectCancellable(system.scheduler.schedule(0 milliseconds, 100 milliseconds, actor, "msg"))

akka-actor-tests/src/test/scala/akka/actor/Supervisor.scala

@@ -10,7 +10,7 @@ package akka.actor
 class Supervisor(override val supervisorStrategy: SupervisorStrategy) extends Actor {
 
   def receive = {
-    case x: Props ⇒ sender ! context.actorOf(x)
+    case x: Props ⇒ sender() ! context.actorOf(x)
   }
   // need to override the default of stopping all children upon restart, tests rely on keeping them around
   override def preRestart(cause: Throwable, msg: Option[Any]) {}

akka-actor-tests/src/test/scala/akka/actor/SupervisorHierarchySpec.scala

@@ -36,7 +36,7 @@ object SupervisorHierarchySpec {
   class CountDownActor(countDown: CountDownLatch, override val supervisorStrategy: SupervisorStrategy) extends Actor {
 
     def receive = {
-      case p: Props ⇒ sender ! context.actorOf(p)
+      case p: Props ⇒ sender() ! context.actorOf(p)
     }
     // test relies on keeping children around during restart
     override def preRestart(cause: Throwable, msg: Option[Any]) {}
@@ -48,9 +48,9 @@ object SupervisorHierarchySpec {
   class Resumer extends Actor {
     override def supervisorStrategy = OneForOneStrategy() { case _ ⇒ SupervisorStrategy.Resume }
     def receive = {
-      case "spawn" ⇒ sender ! context.actorOf(Props[Resumer])
+      case "spawn" ⇒ sender() ! context.actorOf(Props[Resumer])
       case "fail"  ⇒ throw new Exception("expected")
-      case "ping"  ⇒ sender ! "pong"
+      case "ping"  ⇒ sender() ! "pong"
     }
   }
 
@@ -197,23 +197,23 @@ object SupervisorHierarchySpec {
     }
     override val supervisorStrategy = OneForOneStrategy()(unwrap andThen {
       case (_: Failure, _) if pongsToGo > 0 ⇒
-        log :+= Event("pongOfDeath resuming " + sender, identityHashCode(this))
+        log :+= Event("pongOfDeath resuming " + sender(), identityHashCode(this))
         Resume
       case (f: Failure, orig) ⇒
         if (f.depth > 0) {
           setFlags(f.directive)
-          log :+= Event("escalating " + f + " from " + sender, identityHashCode(this))
+          log :+= Event("escalating " + f + " from " + sender(), identityHashCode(this))
           throw f.copy(depth = f.depth - 1)
         }
         val prefix = orig match {
           case f: Failure ⇒ "applying "
           case _          ⇒ "re-applying "
         }
-        log :+= Event(prefix + f + " to " + sender, identityHashCode(this))
+        log :+= Event(prefix + f + " to " + sender(), identityHashCode(this))
         if (myLevel > 3 && f.failPost == 0 && f.stop) Stop else f.directive
       case (_, x) ⇒
-        log :+= Event("unhandled exception from " + sender + Logging.stackTraceFor(x), identityHashCode(this))
+        log :+= Event("unhandled exception from " + sender() + Logging.stackTraceFor(x), identityHashCode(this))
-        sender ! Dump(0)
+        sender() ! Dump(0)
         context.system.scheduler.scheduleOnce(1 second, self, Dump(0))(context.dispatcher)
         Resume
     })
@@ -276,7 +276,7 @@ object SupervisorHierarchySpec {
           setFlags(f.directive)
           stateCache.put(self.path, stateCache.get(self.path).copy(failConstr = f.copy()))
           throw f
-        case "ping"      ⇒ { Thread.sleep((random.nextFloat * 1.03).toLong); sender ! "pong" }
+        case "ping"      ⇒ { Thread.sleep((random.nextFloat * 1.03).toLong); sender() ! "pong" }
         case Dump(0)     ⇒ abort("dump")
         case Dump(level) ⇒ context.children foreach (_ ! Dump(level - 1))
         case Terminated(ref) ⇒
@@ -296,7 +296,7 @@ object SupervisorHierarchySpec {
           } else {
             // WARNING: The Terminated that is logged by this is logged by check() above, too. It is not
             // an indication of duplicate Terminate messages
-            log :+= Event(sender + " terminated while pongOfDeath", identityHashCode(Hierarchy.this))
+            log :+= Event(sender() + " terminated while pongOfDeath", identityHashCode(Hierarchy.this))
           }
         case Abort ⇒ abort("terminating")
         case PingOfDeath ⇒
@@ -518,8 +518,8 @@ object SupervisorHierarchySpec {
         bury(path)
         stay
       case Event("pong", _) ⇒
-        pingChildren -= sender
+        pingChildren -= sender()
-        idleChildren :+= sender
+        idleChildren :+= sender()
         stay
       case Event(StateTimeout, todo) ⇒
         log.info("dumping state due to StateTimeout")
@@ -538,8 +538,8 @@ object SupervisorHierarchySpec {
 
     when(Finishing) {
       case Event("pong", _) ⇒
-        pingChildren -= sender
+        pingChildren -= sender()
-        idleChildren :+= sender
+        idleChildren :+= sender()
         if (pingChildren.isEmpty) goto(LastPing) else stay
       case Event(Died(ref), _) ⇒
         bury(ref)
@@ -555,8 +555,8 @@ object SupervisorHierarchySpec {
 
     when(LastPing) {
       case Event("pong", _) ⇒
-        pingChildren -= sender
+        pingChildren -= sender()
-        idleChildren :+= sender
+        idleChildren :+= sender()
         if (pingChildren.isEmpty) goto(Stopping) else stay
       case Event(Died(ref), _) ⇒
         bury(ref)
@@ -605,7 +605,7 @@ object SupervisorHierarchySpec {
         testActor ! "timeout in Stopping"
         stop
       case Event(e: ErrorLog, _) ⇒
-        errors :+= sender -> e
+        errors :+= sender() -> e
         goto(Failed)
     }
 
@@ -631,7 +631,7 @@ object SupervisorHierarchySpec {
     when(Failed, stateTimeout = 5.seconds.dilated) {
       case Event(e: ErrorLog, _) ⇒
         if (!e.msg.startsWith("not resumed") || !ignoreNotResumedLogs)
-          errors :+= sender -> e
+          errors :+= sender() -> e
         stay
       case Event(Terminated(r), _) if r == hierarchy ⇒
         printErrors()
@@ -694,7 +694,7 @@ object SupervisorHierarchySpec {
       case Event(e: ErrorLog, _) ⇒
         if (e.msg.startsWith("not resumed")) stay
         else {
-          errors :+= sender -> e
+          errors :+= sender() -> e
           // don’t stop the hierarchy, that is going to happen all by itself and in the right order
           goto(Failed)
         }
@@ -794,7 +794,7 @@ class SupervisorHierarchySpec extends AkkaSpec(SupervisorHierarchySpec.config) w
       val slowResumer = system.actorOf(Props(new Actor {
         override def supervisorStrategy = OneForOneStrategy() { case _ ⇒ Await.ready(latch, 4.seconds.dilated); SupervisorStrategy.Resume }
         def receive = {
-          case "spawn" ⇒ sender ! context.actorOf(Props[Resumer])
+          case "spawn" ⇒ sender() ! context.actorOf(Props[Resumer])
         }
       }), "slowResumer")
       slowResumer ! "spawn"
@@ -848,7 +848,7 @@ class SupervisorHierarchySpec extends AkkaSpec(SupervisorHierarchySpec.config) w
                 postRestartCalled.incrementAndGet()
               }
               override def receive = {
-                case m ⇒ sender ! m
+                case m ⇒ sender() ! m
               }
             }), "failChild")
 

akka-actor-tests/src/test/scala/akka/actor/SupervisorMiscSpec.scala

@@ -42,7 +42,7 @@ class SupervisorMiscSpec extends AkkaSpec(SupervisorMiscSpec.config) with Defaul
         val workerProps = Props(new Actor {
           override def postRestart(cause: Throwable) { countDownLatch.countDown() }
           def receive = {
-            case "status" ⇒ this.sender ! "OK"
+            case "status" ⇒ this.sender() ! "OK"
             case _        ⇒ this.context.stop(self)
           }
         })
@@ -146,7 +146,7 @@ class SupervisorMiscSpec extends AkkaSpec(SupervisorMiscSpec.config) with Defaul
     "have access to the failing child’s reference in supervisorStrategy" in {
       val parent = system.actorOf(Props(new Actor {
         override val supervisorStrategy = OneForOneStrategy() {
-          case _: Exception ⇒ testActor ! sender; SupervisorStrategy.Stop
+          case _: Exception ⇒ testActor ! sender(); SupervisorStrategy.Stop
         }
         def receive = {
           case "doit" ⇒ context.actorOf(Props.empty, "child") ! Kill

akka-actor-tests/src/test/scala/akka/actor/SupervisorSpec.scala

@@ -36,13 +36,13 @@ object SupervisorSpec {
     def receive = {
       case Ping ⇒
         sendTo ! PingMessage
-        if (sender != sendTo)
+        if (sender() != sendTo)
-          sender ! PongMessage
+          sender() ! PongMessage
       case Die ⇒
         throw new RuntimeException(ExceptionMessage)
       case DieReply ⇒
         val e = new RuntimeException(ExceptionMessage)
-        sender ! Status.Failure(e)
+        sender() ! Status.Failure(e)
         throw e
     }
 
@@ -172,7 +172,7 @@ class SupervisorSpec extends AkkaSpec("akka.actor.serialize-messages = off") wit
         override def postStop() { postStops += 1; testActor ! ("postStop" + postStops) }
         def receive = {
           case "crash" ⇒ { testActor ! "crashed"; throw new RuntimeException("Expected") }
-          case "ping"  ⇒ sender ! "pong"
+          case "ping"  ⇒ sender() ! "pong"
         }
       }
       val master = system.actorOf(Props(new Actor {
@@ -349,10 +349,10 @@ class SupervisorSpec extends AkkaSpec("akka.actor.serialize-messages = off") wit
         }
 
         def receive = {
-          case Ping ⇒ sender ! PongMessage
+          case Ping ⇒ sender() ! PongMessage
           case DieReply ⇒
             val e = new RuntimeException("Expected")
-            sender ! Status.Failure(e)
+            sender() ! Status.Failure(e)
             throw e
         }
       })
@@ -386,7 +386,7 @@ class SupervisorSpec extends AkkaSpec("akka.actor.serialize-messages = off") wit
           override def postRestart(reason: Throwable): Unit = testActor ! "child restarted"
           def receive = {
             case l: TestLatch ⇒ { Await.ready(l, 5 seconds); throw new IllegalStateException("OHNOES") }
-            case "test"       ⇒ sender ! "child green"
+            case "test"       ⇒ sender() ! "child green"
           }
         }), "child"))
 
