ExplicitResultTypes manually for implicit local val / def

ExplicitResultTypes scalafix rule can't fix those cases

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

@@ -355,7 +355,7 @@ class ActorSelectionSpec extends AkkaSpec with DefaultTimeout {
 
     "identify actors with wildcard selection correctly" in {
       val creator = TestProbe()
-      implicit def self = creator.ref
+      implicit def self: ActorRef = creator.ref
       val top = system.actorOf(p, "a")
       val b1 = Await.result((top ? Create("b1")).mapTo[ActorRef], timeout.duration)
       val b2 = Await.result((top ? Create("b2")).mapTo[ActorRef], timeout.duration)

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

@@ -263,7 +263,7 @@ class ActorSystemSpec extends AkkaSpec(ActorSystemSpec.config) with ImplicitSend
 
     "reliably create waves of actors" in {
       import system.dispatcher
-      implicit val timeout = Timeout((20 seconds).dilated)
+      implicit val timeout: Timeout = Timeout((20 seconds).dilated)
       val waves = for (_ <- 1 to 3) yield system.actorOf(Props[ActorSystemSpec.Waves]) ? 50000
       Await.result(Future.sequence(waves), timeout.duration + 5.seconds) should ===(Vector("done", "done", "done"))
     }

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

@@ -130,7 +130,7 @@ class LocalActorRefProviderSpec extends AkkaSpec(LocalActorRefProviderSpec.confi
 
       for (i <- 0 until 100) {
         val address = "new-actor" + i
-        implicit val timeout = Timeout(5 seconds)
+        implicit val timeout: Timeout = Timeout(5 seconds)
         val actors =
           for (_ <- 1 to 4)
             yield Future(system.actorOf(Props(new Actor { def receive = { case _ => } }), address))

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

@@ -496,7 +496,7 @@ class LightArrayRevolverSchedulerSpec extends AkkaSpec(SchedulerSpec.testConfRev
 
       "execute multiple jobs at once when expiring multiple buckets" taggedAs TimingTest in {
         withScheduler() { (sched, driver) =>
-          implicit def ec = localEC
+          implicit def ec: ExecutionContext = localEC
           import driver._
           val start = step / 2
           (0 to 3).foreach(i => sched.scheduleOnce(start + step * i, testActor, "hello"))
@@ -511,7 +511,7 @@ class LightArrayRevolverSchedulerSpec extends AkkaSpec(SchedulerSpec.testConfRev
 
       "properly defer jobs even when the timer thread oversleeps" taggedAs TimingTest in {
         withScheduler() { (sched, driver) =>
-          implicit def ec = localEC
+          implicit def ec: ExecutionContext = localEC
           import driver._
           sched.scheduleOnce(step * 3, probe.ref, "hello")
           wakeUp(step * 5)
@@ -526,7 +526,7 @@ class LightArrayRevolverSchedulerSpec extends AkkaSpec(SchedulerSpec.testConfRev
 
       "correctly wrap around wheel rounds" taggedAs TimingTest in {
         withScheduler(config = ConfigFactory.parseString("akka.scheduler.ticks-per-wheel=2")) { (sched, driver) =>
-          implicit def ec = localEC
+          implicit def ec: ExecutionContext = localEC
           import driver._
           val start = step / 2
           (0 to 3).foreach(i => sched.scheduleOnce(start + step * i, probe.ref, "hello"))
@@ -553,7 +553,7 @@ class LightArrayRevolverSchedulerSpec extends AkkaSpec(SchedulerSpec.testConfRev
 
       "correctly execute jobs when clock wraps around" taggedAs TimingTest in {
         withScheduler(Long.MaxValue - 200000000L) { (sched, driver) =>
-          implicit def ec = localEC
+          implicit def ec: ExecutionContext = localEC
           import driver._
           val start = step / 2
           (0 to 3).foreach(i => sched.scheduleOnce(start + step * i, testActor, "hello"))
@@ -583,7 +583,7 @@ class LightArrayRevolverSchedulerSpec extends AkkaSpec(SchedulerSpec.testConfRev
         val targetTicks = Int.MaxValue - numEvents + 20
 
         withScheduler(_startTick = Int.MaxValue - 100) { (sched, driver) =>
-          implicit def ec = localEC
+          implicit def ec: ExecutionContext = localEC
           import driver._
 
           val start = step / 2

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

@@ -7,6 +7,7 @@ package akka.dataflow
 import language.postfixOps
 
 import akka.actor.{ Actor, Props }
+import akka.actor.ActorRef
 import scala.concurrent.Future
 import scala.concurrent.Await
 import scala.concurrent.duration._
@@ -25,7 +26,7 @@ class Future2ActorSpec extends AkkaSpec with DefaultTimeout {
     }
 