@@ -401,9 +401,9 @@ class SupervisorSpec extends AkkaSpec("akka.actor.serialize-messages = off") wit
         def receive = {
           case Terminated(a) if a.path == child.path ⇒ testActor ! "child terminated"
           case l: TestLatch                          ⇒ child ! l
-          case "test"                                ⇒ sender ! "green"
+          case "test"                                ⇒ sender() ! "green"
           case "testchild"                           ⇒ child forward "test"
-          case "testchildAndAck"                     ⇒ child forward "test"; sender ! "ack"
+          case "testchildAndAck"                     ⇒ child forward "test"; sender() ! "ack"
         }
       }))
 

akka-actor-tests/src/test/scala/akka/actor/SupervisorTreeSpec.scala

@@ -25,7 +25,7 @@ class SupervisorTreeSpec extends AkkaSpec("akka.actor.serialize-messages = off")
           val p = Props(new Actor {
             override val supervisorStrategy = OneForOneStrategy(maxNrOfRetries = 3, withinTimeRange = 1 second)(List(classOf[Exception]))
             def receive = {
-              case p: Props ⇒ sender ! context.actorOf(p)
+              case p: Props ⇒ sender() ! context.actorOf(p)
             }
             override def preRestart(cause: Throwable, msg: Option[Any]) { testActor ! self.path }
           })

akka-actor-tests/src/test/scala/akka/actor/Ticket669Spec.scala

@@ -59,11 +59,11 @@ object Ticket669Spec {
     }
 
     override def preRestart(reason: scala.Throwable, msg: Option[Any]) {
-      sender ! "failure1"
+      sender() ! "failure1"
     }
 
     override def postStop() {
-      sender ! "failure2"
+      sender() ! "failure2"
     }
   }
 }

akka-actor-tests/src/test/scala/akka/actor/TypedActorSpec.scala

@@ -353,7 +353,7 @@ class TypedActorSpec extends AkkaSpec(TypedActorSpec.config)
             case e: IllegalStateException if e.getMessage == "expected" ⇒ SupervisorStrategy.Resume
           }
           def receive = {
-            case p: TypedProps[_] ⇒ context.sender ! TypedActor(context).typedActorOf(p)
+            case p: TypedProps[_] ⇒ context.sender() ! TypedActor(context).typedActorOf(p)
           }
         }))
         val t = Await.result((boss ? TypedProps[Bar](classOf[Foo], classOf[Bar]).withTimeout(2 seconds)).mapTo[Foo], timeout.duration)

akka-actor-tests/src/test/scala/akka/actor/dispatch/ActorModelSpec.scala

@@ -86,15 +86,15 @@ object ActorModelSpec {
       case Meet(sign, wait)             ⇒ { ack(); sign.countDown(); wait.await(); busy.switchOff(()) }
       case Wait(time)                   ⇒ { ack(); Thread.sleep(time); busy.switchOff(()) }
       case WaitAck(time, l)             ⇒ { ack(); Thread.sleep(time); l.countDown(); busy.switchOff(()) }
-      case Reply(msg)                   ⇒ { ack(); sender ! msg; busy.switchOff(()) }
+      case Reply(msg)                   ⇒ { ack(); sender() ! msg; busy.switchOff(()) }
-      case TryReply(msg)                ⇒ { ack(); sender.tell(msg, null); busy.switchOff(()) }
+      case TryReply(msg)                ⇒ { ack(); sender().tell(msg, null); busy.switchOff(()) }
       case Forward(to, msg)             ⇒ { ack(); to.forward(msg); busy.switchOff(()) }
       case CountDown(latch)             ⇒ { ack(); latch.countDown(); busy.switchOff(()) }
       case Increment(count)             ⇒ { ack(); count.incrementAndGet(); busy.switchOff(()) }
       case CountDownNStop(l)            ⇒ { ack(); l.countDown(); context.stop(self); busy.switchOff(()) }
       case Restart                      ⇒ { ack(); busy.switchOff(()); throw new Exception("Restart requested") }
-      case Interrupt                    ⇒ { ack(); sender ! Status.Failure(new ActorInterruptedException(new InterruptedException("Ping!"))); busy.switchOff(()); throw new InterruptedException("Ping!") }
+      case Interrupt                    ⇒ { ack(); sender() ! Status.Failure(new ActorInterruptedException(new InterruptedException("Ping!"))); busy.switchOff(()); throw new InterruptedException("Ping!") }
-      case InterruptNicely(msg)         ⇒ { ack(); sender ! msg; busy.switchOff(()); Thread.currentThread().interrupt() }
+      case InterruptNicely(msg)         ⇒ { ack(); sender() ! msg; busy.switchOff(()); Thread.currentThread().interrupt() }
       case ThrowException(e: Throwable) ⇒ { ack(); busy.switchOff(()); throw e }
       case DoubleStop                   ⇒ { ack(); context.stop(self); context.stop(self); busy.switchOff }
     }

akka-actor-tests/src/test/scala/akka/actor/dispatch/DispatcherActorSpec.scala

@@ -37,7 +37,7 @@ object DispatcherActorSpec {
     """
   class TestActor extends Actor {
     def receive = {
-      case "Hello"   ⇒ sender ! "World"
+      case "Hello"   ⇒ sender() ! "World"
       case "Failure" ⇒ throw new RuntimeException("Expected exception; to test fault-tolerance")
     }
   }
@@ -86,7 +86,7 @@ class DispatcherActorSpec extends AkkaSpec(DispatcherActorSpec.config) with Defa
       val slowOne = system.actorOf(
         Props(new Actor {
           def receive = {
-            case "hogexecutor" ⇒ { sender ! "OK"; start.await }
+            case "hogexecutor" ⇒ { sender() ! "OK"; start.await }
             case "ping"        ⇒ if (works.get) latch.countDown()
           }
         }).withDispatcher(throughputDispatcher))

akka-actor-tests/src/test/scala/akka/actor/dispatch/DispatchersSpec.scala

@@ -51,7 +51,7 @@ object DispatchersSpec {
 
   class ThreadNameEcho extends Actor {
     def receive = {
-      case _ ⇒ sender ! Thread.currentThread.getName
+      case _ ⇒ sender() ! Thread.currentThread.getName
     }
   }
 }

akka-actor-tests/src/test/scala/akka/actor/dispatch/PinnedActorSpec.scala

@@ -20,7 +20,7 @@ object PinnedActorSpec {
 
   class TestActor extends Actor {
     def receive = {
-      case "Hello"   ⇒ sender ! "World"
+      case "Hello"   ⇒ sender() ! "World"
       case "Failure" ⇒ throw new RuntimeException("Expected exception; to test fault-tolerance")
     }
   }

akka-actor-tests/src/test/scala/akka/dataflow/Future2Actor.scala

@@ -39,8 +39,8 @@ class Future2ActorSpec extends AkkaSpec with DefaultTimeout {
     "support reply via sender" in {
       val actor = system.actorOf(Props(new Actor {
         def receive = {
-          case "do" ⇒ Future(31) pipeTo context.sender
+          case "do" ⇒ Future(31) pipeTo context.sender()
-          case "ex" ⇒ Future(throw new AssertionError) pipeTo context.sender
+          case "ex" ⇒ Future(throw new AssertionError) pipeTo context.sender()
         }
       }))
       Await.result(actor ? "do", timeout.duration) should be(31)

akka-actor-tests/src/test/scala/akka/dispatch/FutureSpec.scala

@@ -31,9 +31,9 @@ object FutureSpec {
 
   class TestActor extends Actor {
     def receive = {
-      case "Hello" ⇒ sender ! "World"
+      case "Hello" ⇒ sender() ! "World"
       case "Failure" ⇒
-        sender ! Status.Failure(new RuntimeException("Expected exception; to test fault-tolerance"))
+        sender() ! Status.Failure(new RuntimeException("Expected exception; to test fault-tolerance"))
       case "NoReply" ⇒
     }
   }
@@ -41,11 +41,11 @@ object FutureSpec {
   class TestDelayActor(await: TestLatch) extends Actor {
     def receive = {
       case "Hello" ⇒
-        FutureSpec.ready(await, TestLatch.DefaultTimeout); sender ! "World"
+        FutureSpec.ready(await, TestLatch.DefaultTimeout); sender() ! "World"
       case "NoReply" ⇒ FutureSpec.ready(await, TestLatch.DefaultTimeout)
       case "Failure" ⇒
         FutureSpec.ready(await, TestLatch.DefaultTimeout)
-        sender ! Status.Failure(new RuntimeException("Expected exception; to test fault-tolerance"))
+        sender() ! Status.Failure(new RuntimeException("Expected exception; to test fault-tolerance"))
     }
   }
 
@@ -200,7 +200,7 @@ class FutureSpec extends AkkaSpec with Checkers with BeforeAndAfterAll with Defa
       "will return a result" must {
         behave like futureWithResult { test ⇒
           val actor1 = system.actorOf(Props[TestActor])
-          val actor2 = system.actorOf(Props(new Actor { def receive = { case s: String ⇒ sender ! s.toUpperCase } }))
+          val actor2 = system.actorOf(Props(new Actor { def receive = { case s: String ⇒ sender() ! s.toUpperCase } }))
           val future = actor1 ? "Hello" flatMap { case s: String ⇒ actor2 ? s }
           FutureSpec.ready(future, timeout.duration)
           test(future, "WORLD")
@@ -212,7 +212,7 @@ class FutureSpec extends AkkaSpec with Checkers with BeforeAndAfterAll with Defa
         behave like futureWithException[ArithmeticException] { test ⇒
           filterException[ArithmeticException] {
             val actor1 = system.actorOf(Props[TestActor])
-            val actor2 = system.actorOf(Props(new Actor { def receive = { case s: String ⇒ sender ! Status.Failure(new ArithmeticException("/ by zero")) } }))
+            val actor2 = system.actorOf(Props(new Actor { def receive = { case s: String ⇒ sender() ! Status.Failure(new ArithmeticException("/ by zero")) } }))
             val future = actor1 ? "Hello" flatMap { case s: String ⇒ actor2 ? s }
             FutureSpec.ready(future, timeout.duration)
             test(future, "/ by zero")
@@ -225,7 +225,7 @@ class FutureSpec extends AkkaSpec with Checkers with BeforeAndAfterAll with Defa
         behave like futureWithException[NoSuchElementException] { test ⇒
           filterException[NoSuchElementException] {
             val actor1 = system.actorOf(Props[TestActor])
-            val actor2 = system.actorOf(Props(new Actor { def receive = { case s: String ⇒ sender ! s.toUpperCase } }))
+            val actor2 = system.actorOf(Props(new Actor { def receive = { case s: String ⇒ sender() ! s.toUpperCase } }))
             val future = actor1 ? "Hello" flatMap { case i: Int ⇒ actor2 ? i }
             FutureSpec.ready(future, timeout.duration)
             test(future, "World (of class java.lang.String)")
@@ -242,8 +242,8 @@ class FutureSpec extends AkkaSpec with Checkers with BeforeAndAfterAll with Defa
         filterException[ClassCastException] {
           val actor = system.actorOf(Props(new Actor {
             def receive = {
-              case s: String ⇒ sender ! s.length
+              case s: String ⇒ sender() ! s.length
-              case i: Int    ⇒ sender ! (i * 2).toString
+              case i: Int    ⇒ sender() ! (i * 2).toString
             }
           }))
 
@@ -272,8 +272,8 @@ class FutureSpec extends AkkaSpec with Checkers with BeforeAndAfterAll with Defa
         filterException[NoSuchElementException] {
           val actor = system.actorOf(Props(new Actor {
             def receive = {
-              case Req(s: String) ⇒ sender ! Res(s.length)
+              case Req(s: String) ⇒ sender() ! Res(s.length)
-              case Req(i: Int)    ⇒ sender ! Res((i * 2).toString)
+              case Req(i: Int)    ⇒ sender() ! Res((i * 2).toString)
             }
           }))
 
@@ -474,7 +474,7 @@ class FutureSpec extends AkkaSpec with Checkers with BeforeAndAfterAll with Defa
           var counter = 1
           def receive = {
             case 'GetNext ⇒
-              sender ! counter
+              sender() ! counter
               counter += 2
           }
         }))

akka-actor-tests/src/test/scala/akka/dispatch/MailboxConfigSpec.scala

@@ -260,7 +260,7 @@ class SingleConsumerOnlyMailboxVerificationSpec extends AkkaSpec(SingleConsumerO
             def receive = {
               case Ping ⇒
                 n -= 1
-                sender ! Ping
+                sender() ! Ping
                 if (n == 0)
                   context stop self
             }

akka-actor-tests/src/test/scala/akka/dispatch/PriorityDispatcherSpec.scala

@@ -66,7 +66,7 @@ class PriorityDispatcherSpec extends AkkaSpec(PriorityDispatcherSpec.config) wit
 
         def receive = {
           case i: Int  ⇒ acc += i
-          case 'Result ⇒ sender ! acc.toList
+          case 'Result ⇒ sender() ! acc.toList
         }
       }).withDispatcher(dispatcherKey))
 

akka-actor-tests/src/test/scala/akka/event/EventStreamSpec.scala

@@ -43,7 +43,7 @@ object EventStreamSpec {
       case Logging.InitializeLogger(bus) ⇒
         bus.subscribe(context.self, classOf[SetTarget])
         bus.subscribe(context.self, classOf[UnhandledMessage])
-        sender ! Logging.LoggerInitialized
+        sender() ! Logging.LoggerInitialized
       case SetTarget(ref)      ⇒ { dst = ref; dst ! "OK" }
       case e: Logging.LogEvent ⇒ dst ! e
       case u: UnhandledMessage ⇒ dst ! u

akka-actor-tests/src/test/scala/akka/event/LoggerSpec.scala

@@ -78,7 +78,7 @@ object LoggerSpec {
     override def receive: Receive = {
       case InitializeLogger(bus) ⇒
         bus.subscribe(context.self, classOf[SetTarget])
-        sender ! LoggerInitialized
+        sender() ! LoggerInitialized
       case SetTarget(ref, `qualifier`) ⇒
         target = Some(ref)
         ref ! ("OK")

akka-actor-tests/src/test/scala/akka/event/LoggingReceiveSpec.scala

@@ -82,7 +82,7 @@ class LoggingReceiveSpec extends WordSpec with BeforeAndAfterEach with BeforeAnd
         val actor = TestActorRef(new Actor {
           def switch: Actor.Receive = { case "becomenull" ⇒ context.become(r, false) }
           def receive = switch orElse LoggingReceive {
-            case x ⇒ sender ! "x"
+            case x ⇒ sender() ! "x"
           }
         })
 
@@ -110,7 +110,7 @@ class LoggingReceiveSpec extends WordSpec with BeforeAndAfterEach with BeforeAnd
         system.eventStream.subscribe(testActor, classOf[Logging.Debug])
         val actor = TestActorRef(new Actor {
           def receive = LoggingReceive(LoggingReceive {
-            case _ ⇒ sender ! "x"
+            case _ ⇒ sender() ! "x"
           })
         })
         actor ! "buh"

akka-actor-tests/src/test/scala/akka/io/TcpIntegrationSpecSupport.scala

@@ -31,13 +31,13 @@ trait TcpIntegrationSpecSupport { _: AkkaSpec ⇒
       connectCommander.send(IO(Tcp), Connect(endpoint, options = connectOptions))
       val Connected(`endpoint`, localAddress) = connectCommander.expectMsgType[Connected]
       val clientHandler = TestProbe()
-      connectCommander.sender ! Register(clientHandler.ref)
+      connectCommander.sender() ! Register(clientHandler.ref)
 
       val Connected(`localAddress`, `endpoint`) = bindHandler.expectMsgType[Connected]
       val serverHandler = TestProbe()
-      bindHandler.sender ! Register(serverHandler.ref)
+      bindHandler.sender() ! Register(serverHandler.ref)
 
-      (clientHandler, connectCommander.sender, serverHandler, bindHandler.sender)
+      (clientHandler, connectCommander.sender(), serverHandler, bindHandler.sender())
     }
 
     @tailrec final def expectReceivedData(handler: TestProbe, remaining: Int): Unit =

akka-actor-tests/src/test/scala/akka/io/UdpConnectedIntegrationSpec.scala

@@ -20,14 +20,14 @@ class UdpConnectedIntegrationSpec extends AkkaSpec("""
     val commander = TestProbe()
     commander.send(IO(Udp), Udp.Bind(handler, address))
     commander.expectMsg(Udp.Bound(address))
-    commander.sender
+    commander.sender()
   }
 
   def connectUdp(localAddress: Option[InetSocketAddress], remoteAddress: InetSocketAddress, handler: ActorRef): ActorRef = {
     val commander = TestProbe()
     commander.send(IO(UdpConnected), UdpConnected.Connect(handler, remoteAddress, localAddress, Nil))
     commander.expectMsg(UdpConnected.Connected)
-    commander.sender
+    commander.sender()
   }
 
   "The UDP connection oriented implementation" must {

akka-actor-tests/src/test/scala/akka/io/UdpIntegrationSpec.scala

@@ -20,14 +20,14 @@ class UdpIntegrationSpec extends AkkaSpec("""
     val commander = TestProbe()
     commander.send(IO(Udp), Bind(handler, address))
     commander.expectMsg(Bound(address))
-    commander.sender
+    commander.sender()
   }
 
   val simpleSender: ActorRef = {
     val commander = TestProbe()
     commander.send(IO(Udp), SimpleSender)
     commander.expectMsg(SimpleSenderReady)
-    commander.sender
+    commander.sender()
   }
 
   "The UDP Fire-and-Forget implementation" must {

akka-actor-tests/src/test/scala/akka/oldrouting/ConfiguredLocalRoutingSpec.scala

@@ -62,7 +62,7 @@ class ConfiguredLocalRoutingSpec extends AkkaSpec(ConfiguredLocalRoutingSpec.con
     "be picked up from Props" in {
       val actor = system.actorOf(Props(new Actor {
         def receive = {
-          case "get" ⇒ sender ! context.props
+          case "get" ⇒ sender() ! context.props
         }
       }).withRouter(RoundRobinRouter(12)), "someOther")
       routerConfig(actor) should equal(RoundRobinRouter(12))
@@ -72,7 +72,7 @@ class ConfiguredLocalRoutingSpec extends AkkaSpec(ConfiguredLocalRoutingSpec.con
     "be overridable in config" in {
       val actor = system.actorOf(Props(new Actor {
         def receive = {
-          case "get" ⇒ sender ! context.props
+          case "get" ⇒ sender() ! context.props
         }
       }).withRouter(RoundRobinRouter(12)), "config")
       routerConfig(actor) should equal(RandomPool(4))
@@ -82,7 +82,7 @@ class ConfiguredLocalRoutingSpec extends AkkaSpec(ConfiguredLocalRoutingSpec.con
     "be overridable in explicit deployment" in {
       val actor = system.actorOf(Props(new Actor {
         def receive = {
-          case "get" ⇒ sender ! context.props
+          case "get" ⇒ sender() ! context.props
         }
       }).withRouter(FromConfig).withDeploy(Deploy(routerConfig = RoundRobinRouter(12))), "someOther")
       routerConfig(actor) should equal(RoundRobinRouter(12))
@@ -92,7 +92,7 @@ class ConfiguredLocalRoutingSpec extends AkkaSpec(ConfiguredLocalRoutingSpec.con
     "be overridable in config even with explicit deployment" in {
       val actor = system.actorOf(Props(new Actor {
         def receive = {
-          case "get" ⇒ sender ! context.props
+          case "get" ⇒ sender() ! context.props
         }
       }).withRouter(FromConfig).withDeploy(Deploy(routerConfig = RoundRobinRouter(12))), "config")
       routerConfig(actor) should equal(RandomPool(4))
@@ -159,7 +159,7 @@ class ConfiguredLocalRoutingSpec extends AkkaSpec(ConfiguredLocalRoutingSpec.con
       val actor = system.actorOf(Props(new Actor {
         lazy val id = counter.getAndIncrement()
         def receive = {
-          case "hit" ⇒ sender ! id
+          case "hit" ⇒ sender() ! id
           case "end" ⇒ doneLatch.countDown()
         }
       }).withRouter(RoundRobinRouter(connectionCount)), "round-robin")
@@ -208,7 +208,7 @@ class ConfiguredLocalRoutingSpec extends AkkaSpec(ConfiguredLocalRoutingSpec.con
 
       val actor = system.actorOf(Props(new Actor {
         def receive = {
-          case "hello" ⇒ sender ! "world"
+          case "hello" ⇒ sender() ! "world"
         }
 
         override def postStop() {
@@ -244,7 +244,7 @@ class ConfiguredLocalRoutingSpec extends AkkaSpec(ConfiguredLocalRoutingSpec.con
       val actor = system.actorOf(Props(new Actor {
         lazy val id = counter.getAndIncrement()
         def receive = {
-          case "hit" ⇒ sender ! id
+          case "hit" ⇒ sender() ! id
           case "end" ⇒ doneLatch.countDown()
         }
       }).withRouter(RandomRouter(connectionCount)), "random")

akka-actor-tests/src/test/scala/akka/oldrouting/ConsistentHashingRouterSpec.scala

@@ -35,7 +35,7 @@ object ConsistentHashingRouterSpec {
 
   class Echo extends Actor {
     def receive = {
-      case _ ⇒ sender ! self
+      case _ ⇒ sender() ! self
     }
   }
 

akka-actor-tests/src/test/scala/akka/oldrouting/ResizerSpec.scala

@@ -144,8 +144,8 @@ class ResizerSpec extends AkkaSpec(ResizerSpec.config) with DefaultTimeout with
       val router = system.actorOf(Props(new Actor {
         def receive = {
           case d: FiniteDuration ⇒
-            Thread.sleep(d.dilated.toMillis); sender ! "done"
+            Thread.sleep(d.dilated.toMillis); sender() ! "done"
-          case "echo" ⇒ sender ! "reply"
+          case "echo" ⇒ sender() ! "reply"
         }
       }).withRouter(RoundRobinRouter(resizer = Some(resizer))))
 

akka-actor-tests/src/test/scala/akka/oldrouting/RoutingSpec.scala

@@ -47,7 +47,7 @@ object RoutingSpec {
 
   class Echo extends Actor {
     def receive = {
-      case _ ⇒ sender ! self
+      case _ ⇒ sender() ! self
     }
   }
 
@@ -224,8 +224,8 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
         def receive = {
           case "start" ⇒
             context.actorOf(Props(new Actor {
-              def receive = { case x ⇒ sender ! x }
+              def receive = { case x ⇒ sender() ! x }
-            }).withRouter(RoundRobinRouter(2))) ? "hello" pipeTo sender
+            }).withRouter(RoundRobinRouter(2))) ? "hello" pipeTo sender()
         }
       })) ! "start"
       expectMsg("hello")
@@ -470,7 +470,7 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
           case "end" ⇒ doneLatch.countDown()
           case msg: Int ⇒
             counter1.addAndGet(msg)
-            sender ! "ack"
+            sender() ! "ack"
         }
       }))
 
@@ -552,7 +552,7 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
         case _id: Int if (_id == id)        ⇒
         case x ⇒ {
           Thread sleep 100 * id
-          sender ! id
+          sender() ! id
         }
       }
 

akka-actor-tests/src/test/scala/akka/pattern/AskSpec.scala

@@ -49,7 +49,7 @@ class AskSpec extends AkkaSpec {
 
     "return broken promises on 0 timeout" in {
       implicit val timeout = Timeout(0 seconds)
-      val echo = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender ! x } }))
+      val echo = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender() ! x } }))
       val f = echo ? "foo"
       val expectedMsg = "Timeout length must not be negative, question not sent to [%s]" format echo
       intercept[IllegalArgumentException] {
@@ -59,7 +59,7 @@ class AskSpec extends AkkaSpec {
 
     "return broken promises on < 0 timeout" in {
       implicit val timeout = Timeout(-1000 seconds)
-      val echo = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender ! x } }))
+      val echo = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender() ! x } }))
       val f = echo ? "foo"
       val expectedMsg = "Timeout length must not be negative, question not sent to [%s]" format echo
       intercept[IllegalArgumentException] {
@@ -87,7 +87,7 @@ class AskSpec extends AkkaSpec {
     "work for ActorSelection" in {
       implicit val timeout = Timeout(5 seconds)
       import system.dispatcher
-      val echo = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender ! x } }), "select-echo")
+      val echo = system.actorOf(Props(new Actor { def receive = { case x ⇒ sender() ! x } }), "select-echo")
       val identityFuture = (system.actorSelection("/user/select-echo") ? Identify(None))
         .mapTo[ActorIdentity].map(_.ref.get)
 

akka-actor-tests/src/test/scala/akka/pattern/PipeToSpec.scala

@@ -27,7 +27,7 @@ class PipeToSpec extends AkkaSpec {
       p.expectMsgType[Status.Failure].cause.getMessage should be("failed")
     }
 