     "support convenient sending to multiple destinations with implicit sender" in {
-      implicit val someActor = system.actorOf(Props(new Actor { def receive = Actor.emptyBehavior }))
+      implicit val someActor: ActorRef = system.actorOf(Props(new Actor { def receive = Actor.emptyBehavior }))
       Future(42).pipeTo(testActor).pipeTo(testActor)
       expectMsgAllOf(1 second, 42, 42)
       lastSender should ===(someActor)

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

@@ -19,7 +19,7 @@ class AskSpec extends AkkaSpec {
 
   "The “ask” pattern" must {
     "send request to actor and wrap the answer in Future" in {
-      implicit val timeout = Timeout(5.seconds)
+      implicit val timeout: Timeout = Timeout(5.seconds)
       val echo = system.actorOf(Props(new Actor { def receive = { case x => sender() ! x } }))
       val f = echo ? "ping"
       f.futureValue should ===("ping")
@@ -35,7 +35,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "return broken promises on EmptyLocalActorRefs" in {
-      implicit val timeout = Timeout(5 seconds)
+      implicit val timeout: Timeout = Timeout(5 seconds)
       val empty = system.asInstanceOf[ExtendedActorSystem].provider.resolveActorRef("/user/unknown")
       val f = empty ? 3.14
       f.isCompleted should ===(true)
@@ -46,7 +46,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "return broken promises on unsupported ActorRefs" in {
-      implicit val timeout = Timeout(5 seconds)
+      implicit val timeout: Timeout = Timeout(5 seconds)
       val f = ask(null: ActorRef, 3.14)
       f.isCompleted should ===(true)
 
@@ -57,7 +57,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "return broken promises on 0 timeout" in {
-      implicit val timeout = Timeout(0 seconds)
+      implicit val timeout: Timeout = Timeout(0 seconds)
       val echo = system.actorOf(Props(new Actor { def receive = { case x => sender() ! x } }))
       val f = echo ? "foo"
       val expectedMsg =
@@ -68,7 +68,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "return broken promises on < 0 timeout" in {
-      implicit val timeout = Timeout(-1000 seconds)
+      implicit val timeout: Timeout = Timeout(-1000 seconds)
       val echo = system.actorOf(Props(new Actor { def receive = { case x => sender() ! x } }))
       val f = echo ? "foo"
       val expectedMsg =
@@ -79,7 +79,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "include target information in AskTimeout" in {
-      implicit val timeout = Timeout(0.5 seconds)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
       val silentOne = system.actorOf(Props.empty, "silent")
       val f = silentOne ? "noreply"
       intercept[AskTimeoutException] {
@@ -88,7 +88,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "include timeout information in AskTimeout" in {
-      implicit val timeout = Timeout(0.5 seconds)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
       val f = system.actorOf(Props.empty) ? "noreply"
       intercept[AskTimeoutException] {
         Await.result(f, 1 second)
@@ -96,8 +96,8 @@ class AskSpec extends AkkaSpec {
     }
 
     "include sender information in AskTimeout" in {
-      implicit val timeout = Timeout(0.5 seconds)
-      implicit val sender = system.actorOf(Props.empty)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
+      implicit val sender: ActorRef = system.actorOf(Props.empty)
       val f = system.actorOf(Props.empty) ? "noreply"
       intercept[AskTimeoutException] {
         Await.result(f, 1 second)
@@ -105,7 +105,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "include message class information in AskTimeout" in {
-      implicit val timeout = Timeout(0.5 seconds)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
       val f = system.actorOf(Props.empty) ? Integer.valueOf(17)
       intercept[AskTimeoutException] {
         Await.result(f, 1 second)
@@ -113,7 +113,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "work for ActorSelection" in {
-      implicit val timeout = Timeout(5 seconds)
+      implicit val timeout: Timeout = Timeout(5 seconds)
       import system.dispatcher
       val echo = system.actorOf(Props(new Actor { def receive = { case x => sender() ! x } }), "select-echo")
       val identityFuture =
@@ -123,7 +123,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "work when reply uses actor selection" in {
-      implicit val timeout = Timeout(5 seconds)
+      implicit val timeout: Timeout = Timeout(5 seconds)
       val deadListener = TestProbe()
       system.eventStream.subscribe(deadListener.ref, classOf[DeadLetter])
 
@@ -138,7 +138,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "throw AskTimeoutException on using *" in {
-      implicit val timeout = Timeout(0.5 seconds)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
       val deadListener = TestProbe()
       system.eventStream.subscribe(deadListener.ref, classOf[DeadLetter])
 