-    "pick up an implicit sender" in {
+    "pick up an implicit sender()" in {
       val p = TestProbe()
       implicit val s = testActor
       Future(42) pipeTo p.ref
@@ -41,7 +41,7 @@ class PipeToSpec extends AkkaSpec {
       p.expectMsg(42)
     }
 
-    "work in Java form with sender" in {
+    "work in Java form with sender()" in {
       val p = TestProbe()
       pipe(Future(42)) to (p.ref, testActor)
       p.expectMsg(42)
@@ -66,7 +66,7 @@ class PipeToSpec extends AkkaSpec {
       p.expectMsgType[Status.Failure].cause.getMessage should be("failed")
     }
 
-    "pick up an implicit sender" in {
+    "pick up an implicit sender()" in {
       val p = TestProbe()
       val sel = system.actorSelection(p.ref.path)
       implicit val s = testActor
@@ -82,7 +82,7 @@ class PipeToSpec extends AkkaSpec {
       p.expectMsg(42)
     }
 
-    "work in Java form with sender" in {
+    "work in Java form with sender()" in {
       val p = TestProbe()
       val sel = system.actorSelection(p.ref.path)
       pipe(Future(42)) to (sel, testActor)

akka-actor-tests/src/test/scala/akka/performance/microbench/TellLatencyPerformanceSpec.scala

@@ -93,7 +93,7 @@ object TellLatencyPerformanceSpec {
 
   class Destination extends Actor {
     def receive = {
-      case msg: Msg ⇒ sender ! msg
+      case msg: Msg ⇒ sender() ! msg
     }
   }
 

akka-actor-tests/src/test/scala/akka/performance/microbench/TellThroughputComputationPerformanceSpec.scala

@@ -154,7 +154,7 @@ object TellThroughputComputationPerformanceSpec {
     def receive = {
       case Msg ⇒
         calculatePi()
-        sender ! Msg
+        sender() ! Msg
     }
   }
 

akka-actor-tests/src/test/scala/akka/performance/microbench/TellThroughputPerformanceSpec.scala

@@ -141,13 +141,13 @@ object TellThroughputPerformanceSpec {
 
   class Destination1 extends Actor {
     def receive = {
-      case Msg ⇒ sender ! Msg
+      case Msg ⇒ sender() ! Msg
     }
   }
 
   class Destination2 extends Actor {
     def receive = {
-      case Msg ⇒ sender ! Msg
+      case Msg ⇒ sender() ! Msg
     }
   }
 

akka-actor-tests/src/test/scala/akka/performance/trading/system/MatchingEngine.scala

@@ -43,7 +43,7 @@ class AkkaMatchingEngine(val meId: String, val orderbooks: List[Orderbook])
 
   def done(status: Boolean, order: Order) {
     if (standby.isEmpty) {
-      sender ! Rsp(order, status)
+      sender() ! Rsp(order, status)
     }
   }
 

akka-actor-tests/src/test/scala/akka/performance/trading/system/OrderReceiver.scala

@@ -41,7 +41,7 @@ class AkkaOrderReceiver extends Actor with OrderReceiver with ActorLogging {
         m forward order
       case None ⇒
         log.warning("Unknown orderbook: " + order.orderbookSymbol)
-        sender ! Rsp(order, false)
+        sender() ! Rsp(order, false)
     }
   }
 }

akka-actor-tests/src/test/scala/akka/routing/BroadcastSpec.scala

@@ -61,7 +61,7 @@ class BroadcastSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
           case "end" ⇒ doneLatch.countDown()
           case msg: Int ⇒
             counter1.addAndGet(msg)
-            sender ! "ack"
+            sender() ! "ack"
         }
       }))
 

akka-actor-tests/src/test/scala/akka/routing/ConfiguredLocalRoutingSpec.scala

@@ -71,7 +71,7 @@ object ConfiguredLocalRoutingSpec {
 
   class EchoProps extends Actor {
     def receive = {
-      case "get" ⇒ sender ! context.props
+      case "get" ⇒ sender() ! context.props
     }
   }
 

akka-actor-tests/src/test/scala/akka/routing/ConsistentHashingRouterSpec.scala

@@ -32,8 +32,8 @@ object ConsistentHashingRouterSpec {
 
   class Echo extends Actor {
     def receive = {
-      case x: ConsistentHashableEnvelope ⇒ sender ! s"Unexpected envelope: $x"
+      case x: ConsistentHashableEnvelope ⇒ sender() ! s"Unexpected envelope: $x"
-      case _                             ⇒ sender ! self
+      case _                             ⇒ sender() ! self
     }
   }
 

akka-actor-tests/src/test/scala/akka/routing/RandomSpec.scala

@@ -21,7 +21,7 @@ class RandomSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
 
       val actor = system.actorOf(RandomPool(7).props(Props(new Actor {
         def receive = {
-          case "hello" ⇒ sender ! "world"
+          case "hello" ⇒ sender() ! "world"
         }
 
         override def postStop() {
@@ -58,7 +58,7 @@ class RandomSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
         Props(new Actor {
           lazy val id = counter.getAndIncrement()
           def receive = {
-            case "hit" ⇒ sender ! id
+            case "hit" ⇒ sender() ! id
             case "end" ⇒ doneLatch.countDown()
           }
         })), name = "random")

akka-actor-tests/src/test/scala/akka/routing/ResizerSpec.scala

@@ -144,8 +144,8 @@ class ResizerSpec extends AkkaSpec(ResizerSpec.config) with DefaultTimeout with
         Props(new Actor {
           def receive = {
             case d: FiniteDuration ⇒
-              Thread.sleep(d.dilated.toMillis); sender ! "done"
+              Thread.sleep(d.dilated.toMillis); sender() ! "done"
-            case "echo" ⇒ sender ! "reply"
+            case "echo" ⇒ sender() ! "reply"
           }
         })))
 

akka-actor-tests/src/test/scala/akka/routing/RoundRobinSpec.scala

@@ -58,7 +58,7 @@ class RoundRobinSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
       val actor = system.actorOf(RoundRobinPool(connectionCount).props(routeeProps = Props(new Actor {
         lazy val id = counter.getAndIncrement()
         def receive = {
-          case "hit" ⇒ sender ! id
+          case "hit" ⇒ sender() ! id
           case "end" ⇒ doneLatch.countDown()
         }
       })), "round-robin")
@@ -128,7 +128,7 @@ class RoundRobinSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
       val paths = (1 to connectionCount) map { n ⇒
         val ref = system.actorOf(Props(new Actor {
           def receive = {
-            case "hit" ⇒ sender ! self.path.name
+            case "hit" ⇒ sender() ! self.path.name
             case "end" ⇒ doneLatch.countDown()
           }
         }), name = "target-" + n)
@@ -170,13 +170,13 @@ class RoundRobinSpec extends AkkaSpec with DefaultTimeout with ImplicitSender {
             router = router.removeRoutee(c)
             if (router.routees.isEmpty)
               context.stop(self)
-          case other ⇒ router.route(other, sender)
+          case other ⇒ router.route(other, sender())
         }
       }))
 
       val childProps = Props(new Actor {
         def receive = {
-          case "hit" ⇒ sender ! self.path.name
+          case "hit" ⇒ sender() ! self.path.name
           case "end" ⇒ context.stop(self)
         }
       })

akka-actor-tests/src/test/scala/akka/routing/RoutingSpec.scala

@@ -47,7 +47,7 @@ object RoutingSpec {
 
   class Echo extends Actor {
     def receive = {
-      case _ ⇒ sender ! self
+      case _ ⇒ sender() ! self
     }
   }
 
@@ -202,8 +202,8 @@ class RoutingSpec extends AkkaSpec(RoutingSpec.config) with DefaultTimeout with
         def receive = {
           case "start" ⇒
             context.actorOf(RoundRobinPool(2).props(routeeProps = Props(new Actor {
-              def receive = { case x ⇒ sender ! x }
+              def receive = { case x ⇒ sender() ! x }
-            }))) ? "hello" pipeTo sender
+            }))) ? "hello" pipeTo sender()
         }
       })) ! "start"
       expectMsg("hello")

akka-actor-tests/src/test/scala/akka/routing/ScatterGatherFirstCompletedSpec.scala

@@ -26,7 +26,7 @@ object ScatterGatherFirstCompletedSpec {
         case _id: Int if (_id == id)        ⇒
         case x ⇒ {
           Thread sleep 100 * id
-          sender ! id
+          sender() ! id
         }
       }
 

akka-actor-tests/src/test/scala/akka/serialization/SerializeSpec.scala

@@ -83,7 +83,7 @@ object SerializationTests {
 
   class FooActor extends Actor {
     def receive = {
-      case s: String ⇒ sender ! s
+      case s: String ⇒ sender() ! s
     }
   }
 
@@ -93,7 +93,7 @@ object SerializationTests {
 
   class NonSerializableActor(system: ActorSystem) extends Actor {
     def receive = {
-      case s: String ⇒ sender ! s
+      case s: String ⇒ sender() ! s
     }
   }
 

akka-actor/src/main/scala/akka/actor/Actor.scala

@@ -356,7 +356,7 @@ object Actor {
  *  - ''SHUTDOWN'' (when 'stop' is invoked) - can't do anything
  *
  * The Actor's own [[akka.actor.ActorRef]] is available as `self`, the current
- * message’s sender as `sender` and the [[akka.actor.ActorContext]] as
+ * message’s sender as `sender()` and the [[akka.actor.ActorContext]] as
  * `context`. The only abstract method is `receive` which shall return the
  * initial behavior of the actor as a partial function (behavior can be changed
  * using `context.become` and `context.unbecome`).
@@ -375,23 +375,23 @@ object Actor {
  *
  *   def receive = {
  *                                      // directly calculated reply
- *     case Request(r)               => sender ! calculate(r)
+ *     case Request(r)               => sender() ! calculate(r)
  *
  *                                      // just to demonstrate how to stop yourself
  *     case Shutdown                 => context.stop(self)
  *
- *                                      // error kernel with child replying directly to 'sender'
+ *                                      // error kernel with child replying directly to 'sender()'
- *     case Dangerous(r)             => context.actorOf(Props[ReplyToOriginWorker]).tell(PerformWork(r), sender)
+ *     case Dangerous(r)             => context.actorOf(Props[ReplyToOriginWorker]).tell(PerformWork(r), sender())
  *
  *                                      // error kernel with reply going through us
- *     case OtherJob(r)              => context.actorOf(Props[ReplyToMeWorker]) ! JobRequest(r, sender)
+ *     case OtherJob(r)              => context.actorOf(Props[ReplyToMeWorker]) ! JobRequest(r, sender())
  *     case JobReply(result, orig_s) => orig_s ! result
  *   }
  * }
  * }}}
  *
  * The last line demonstrates the essence of the error kernel design: spawn
- * one-off actors which terminate after doing their job, pass on `sender` to
+ * one-off actors which terminate after doing their job, pass on `sender()` to
  * allow direct reply if that is what makes sense, or round-trip the sender
  * as shown with the fictitious JobRequest/JobReply message pair.
  *
@@ -446,7 +446,7 @@ trait Actor {
    * WARNING: Only valid within the Actor itself, so do not close over it and
    * publish it to other threads!
    */
-  final def sender: ActorRef = context.sender
+  final def sender(): ActorRef = context.sender()
 
   /**
    * This defines the initial actor behavior, it must return a partial function
@@ -561,7 +561,7 @@ trait Actor {
   def unhandled(message: Any): Unit = {
     message match {
       case Terminated(dead) ⇒ throw new DeathPactException(dead)
-      case _                ⇒ context.system.eventStream.publish(UnhandledMessage(message, sender, self))
+      case _                ⇒ context.system.eventStream.publish(UnhandledMessage(message, sender(), self))
     }
   }
 }

akka-actor/src/main/scala/akka/actor/ActorCell.scala

@@ -91,7 +91,7 @@ trait ActorContext extends ActorRefFactory {
   /**
    * Returns the sender 'ActorRef' of the current message.
    */
-  def sender: ActorRef
+  def sender(): ActorRef
 
   /**
    * Returns all supervised children; this method returns a view (i.e. a lazy
@@ -478,15 +478,15 @@ private[akka] class ActorCell(
       case Kill                       ⇒ throw new ActorKilledException("Kill")
       case PoisonPill                 ⇒ self.stop()
       case sel: ActorSelectionMessage ⇒ receiveSelection(sel)
-      case Identify(messageId)        ⇒ sender ! ActorIdentity(messageId, Some(self))
+      case Identify(messageId)        ⇒ sender() ! ActorIdentity(messageId, Some(self))
     }
   }
 
   private def receiveSelection(sel: ActorSelectionMessage): Unit =
     if (sel.elements.isEmpty)
-      invoke(Envelope(sel.msg, sender, system))
+      invoke(Envelope(sel.msg, sender(), system))
     else
-      ActorSelection.deliverSelection(self, sender, sel)
+      ActorSelection.deliverSelection(self, sender(), sel)
 
   final def receiveMessage(msg: Any): Unit = actor.aroundReceive(behaviorStack.head, msg)
 
@@ -494,7 +494,7 @@ private[akka] class ActorCell(
    * ACTOR CONTEXT IMPLEMENTATION
    */
 
-  final def sender: ActorRef = currentMessage match {
+  final def sender(): ActorRef = currentMessage match {
     case null                      ⇒ system.deadLetters
     case msg if msg.sender ne null ⇒ msg.sender
     case _                         ⇒ system.deadLetters

akka-actor/src/main/scala/akka/actor/ActorDSL.scala

@@ -90,7 +90,7 @@ object ActorDSL extends dsl.Inbox with dsl.Creators {
 
     val boss = system.asInstanceOf[ActorSystemImpl].systemActorOf(Props(
       new Actor {
-        def receive = { case any ⇒ sender ! any }
+        def receive = { case any ⇒ sender() ! any }
       }), "dsl").asInstanceOf[RepointableActorRef]
 
     {

akka-actor/src/main/scala/akka/actor/ActorRef.scala

@@ -45,10 +45,10 @@ object ActorRef {
  *
  *   def receive {
  *     case Request1(msg) => other ! refine(msg)     // uses this actor as sender reference, reply goes to us
- *     case Request2(msg) => other.tell(msg, sender) // forward sender reference, enabling direct reply
+ *     case Request2(msg) => other.tell(msg, sender()) // forward sender reference, enabling direct reply
  *     case Request3(msg) =>
  *       implicit val timeout = Timeout(5.seconds)
- *       sender ! (other ? msg)  // will reply with a Future for holding other's reply
+ *       sender() ! (other ? msg)  // will reply with a Future for holding other's reply
  *   }
  * }
  * }}}
@@ -127,7 +127,7 @@ abstract class ActorRef extends java.lang.Comparable[ActorRef] with Serializable
    *
    * Works, no matter whether originally sent with tell/'!' or ask/'?'.
    */
-  def forward(message: Any)(implicit context: ActorContext) = tell(message, context.sender)
+  def forward(message: Any)(implicit context: ActorContext) = tell(message, context.sender())
 
   /**
    * Is the actor shut down?
@@ -168,7 +168,7 @@ trait ScalaActorRef { ref: ActorRef ⇒
    * If invoked from within an actor then the actor reference is implicitly passed on as the implicit 'sender' argument.
    * <p/>
    *
-   * This actor 'sender' reference is then available in the receiving actor in the 'sender' member variable,
+   * This actor 'sender' reference is then available in the receiving actor in the 'sender()' member variable,
    * if invoked from within an Actor. If not then no sender is available.
    * <pre>
    *   actor ! message

akka-actor/src/main/scala/akka/actor/ActorRefProvider.scala

@@ -370,7 +370,7 @@ private[akka] object LocalActorRefProvider {
     def receive = {
       case Terminated(_)    ⇒ context.stop(self)
       case StopChild(child) ⇒ context.stop(child)
-      case m                ⇒ context.system.deadLetters forward DeadLetter(m, sender, self)
+      case m                ⇒ context.system.deadLetters forward DeadLetter(m, sender(), self)
     }
 
     // guardian MUST NOT lose its children during restart
@@ -399,16 +399,16 @@ private[akka] object LocalActorRefProvider {
         // termination process of guardian has started
         terminationHooks -= a
       case StopChild(child) ⇒ context.stop(child)
-      case RegisterTerminationHook if sender != context.system.deadLetters ⇒
+      case RegisterTerminationHook if sender() != context.system.deadLetters ⇒
-        terminationHooks += sender
+        terminationHooks += sender()
-        context watch sender
+        context watch sender()
-      case m ⇒ context.system.deadLetters forward DeadLetter(m, sender, self)
+      case m ⇒ context.system.deadLetters forward DeadLetter(m, sender(), self)
     }
 
     def terminating: Receive = {
       case Terminated(a)       ⇒ stopWhenAllTerminationHooksDone(a)
-      case TerminationHookDone ⇒ stopWhenAllTerminationHooksDone(sender)
+      case TerminationHookDone ⇒ stopWhenAllTerminationHooksDone(sender())
-      case m                   ⇒ context.system.deadLetters forward DeadLetter(m, sender, self)
+      case m                   ⇒ context.system.deadLetters forward DeadLetter(m, sender(), self)
     }
 
     def stopWhenAllTerminationHooksDone(remove: ActorRef): Unit = {

akka-actor/src/main/scala/akka/actor/ActorSelection.scala

@@ -45,7 +45,7 @@ abstract class ActorSelection extends Serializable {
    *
    * Works, no matter whether originally sent with tell/'!' or ask/'?'.
    */
-  def forward(message: Any)(implicit context: ActorContext) = tell(message, context.sender)
+  def forward(message: Any)(implicit context: ActorContext) = tell(message, context.sender())
 
   /**
    * Resolve the [[ActorRef]] matching this selection.

akka-actor/src/main/scala/akka/actor/FSM.scala

@@ -573,7 +573,7 @@ trait FSM[S, D] extends Actor with Listeners with ActorLogging {
         timeoutFuture = None
       }
       generation += 1
-      processMsg(value, sender)
+      processMsg(value, sender())
     }
   }
 
@@ -597,7 +597,7 @@ trait FSM[S, D] extends Actor with Listeners with ActorLogging {
     nextState.stopReason match {
       case None ⇒ makeTransition(nextState)
       case _ ⇒
-        nextState.replies.reverse foreach { r ⇒ sender ! r }
+        nextState.replies.reverse foreach { r ⇒ sender() ! r }
         terminate(nextState)
         context.stop(self)
     }
@@ -607,7 +607,7 @@ trait FSM[S, D] extends Actor with Listeners with ActorLogging {
     if (!stateFunctions.contains(nextState.stateName)) {
       terminate(stay withStopReason Failure("Next state %s does not exist".format(nextState.stateName)))
     } else {
-      nextState.replies.reverse foreach { r ⇒ sender ! r }
+      nextState.replies.reverse foreach { r ⇒ sender() ! r }
       if (currentState.stateName != nextState.stateName) {
         this.nextState = nextState
         handleTransition(currentState.stateName, nextState.stateName)

akka-actor/src/main/scala/akka/actor/TypedActor.scala

@@ -307,7 +307,7 @@ object TypedActor extends ExtensionId[TypedActorExtension] with ExtensionIdProvi
         if (m.isOneWay) m(me)
         else {
           try {
-            val s = sender
+            val s = sender()
             m(me) match {
               case f: Future[_] if m.returnsFuture ⇒
                 implicit val dispatcher = context.dispatcher
@@ -321,14 +321,14 @@ object TypedActor extends ExtensionId[TypedActorExtension] with ExtensionIdProvi
             }
           } catch {
             case NonFatal(e) ⇒
-              sender ! Status.Failure(e)
+              sender() ! Status.Failure(e)
               throw e
           }
         }
       }
 
       case msg if me.isInstanceOf[Receiver] ⇒ withContext {
-        me.asInstanceOf[Receiver].onReceive(msg, sender)
+        me.asInstanceOf[Receiver].onReceive(msg, sender())
       }
     }
   }

akka-actor/src/main/scala/akka/actor/UntypedActor.scala

@@ -120,7 +120,7 @@ abstract class UntypedActor extends Actor {
    * always a legal destination to send to, even if there is no logical recipient
    * for the reply, in which case it will be sent to the dead letter mailbox.
    */
-  def getSender(): ActorRef = sender
+  def getSender(): ActorRef = sender()
 
   /**
    * User overridable definition the strategy to use for supervising

akka-actor/src/main/scala/akka/actor/dsl/Inbox.scala

@@ -66,7 +66,7 @@ trait Inbox { this: ActorDSL.type ⇒
     var printedWarning = false
 
     def enqueueQuery(q: Query) {
-      val query = q withClient sender
+      val query = q withClient sender()
       clients enqueue query
       clientsByTimeout += query
     }
@@ -96,13 +96,13 @@ trait Inbox { this: ActorDSL.type ⇒
     def receive = ({
       case g: Get ⇒
         if (messages.isEmpty) enqueueQuery(g)
-        else sender ! messages.dequeue()
+        else sender() ! messages.dequeue()
       case s @ Select(_, predicate, _) ⇒
         if (messages.isEmpty) enqueueQuery(s)
         else {
           currentSelect = s
           messages.dequeueFirst(messagePredicate) match {
-            case Some(msg) ⇒ sender ! msg
+            case Some(msg) ⇒ sender() ! msg
             case None      ⇒ enqueueQuery(s)
           }
           currentSelect = null

akka-actor/src/main/scala/akka/event/Logging.scala

@@ -793,7 +793,7 @@ object Logging {
    */
   class DefaultLogger extends Actor with StdOutLogger {
     override def receive: Receive = {
-      case InitializeLogger(_) ⇒ sender ! LoggerInitialized
+      case InitializeLogger(_) ⇒ sender() ! LoggerInitialized
       case event: LogEvent     ⇒ print(event)
     }
   }

akka-actor/src/main/scala/akka/io/SelectionHandler.scala

@@ -84,7 +84,7 @@ private[io] object SelectionHandler {
       name = "selectors")
 
     final def workerForCommandHandler(pf: PartialFunction[HasFailureMessage, ChannelRegistry ⇒ Props]): Receive = {
-      case cmd: HasFailureMessage if pf.isDefinedAt(cmd) ⇒ selectorPool ! WorkerForCommand(cmd, sender, pf(cmd))
+      case cmd: HasFailureMessage if pf.isDefinedAt(cmd) ⇒ selectorPool ! WorkerForCommand(cmd, sender(), pf(cmd))
     }
   }
 

akka-actor/src/main/scala/akka/io/TcpConnection.scala

@@ -61,7 +61,7 @@ private[io] abstract class TcpConnection(val tcp: TcpExt, val channel: SocketCha
 
     case cmd: CloseCommand ⇒
       val info = ConnectionInfo(registration, commander, keepOpenOnPeerClosed = false, useResumeWriting = false)
-      handleClose(info, Some(sender), cmd.event)
+      handleClose(info, Some(sender()), cmd.event)
 
     case ReceiveTimeout ⇒
       // after sending `Register` user should watch this actor to make sure
@@ -76,13 +76,13 @@ private[io] abstract class TcpConnection(val tcp: TcpExt, val channel: SocketCha
       case SuspendReading    ⇒ suspendReading(info)
       case ResumeReading     ⇒ resumeReading(info)
       case ChannelReadable   ⇒ doRead(info, None)
-      case cmd: CloseCommand ⇒ handleClose(info, Some(sender), cmd.event)
+      case cmd: CloseCommand ⇒ handleClose(info, Some(sender()), cmd.event)
     }
 