@@ -154,7 +154,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "throw AskTimeoutException on using .." in {
-      implicit val timeout = Timeout(0.5 seconds)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
       val deadListener = TestProbe()
       system.eventStream.subscribe(deadListener.ref, classOf[DeadLetter])
 
@@ -175,7 +175,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "send to DeadLetter when child does not exist" in {
-      implicit val timeout = Timeout(0.5 seconds)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
       val deadListener = TestProbe()
       system.eventStream.subscribe(deadListener.ref, classOf[DeadLetter])
 
@@ -194,7 +194,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "send DeadLetter when answering to grandchild" in {
-      implicit val timeout = Timeout(0.5 seconds)
+      implicit val timeout: Timeout = Timeout(0.5 seconds)
       val deadListener = TestProbe()
       system.eventStream.subscribe(deadListener.ref, classOf[DeadLetter])
 
@@ -212,7 +212,7 @@ class AskSpec extends AkkaSpec {
     }
 
     "allow watching the promiseActor and send Terminated() when completes" in {
-      implicit val timeout = Timeout(300 millis)
+      implicit val timeout: Timeout = Timeout(300 millis)
       val p = TestProbe()
 
       val act = system.actorOf(Props(new Actor {

akka-actor-tests/src/test/scala/akka/pattern/extended/ExplicitAskSpec.scala

@@ -19,7 +19,7 @@ class ExplicitAskSpec extends AkkaSpec {
 
   "The “ask” pattern with explicit sender" must {
     "allow to access an explicit reference to actor to respond to" in {
-      implicit val timeout = Timeout(5.seconds)
+      implicit val timeout: Timeout = Timeout(5.seconds)
 
       val target = system.actorOf(Props(new Actor {
         def receive = {
@@ -32,7 +32,7 @@ class ExplicitAskSpec extends AkkaSpec {
     }
 
     "work for ActorSelection" in {
-      implicit val timeout = Timeout(5.seconds)
+      implicit val timeout: Timeout = Timeout(5.seconds)
 
       val target = system.actorOf(Props(new Actor {
         def receive = {

akka-actor-typed-tests/src/test/scala/akka/actor/typed/SpawnProtocolSpec.scala

@@ -48,7 +48,7 @@ class SpawnProtocolSpec extends ScalaTestWithActorTestKit with AnyWordSpecLike w
     "have nice API for ask" in {
       val parent = spawn(SpawnProtocol(), "parent2")
       import akka.actor.typed.scaladsl.AskPattern._
-      implicit val timeout = Timeout(5.seconds)
+      implicit val timeout: Timeout = Timeout(5.seconds)
       val parentReply: Future[ActorRef[Ping]] =
         parent.ask(SpawnProtocol.Spawn(target, "child", Props.empty, _))
       val child = parentReply.futureValue

akka-actor-typed-tests/src/test/scala/docs/akka/typed/StyleGuideDocExamples.scala

@@ -428,7 +428,7 @@ object StyleGuideDocExamples {
     import akka.actor.typed.scaladsl.AskPattern._
     import akka.util.Timeout
 
-    implicit val timeout = Timeout(3.seconds)
+    implicit val timeout: Timeout = Timeout(3.seconds)
     val counter: ActorRef[Command] = ???
 
     val result: Future[OperationResult] = counter.ask(replyTo => Increment(delta = 2, replyTo))

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

@@ -22,6 +22,7 @@ import scala.collection.immutable
 import scala.concurrent.Await
 import scala.language.existentials
 import scala.util.control.{ NoStackTrace, NonFatal }
+import akka.util.Timeout
 
 /**
  * This trait brings log level handling to the EventStream: it reads the log
@@ -198,7 +199,7 @@ trait LoggingBus extends ActorEventBus {
       logName: String): ActorRef = {
     val name = "log" + LogExt(system).id() + "-" + simpleName(clazz)
     val actor = system.systemActorOf(Props(clazz).withDispatcher(system.settings.LoggersDispatcher), name)
-    implicit def timeout = system.settings.LoggerStartTimeout
+    implicit def timeout: Timeout = system.settings.LoggerStartTimeout
     import akka.pattern.ask
     val response = try Await.result(actor ? InitializeLogger(this), timeout.duration)
     catch {

project/AkkaBuild.scala

@@ -142,7 +142,7 @@ object AkkaBuild {
          |implicit def _system = system
          |def startSystem(remoting: Boolean = false) { system = ActorSystem("repl", if(remoting) remoteConfig else config); println("don’t forget to system.terminate()!") }
          |implicit def ec = system.dispatcher
-         |implicit val timeout = Timeout(5 seconds)
+         |implicit val timeout: Timeout = Timeout(5 seconds)
          |""".stripMargin,
 
     /**