   /** the peer sent EOF first, but we may still want to send */
   def peerSentEOF(info: ConnectionInfo): Receive =
     handleWriteMessages(info) orElse {
-      case cmd: CloseCommand ⇒ handleClose(info, Some(sender), cmd.event)
+      case cmd: CloseCommand ⇒ handleClose(info, Some(sender()), cmd.event)
     }
 
   /** connection is closing but a write has to be finished first */
@@ -104,7 +104,7 @@ private[io] abstract class TcpConnection(val tcp: TcpExt, val channel: SocketCha
 
     case WriteFileFailed(e) ⇒ handleError(info.handler, e) // rethrow exception from dispatcher task
 
-    case Abort              ⇒ handleClose(info, Some(sender), Aborted)
+    case Abort              ⇒ handleClose(info, Some(sender()), Aborted)
   }
 
   /** connection is closed on our side and we're waiting from confirmation from the other side */
@@ -112,7 +112,7 @@ private[io] abstract class TcpConnection(val tcp: TcpExt, val channel: SocketCha
     case SuspendReading  ⇒ suspendReading(info)
     case ResumeReading   ⇒ resumeReading(info)
     case ChannelReadable ⇒ doRead(info, closeCommander)
-    case Abort           ⇒ handleClose(info, Some(sender), Aborted)
+    case Abort           ⇒ handleClose(info, Some(sender()), Aborted)
   }
 
   def handleWriteMessages(info: ConnectionInfo): Receive = {
@@ -128,15 +128,15 @@ private[io] abstract class TcpConnection(val tcp: TcpExt, val channel: SocketCha
     case write: WriteCommand ⇒
       if (writingSuspended) {
         if (TraceLogging) log.debug("Dropping write because writing is suspended")
-        sender ! write.failureMessage
+        sender() ! write.failureMessage
 
       } else if (writePending) {
         if (TraceLogging) log.debug("Dropping write because queue is full")
-        sender ! write.failureMessage
+        sender() ! write.failureMessage
         if (info.useResumeWriting) writingSuspended = true
 
       } else {
-        pendingWrite = PendingWrite(sender, write)
+        pendingWrite = PendingWrite(sender(), write)
         if (writePending) doWrite(info)
       }
 
@@ -153,9 +153,9 @@ private[io] abstract class TcpConnection(val tcp: TcpExt, val channel: SocketCha
        */
       writingSuspended = false
       if (writePending) {
-        if (interestedInResume.isEmpty) interestedInResume = Some(sender)
+        if (interestedInResume.isEmpty) interestedInResume = Some(sender())
-        else sender ! CommandFailed(ResumeWriting)
+        else sender() ! CommandFailed(ResumeWriting)
-      } else sender ! WritingResumed
+      } else sender() ! WritingResumed
 
     case UpdatePendingWrite(remaining) ⇒
       pendingWrite = remaining

akka-actor/src/main/scala/akka/io/TcpListener.scala

@@ -85,7 +85,7 @@ private[io] class TcpListener(selectorRouter: ActorRef,
     case Unbind ⇒
       log.debug("Unbinding endpoint {}", localAddress)
       channel.close()
-      sender ! Unbound
+      sender() ! Unbound
       log.debug("Unbound endpoint {}, stopping listener", localAddress)
       context.stop(self)
   }

akka-actor/src/main/scala/akka/io/TcpManager.scala

@@ -18,7 +18,7 @@ import akka.actor.{ ActorLogging, Props }
  *
  * To bind and listen to a local address, a [[akka.io.Tcp.Bind]] command must be sent to this actor. If the binding
  * was successful, the sender of the [[akka.io.Tcp.Bind]] will be notified with a [[akka.io.Tcp.Bound]]
- * message. The sender of the [[akka.io.Tcp.Bound]] message is the Listener actor (an internal actor responsible for
+ * message. The sender() of the [[akka.io.Tcp.Bound]] message is the Listener actor (an internal actor responsible for
  * listening to server events). To unbind the port an [[akka.io.Tcp.Unbind]] message must be sent to the Listener actor.
  *
  * If the bind request is rejected because the Tcp system is not able to register more channels (see the nr-of-selectors
@@ -32,7 +32,7 @@ import akka.actor.{ ActorLogging, Props }
  * == Connect ==
  *
  * To initiate a connection to a remote server, a [[akka.io.Tcp.Connect]] message must be sent to this actor. If the
- * connection succeeds, the sender will be notified with a [[akka.io.Tcp.Connected]] message. The sender of the
+ * connection succeeds, the sender() will be notified with a [[akka.io.Tcp.Connected]] message. The sender of the
  * [[akka.io.Tcp.Connected]] message is the Connection actor (an internal actor representing the TCP connection). Before
  * starting to use the connection, a handler must be registered to the Connection actor by sending a [[akka.io.Tcp.Register]]
  * command message. After a handler has been registered, all incoming data will be sent to the handler in the form of
@@ -49,11 +49,11 @@ private[io] class TcpManager(tcp: TcpExt)
 
   def receive = workerForCommandHandler {
     case c: Connect ⇒
-      val commander = sender // cache because we create a function that will run asyncly
+      val commander = sender() // cache because we create a function that will run asyncly
       (registry ⇒ Props(classOf[TcpOutgoingConnection], tcp, registry, commander, c))
 
     case b: Bind ⇒
-      val commander = sender // cache because we create a function that will run asyncly
+      val commander = sender() // cache because we create a function that will run asyncly
       (registry ⇒ Props(classOf[TcpListener], selectorPool, tcp, registry, commander, b))
   }
 

akka-actor/src/main/scala/akka/io/UdpConnectedManager.scala

@@ -14,7 +14,7 @@ private[io] class UdpConnectedManager(udpConn: UdpConnectedExt)
 
   def receive = workerForCommandHandler {
     case c: Connect ⇒
-      val commander = sender // cache because we create a function that will run asyncly
+      val commander = sender() // cache because we create a function that will run asyncly
       registry ⇒ Props(classOf[UdpConnection], udpConn, registry, commander, c)
   }
 

akka-actor/src/main/scala/akka/io/UdpConnection.scala

@@ -65,20 +65,20 @@ private[io] class UdpConnection(udpConn: UdpConnectedExt,
     case Disconnect ⇒
       log.debug("Closing UDP connection to [{}]", remoteAddress)
       channel.close()
-      sender ! Disconnected
+      sender() ! Disconnected
       log.debug("Connection closed to [{}], stopping listener", remoteAddress)
       context.stop(self)
 
     case send: Send if writePending ⇒
       if (TraceLogging) log.debug("Dropping write because queue is full")
-      sender ! CommandFailed(send)
+      sender() ! CommandFailed(send)
 
     case send: Send if send.payload.isEmpty ⇒
       if (send.wantsAck)
-        sender ! send.ack
+        sender() ! send.ack
 
     case send: Send ⇒
-      pendingSend = (send, sender)
+      pendingSend = (send, sender())
       registration.enableInterest(OP_WRITE)
 
     case ChannelWritable ⇒ doWrite()

akka-actor/src/main/scala/akka/io/UdpListener.scala

@@ -68,7 +68,7 @@ private[io] class UdpListener(val udp: UdpExt,
       log.debug("Unbinding endpoint [{}]", bind.localAddress)
       try {
         channel.close()
-        sender ! Unbound
+        sender() ! Unbound
         log.debug("Unbound endpoint [{}], stopping listener", bind.localAddress)
       } finally context.stop(self)
   }

akka-actor/src/main/scala/akka/io/UdpManager.scala

@@ -47,11 +47,11 @@ private[io] class UdpManager(udp: UdpExt) extends SelectionHandler.SelectorBased
 
   def receive = workerForCommandHandler {
     case b: Bind ⇒
-      val commander = sender // cache because we create a function that will run asyncly
+      val commander = sender() // cache because we create a function that will run asyncly
       (registry ⇒ Props(classOf[UdpListener], udp, registry, commander, b))
 
     case SimpleSender(options) ⇒
-      val commander = sender // cache because we create a function that will run asyncly
+      val commander = sender() // cache because we create a function that will run asyncly
       (registry ⇒ Props(classOf[UdpSender], udp, registry, commander, options))
   }
 

akka-actor/src/main/scala/akka/io/WithUdpSend.scala

@@ -30,15 +30,15 @@ private[io] trait WithUdpSend {
   def sendHandlers(registration: ChannelRegistration): Receive = {
     case send: Send if hasWritePending ⇒
       if (TraceLogging) log.debug("Dropping write because queue is full")
-      sender ! CommandFailed(send)
+      sender() ! CommandFailed(send)
 
     case send: Send if send.payload.isEmpty ⇒
       if (send.wantsAck)
-        sender ! send.ack
+        sender() ! send.ack
 
     case send: Send ⇒
       pendingSend = send
-      pendingCommander = sender
+      pendingCommander = sender()
       doSend(registration)
 
     case ChannelWritable ⇒ if (hasWritePending) doSend(registration)

akka-actor/src/main/scala/akka/routing/Listeners.scala

@@ -40,7 +40,7 @@ trait Listeners { self: Actor ⇒
   }
 
   /**
-   * Sends the supplied message to all current listeners using the provided sender as sender.
+   * Sends the supplied message to all current listeners using the provided sender() as sender.
    *
    * @param msg
    * @param sender

akka-actor/src/main/scala/akka/routing/RoutedActorCell.scala

@@ -166,9 +166,9 @@ private[akka] class RouterActor extends Actor {
 
   def receive = {
     case GetRoutees ⇒
-      sender ! Routees(cell.router.routees)
+      sender() ! Routees(cell.router.routees)
     case CurrentRoutees ⇒
-      context.actorOf(Props(classOf[CollectRouteeRefs], cell.router.routees, sender))
+      context.actorOf(Props(classOf[CollectRouteeRefs], cell.router.routees, sender()))
     case AddRoutee(routee) ⇒
       cell.addRoutee(routee)
     case RemoveRoutee(routee) ⇒

akka-camel/src/main/scala/akka/camel/Producer.scala

@@ -77,7 +77,7 @@ trait ProducerSupport extends Actor with CamelSupport {
     case msg ⇒
       producerChild match {
         case Some(child) ⇒ child forward transformOutgoingMessage(msg)
-        case None        ⇒ messages :+= ((sender, msg))
+        case None        ⇒ messages :+= ((sender(), msg))
       }
   }
 
@@ -103,7 +103,7 @@ trait ProducerSupport extends Actor with CamelSupport {
    * actor).
    */
 
-  protected def routeResponse(msg: Any): Unit = if (!oneway) sender ! transformResponse(msg)
+  protected def routeResponse(msg: Any): Unit = if (!oneway) sender() ! transformResponse(msg)
 
   private class ProducerChild(endpoint: Endpoint, processor: SendProcessor) extends Actor {
     def receive = {
@@ -129,7 +129,7 @@ trait ProducerSupport extends Actor with CamelSupport {
       // Need copies of sender reference here since the callback could be done
       // later by another thread.
       val producer = self
-      val originalSender = sender
+      val originalSender = sender()
       val xchg = new CamelExchangeAdapter(endpoint.createExchange(pattern))
       val cmsg = CamelMessage.canonicalize(msg)
       xchg.setRequest(cmsg)

akka-camel/src/main/scala/akka/camel/internal/ActivationTracker.scala

@@ -31,8 +31,8 @@ private[camel] class ActivationTracker extends Actor with ActorLogging {
       var awaitingDeActivation = List[ActorRef]()
 
       {
-        case AwaitActivation(ref)   ⇒ awaitingActivation ::= sender
+        case AwaitActivation(ref)   ⇒ awaitingActivation ::= sender()
-        case AwaitDeActivation(ref) ⇒ awaitingDeActivation ::= sender
+        case AwaitDeActivation(ref) ⇒ awaitingDeActivation ::= sender()
         case msg @ EndpointActivated(ref) ⇒
           awaitingActivation.foreach(_ ! msg)
           receive = activated(awaitingDeActivation)
@@ -51,8 +51,8 @@ private[camel] class ActivationTracker extends Actor with ActorLogging {
       var awaitingDeActivation = currentAwaitingDeActivation
 
       {
-        case AwaitActivation(ref)   ⇒ sender ! EndpointActivated(ref)
+        case AwaitActivation(ref)   ⇒ sender() ! EndpointActivated(ref)
-        case AwaitDeActivation(ref) ⇒ awaitingDeActivation ::= sender
+        case AwaitDeActivation(ref) ⇒ awaitingDeActivation ::= sender()
         case msg @ EndpointDeActivated(ref) ⇒
           awaitingDeActivation foreach (_ ! msg)
           receive = deactivated
@@ -67,9 +67,9 @@ private[camel] class ActivationTracker extends Actor with ActorLogging {
      * @return a partial function that handles messages in the 'de-activated' state
      */
     def deactivated: State = {
-      // deactivated means it was activated at some point, so tell sender it was activated
+      // deactivated means it was activated at some point, so tell sender() it was activated
-      case AwaitActivation(ref)   ⇒ sender ! EndpointActivated(ref)
+      case AwaitActivation(ref)   ⇒ sender() ! EndpointActivated(ref)
-      case AwaitDeActivation(ref) ⇒ sender ! EndpointDeActivated(ref)
+      case AwaitDeActivation(ref) ⇒ sender() ! EndpointDeActivated(ref)
       //resurrected at restart.
       case msg @ EndpointActivated(ref) ⇒
         receive = activated(Nil)
@@ -81,8 +81,8 @@ private[camel] class ActivationTracker extends Actor with ActorLogging {
      * @return a partial function that handles messages in 'failed to activate' state
      */
     def failedToActivate(cause: Throwable): State = {
-      case AwaitActivation(ref)   ⇒ sender ! EndpointFailedToActivate(ref, cause)
+      case AwaitActivation(ref)   ⇒ sender() ! EndpointFailedToActivate(ref, cause)
-      case AwaitDeActivation(ref) ⇒ sender ! EndpointFailedToActivate(ref, cause)
+      case AwaitDeActivation(ref) ⇒ sender() ! EndpointFailedToActivate(ref, cause)
       case EndpointDeActivated(_) ⇒ // the de-register at termination always sends a de-activated when the cleanup is done. ignoring.
     }
 
@@ -92,8 +92,8 @@ private[camel] class ActivationTracker extends Actor with ActorLogging {
      * @return a partial function that handles messages in 'failed to de-activate' state
      */
     def failedToDeActivate(cause: Throwable): State = {
-      case AwaitActivation(ref)   ⇒ sender ! EndpointActivated(ref)
+      case AwaitActivation(ref)   ⇒ sender() ! EndpointActivated(ref)
-      case AwaitDeActivation(ref) ⇒ sender ! EndpointFailedToDeActivate(ref, cause)
+      case AwaitDeActivation(ref) ⇒ sender() ! EndpointFailedToDeActivate(ref, cause)
       case EndpointDeActivated(_) ⇒ // the de-register at termination always sends a de-activated when the cleanup is done. ignoring.
     }
 

akka-camel/src/test/scala/akka/camel/ActivationIntegrationTest.scala

@@ -75,7 +75,7 @@ class ActivationIntegrationTest extends WordSpec with Matchers with SharedCamelS
     }
 
     override def receive = {
-      case msg: CamelMessage ⇒ sender ! "received " + msg.body
+      case msg: CamelMessage ⇒ sender() ! "received " + msg.body
     }
   }
 

akka-camel/src/test/scala/akka/camel/ConcurrentActivationTest.scala

@@ -159,7 +159,7 @@ class EchoConsumer(endpoint: String) extends Actor with Consumer {
   def endpointUri = endpoint
 
   def receive = {
-    case msg: CamelMessage ⇒ sender ! msg
+    case msg: CamelMessage ⇒ sender() ! msg
   }
 
   /**

akka-camel/src/test/scala/akka/camel/ConsumerIntegrationTest.scala

@@ -41,7 +41,7 @@ class ConsumerIntegrationTest extends WordSpec with Matchers with NonSharedCamel
       start(new Consumer {
         def endpointUri = "direct:a1"
         def receive = {
-          case m: CamelMessage ⇒ sender ! "received " + m.bodyAs[String]
+          case m: CamelMessage ⇒ sender() ! "received " + m.bodyAs[String]
         }
       }, name = "direct-a1")
       camel.sendTo("direct:a1", msg = "some message") should be("received some message")
@@ -54,7 +54,7 @@ class ConsumerIntegrationTest extends WordSpec with Matchers with NonSharedCamel
       val ref = start(new Consumer {
         override def replyTimeout = SHORT_TIMEOUT
         def endpointUri = "direct:a3"
-        def receive = { case _ ⇒ { Thread.sleep(LONG_WAIT.toMillis); sender ! "done" } }
+        def receive = { case _ ⇒ { Thread.sleep(LONG_WAIT.toMillis); sender() ! "done" } }
       }, name = "ignore-this-deadletter-timeout-consumer-reply")
 
       intercept[CamelExecutionException] {
@@ -71,7 +71,7 @@ class ConsumerIntegrationTest extends WordSpec with Matchers with NonSharedCamel
 
         def receive = {
           case "throw"         ⇒ throw new TestException("")
-          case m: CamelMessage ⇒ sender ! "received " + m.bodyAs[String]
+          case m: CamelMessage ⇒ sender() ! "received " + m.bodyAs[String]
         }
 
         override def postRestart(reason: Throwable) {
@@ -138,7 +138,7 @@ class ConsumerIntegrationTest extends WordSpec with Matchers with NonSharedCamel
     "Consumer supports manual Ack" in {
       val ref = start(new ManualAckConsumer() {
         def endpointUri = "direct:manual-ack"
-        def receive = { case _ ⇒ sender ! Ack }
+        def receive = { case _ ⇒ sender() ! Ack }
       }, name = "direct-manual-ack-1")
       camel.template.asyncSendBody("direct:manual-ack", "some message").get(defaultTimeoutDuration.toSeconds, TimeUnit.SECONDS) should be(null) //should not timeout
       stop(ref)
@@ -148,7 +148,7 @@ class ConsumerIntegrationTest extends WordSpec with Matchers with NonSharedCamel
       val someException = new Exception("e1")
       val ref = start(new ManualAckConsumer() {
         def endpointUri = "direct:manual-ack"
-        def receive = { case _ ⇒ sender ! Failure(someException) }
+        def receive = { case _ ⇒ sender() ! Failure(someException) }
       }, name = "direct-manual-ack-2")
 
       intercept[ExecutionException] {
@@ -186,7 +186,7 @@ class ErrorThrowingConsumer(override val endpointUri: String) extends Consumer {
   }
   override def preRestart(reason: Throwable, message: Option[Any]) {
     super.preRestart(reason, message)
-    sender ! Failure(reason)
+    sender() ! Failure(reason)
   }
 }
 
@@ -201,7 +201,7 @@ class ErrorRespondingConsumer(override val endpointUri: String) extends Consumer
 
   final override def preRestart(reason: Throwable, message: Option[Any]) {
     super.preRestart(reason, message)
-    sender ! Failure(reason)
+    sender() ! Failure(reason)
   }
 }
 
@@ -210,14 +210,14 @@ class FailingOnceConsumer(override val endpointUri: String) extends Consumer {
   def receive = {
     case msg: CamelMessage ⇒
       if (msg.headerAs[Boolean]("CamelRedelivered").getOrElse(false))
-        sender ! ("accepted: %s" format msg.body)
+        sender() ! ("accepted: %s" format msg.body)
       else
         throw new TestException("rejected: %s" format msg.body)
   }
 
   final override def preRestart(reason: Throwable, message: Option[Any]) {
     super.preRestart(reason, message)
-    sender ! Failure(reason)
+    sender() ! Failure(reason)
   }
 }
 

akka-camel/src/test/scala/akka/camel/ProducerFeatureTest.scala

@@ -60,7 +60,7 @@ class ProducerFeatureTest extends TestKit(ActorSystem("test", AkkaSpec.testConf)
           case p: Props ⇒ {
             val producer = context.actorOf(p)
             context.watch(producer)
-            sender ! producer
+            sender() ! producer
           }
           case Terminated(actorRef) ⇒ {
             deadActor = Some(actorRef)
@@ -275,7 +275,7 @@ object ProducerFeatureTest {
         body: String ⇒
           if (body == "err") throw new Exception("Crash!")
           val upperMsg = body.toUpperCase
-          lastSender = Some(sender)
+          lastSender = Some(sender())
           lastMessage = Some(upperMsg)
       }
       else msg
@@ -314,9 +314,9 @@ object ProducerFeatureTest {
   class TestResponder extends Actor {
     def receive = {
       case msg: CamelMessage ⇒ msg.body match {
-        case "fail" ⇒ context.sender ! akka.actor.Status.Failure(new AkkaCamelException(new Exception("failure"), msg.headers))
+        case "fail" ⇒ context.sender() ! akka.actor.Status.Failure(new AkkaCamelException(new Exception("failure"), msg.headers))
         case _ ⇒
-          context.sender ! (msg.mapBody {
+          context.sender() ! (msg.mapBody {
             body: String ⇒ "received %s" format body
           })
       }
@@ -326,10 +326,10 @@ object ProducerFeatureTest {
   class ReplyingForwardTarget extends Actor {
     def receive = {
       case msg: CamelMessage ⇒
-        context.sender ! (msg.copy(headers = msg.headers + ("test" -> "result")))
+        context.sender() ! (msg.copy(headers = msg.headers + ("test" -> "result")))
       case msg: akka.actor.Status.Failure ⇒
         msg.cause match {
-          case e: AkkaCamelException ⇒ context.sender ! Status.Failure(new AkkaCamelException(e, e.headers + ("test" -> "failure")))
+          case e: AkkaCamelException ⇒ context.sender() ! Status.Failure(new AkkaCamelException(e, e.headers + ("test" -> "failure")))
         }
     }
   }
@@ -368,8 +368,8 @@ object ProducerFeatureTest {
 
   class IntermittentErrorConsumer(override val endpointUri: String) extends Consumer {
     def receive = {
-      case msg: CamelMessage if msg.bodyAs[String] == "fail" ⇒ sender ! Failure(new Exception("fail"))
+      case msg: CamelMessage if msg.bodyAs[String] == "fail" ⇒ sender() ! Failure(new Exception("fail"))
-      case msg: CamelMessage                                 ⇒ sender ! msg
+      case msg: CamelMessage                                 ⇒ sender() ! msg
     }
   }
 

akka-camel/src/test/scala/akka/camel/internal/component/ActorProducerTest.scala

@@ -69,7 +69,7 @@ class ActorProducerTest extends TestKit(ActorSystem("test")) with WordSpecLike w
             within(1 second) {
               probe.expectMsgType[CamelMessage]
               info("message sent to consumer")
-              probe.sender ! Ack
+              probe.sender() ! Ack
             }
             verify(exchange, never()).setResponse(any[CamelMessage])
             info("no response forwarded to exchange")
@@ -173,7 +173,7 @@ class ActorProducerTest extends TestKit(ActorSystem("test")) with WordSpecLike w
 
             within(1 second) {
               probe.expectMsgType[CamelMessage]
-              probe.sender ! "some message"
+              probe.sender() ! "some message"
             }
             doneSync should be(false)
             info("done async")
@@ -196,7 +196,7 @@ class ActorProducerTest extends TestKit(ActorSystem("test")) with WordSpecLike w
 
             within(1 second) {
               probe.expectMsgType[CamelMessage]
-              probe.sender ! failure
+              probe.sender() ! failure
               asyncCallback.awaitCalled(remaining)
             }
 
@@ -259,7 +259,7 @@ class ActorProducerTest extends TestKit(ActorSystem("test")) with WordSpecLike w
               within(1 second) {
                 probe.expectMsgType[CamelMessage]
                 info("message sent to consumer")
-                probe.sender ! Ack
+                probe.sender() ! Ack
                 asyncCallback.expectDoneAsyncWithin(remaining)
                 info("async callback called")
               }
@@ -277,7 +277,7 @@ class ActorProducerTest extends TestKit(ActorSystem("test")) with WordSpecLike w
               within(1 second) {
                 probe.expectMsgType[CamelMessage]
                 info("message sent to consumer")
-                probe.sender ! "some neither Ack nor Failure response"
+                probe.sender() ! "some neither Ack nor Failure response"
                 asyncCallback.expectDoneAsyncWithin(remaining)
                 info("async callback called")
               }
@@ -310,7 +310,7 @@ class ActorProducerTest extends TestKit(ActorSystem("test")) with WordSpecLike w
               within(1 second) {
                 probe.expectMsgType[CamelMessage]
                 info("message sent to consumer")
-                probe.sender ! Failure(new Exception)
+                probe.sender() ! Failure(new Exception)
                 asyncCallback.awaitCalled(remaining)
               }
               verify(exchange, never()).setResponse(any[CamelMessage])
@@ -427,7 +427,7 @@ private[camel] trait ActorProducerFixture extends MockitoSugar with BeforeAndAft
   }
 
   def echoActor = system.actorOf(Props(new Actor {
-    def receive = { case msg ⇒ sender ! "received " + msg }
+    def receive = { case msg ⇒ sender() ! "received " + msg }
   }), name = "echoActor")
 
 }

akka-cluster/src/main/scala/akka/cluster/ClusterDaemon.scala

@@ -206,7 +206,7 @@ private[cluster] final class ClusterCoreSupervisor extends Actor with ActorLoggi
   override def postStop(): Unit = Cluster(context.system).shutdown()
 
   def receive = {
-    case InternalClusterAction.GetClusterCoreRef ⇒ sender ! coreDaemon
+    case InternalClusterAction.GetClusterCoreRef ⇒ sender() ! coreDaemon
   }
 }
 
@@ -289,7 +289,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
   }
 
   def uninitialized: Actor.Receive = {
-    case InitJoin                          ⇒ sender ! InitJoinNack(selfAddress)
+    case InitJoin                          ⇒ sender() ! InitJoinNack(selfAddress)
     case ClusterUserAction.JoinTo(address) ⇒ join(address)
     case JoinSeedNodes(seedNodes)          ⇒ joinSeedNodes(seedNodes)
     case msg: SubscriptionMessage          ⇒ publisher forward msg
@@ -297,7 +297,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
 
   def tryingToJoin(joinWith: Address, deadline: Option[Deadline]): Actor.Receive = {
     case Welcome(from, gossip) ⇒ welcome(joinWith, from, gossip)
-    case InitJoin              ⇒ sender ! InitJoinNack(selfAddress)
+    case InitJoin              ⇒ sender() ! InitJoinNack(selfAddress)
     case ClusterUserAction.JoinTo(address) ⇒
       becomeUninitialized()
       join(address)
@@ -364,7 +364,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
     case other             ⇒ super.unhandled(other)
   }
 
-  def initJoin(): Unit = sender ! InitJoinAck(selfAddress)
+  def initJoin(): Unit = sender() ! InitJoinAck(selfAddress)
 
   def joinSeedNodes(seedNodes: immutable.IndexedSeq[Address]): Unit = {
     if (seedNodes.nonEmpty) {
@@ -464,7 +464,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
 
         logInfo("Node [{}] is JOINING, roles [{}]", node.address, roles.mkString(", "))
         if (node != selfUniqueAddress) {
-          sender ! Welcome(selfUniqueAddress, latestGossip)
+          sender() ! Welcome(selfUniqueAddress, latestGossip)
         }
 
         publish(latestGossip)
@@ -484,7 +484,7 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
       latestGossip = gossip seen selfUniqueAddress
       publish(latestGossip)
       if (from != selfUniqueAddress)
-        gossipTo(from, sender)
+        gossipTo(from, sender())
       becomeInitialized()
     }
   }
@@ -574,8 +574,8 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
     else {
       (status.version compareTo latestGossip.version) match {
         case VectorClock.Same  ⇒ // same version
-        case VectorClock.After ⇒ gossipStatusTo(from, sender) // remote is newer
+        case VectorClock.After ⇒ gossipStatusTo(from, sender()) // remote is newer
-        case _                 ⇒ gossipTo(from, sender) // conflicting or local is newer
+        case _                 ⇒ gossipTo(from, sender()) // conflicting or local is newer
       }
     }
   }
@@ -664,9 +664,9 @@ private[cluster] class ClusterCoreDaemon(publisher: ActorRef) extends Actor with
       if (selfStatus == Exiting || selfStatus == Down)
         shutdown()
       else if (talkback) {
-        // send back gossip to sender when sender had different view, i.e. merge, or sender had
+        // send back gossip to sender() when sender() had different view, i.e. merge, or sender() had
-        // older or sender had newer
+        // older or sender() had newer
-        gossipTo(from, sender)
+        gossipTo(from, sender())
       }
       gossipType
     }

akka-cluster/src/main/scala/akka/cluster/ClusterHeartbeat.scala

@@ -22,7 +22,7 @@ private[cluster] final class ClusterHeartbeatReceiver extends Actor with ActorLo
   val selfHeartbeatRsp = HeartbeatRsp(Cluster(context.system).selfUniqueAddress)
 
   def receive = {
-    case Heartbeat(from) ⇒ sender ! selfHeartbeatRsp
+    case Heartbeat(from) ⇒ sender() ! selfHeartbeatRsp
   }
 
 }

akka-cluster/src/main/scala/akka/cluster/routing/AdaptiveLoadBalancing.scala

@@ -47,7 +47,7 @@ final case class AdaptiveLoadBalancingRoutingLogic(system: ActorSystem, metricsS
 
   // The current weighted routees, if any. Weights are produced by the metricsSelector
   // via the metricsListener Actor. It's only updated by the actor, but accessed from
-  // the threads of the senders.
+  // the threads of the sender()s.
   private val weightedRouteesRef =
     new AtomicReference[(immutable.IndexedSeq[Routee], Set[NodeMetrics], Option[WeightedRoutees])](
       (Vector.empty, Set.empty, None))

akka-cluster/src/multi-jvm/scala/akka/cluster/MultiNodeClusterSpec.scala

@@ -68,7 +68,7 @@ object MultiNodeClusterSpec {
         }
       case End ⇒
         testActor forward End
-        sender ! EndAck
+        sender() ! EndAck
       case EndAck ⇒
         testActor forward EndAck
     }

akka-cluster/src/multi-jvm/scala/akka/cluster/RestartFirstSeedNodeSpec.scala

@@ -70,7 +70,7 @@ abstract class RestartFirstSeedNodeSpec
           def receive = {
             case a: Address ⇒
               seedNode1Address = a
-              sender ! "ok"
+              sender() ! "ok"
           }
         }).withDeploy(Deploy.local), name = "address-receiver")
         enterBarrier("seed1-address-receiver-ready")

akka-cluster/src/multi-jvm/scala/akka/cluster/StressSpec.scala

@@ -520,8 +520,8 @@ private[cluster] object StressMultiJvmSpec extends MultiNodeConfig {
       case SendBatch ⇒ sendJobs()
       case RetryTick ⇒ resend()
       case End ⇒
-        done(sender)
+        done(sender())
-        context.become(ending(sender))
+        context.become(ending(sender()))
     }
 
     def ending(replyTo: ActorRef): Receive = {
@@ -571,7 +571,7 @@ private[cluster] object StressMultiJvmSpec extends MultiNodeConfig {
    */
   class Worker extends Actor with ActorLogging {
     def receive = {
-      case SimpleJob(id, payload) ⇒ sender ! Ack(id)
+      case SimpleJob(id, payload) ⇒ sender() ! Ack(id)
       case TreeJob(id, payload, idx, levels, width) ⇒
         // create the actors when first TreeJob message is received
         val totalActors = ((width * math.pow(width, levels) - 1) / (width - 1)).toInt
@@ -583,7 +583,7 @@ private[cluster] object StressMultiJvmSpec extends MultiNodeConfig {
     }
 
     def treeWorker(tree: ActorRef): Receive = {
-      case SimpleJob(id, payload) ⇒ sender ! Ack(id)
+      case SimpleJob(id, payload) ⇒ sender() ! Ack(id)
       case TreeJob(id, payload, idx, _, _) ⇒
         tree forward ((idx, SimpleJob(id, payload)))
     }
@@ -602,7 +602,7 @@ private[cluster] object StressMultiJvmSpec extends MultiNodeConfig {
 
   class Leaf extends Actor {
     def receive = {
-      case (_: Int, job: SimpleJob) ⇒ sender ! Ack(job.id)
+      case (_: Int, job: SimpleJob) ⇒ sender() ! Ack(job.id)
     }
   }
 
@@ -630,7 +630,7 @@ private[cluster] object StressMultiJvmSpec extends MultiNodeConfig {
     def receive = {
       case props: Props     ⇒ context.actorOf(props)
       case e: Exception     ⇒ context.children foreach { _ ! e }
-      case GetChildrenCount ⇒ sender ! ChildrenCount(context.children.size, restartCount)
+      case GetChildrenCount ⇒ sender() ! ChildrenCount(context.children.size, restartCount)
       case Reset ⇒
         require(context.children.isEmpty,
           s"ResetChildrenCount not allowed when children exists, [${context.children.size}]")

akka-cluster/src/multi-jvm/scala/akka/cluster/SurviveNetworkInstabilitySpec.scala

@@ -43,7 +43,7 @@ object SurviveNetworkInstabilityMultiJvmSpec extends MultiNodeConfig {
 
   class Parent extends Actor {
     def receive = {
-      case p: Props ⇒ sender ! context.actorOf(p)
+      case p: Props ⇒ sender() ! context.actorOf(p)
     }
   }
 
@@ -53,7 +53,7 @@ object SurviveNetworkInstabilityMultiJvmSpec extends MultiNodeConfig {
     def receive = {
       case "hello" ⇒
         context.system.scheduler.scheduleOnce(2.seconds, self, "boom")
-        sender ! "hello"
+        sender() ! "hello"
       case "boom" ⇒ throw new SimulatedException
     }
   }

akka-cluster/src/multi-jvm/scala/akka/cluster/oldrouting/AdaptiveLoadBalancingRouterSpec.scala

@@ -27,7 +27,7 @@ object AdaptiveLoadBalancingRouterMultiJvmSpec extends MultiNodeConfig {
 
   class Routee extends Actor {
     def receive = {
-      case _ ⇒ sender ! Reply(Cluster(context.system).selfAddress)
+      case _ ⇒ sender() ! Reply(Cluster(context.system).selfAddress)
     }
   }
 
@@ -45,7 +45,7 @@ object AdaptiveLoadBalancingRouterMultiJvmSpec extends MultiNodeConfig {
         val numberOfArrays = allocateBytes / 1024
         usedMemory = Array.ofDim(numberOfArrays, 248) // each 248 element Int array will use ~ 1 kB
         log.debug("used heap after: [{}] bytes", ManagementFactory.getMemoryMXBean.getHeapMemoryUsage.getUsed)
-        sender ! "done"
+        sender() ! "done"
     }
   }
 

akka-cluster/src/multi-jvm/scala/akka/cluster/oldrouting/ClusterConsistentHashingRouterSpec.scala

@@ -29,7 +29,7 @@ object ClusterConsistentHashingRouterMultiJvmSpec extends MultiNodeConfig {
 
   class Echo extends Actor {
     def receive = {
-      case _ ⇒ sender ! self
+      case _ ⇒ sender() ! self
     }
   }
 

akka-cluster/src/multi-jvm/scala/akka/cluster/oldrouting/ClusterRoundRobinRoutedActorSpec.scala

@@ -30,7 +30,7 @@ object ClusterRoundRobinRoutedActorMultiJvmSpec extends MultiNodeConfig {
     def this() = this(DeployRoutee)
 
     def receive = {
-      case "hit" ⇒ sender ! Reply(routeeType, self)
+      case "hit" ⇒ sender() ! Reply(routeeType, self)
     }
   }