Remove some of Unused import warning (#24750)

* Remove `Unused import` of `akka-actor-typed`

* Remove `Unused import` of `akka-actor-typed-tests`

* Remove `Unused import` of `akka-stream-tests`

* Remove `Unused import` of `akka-persistence`

* Remove `Unused import` of `akka-persistence-typed`

* Remove `Unused import` of `akka-cluster-typed`

* Remove `Unused import` of `akka-cluster-sharding-typed`

* Format source code

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

@@ -13,7 +13,6 @@ import scala.util.control.NoStackTrace
 import akka.actor.typed.scaladsl.Behaviors
 import akka.actor.typed.scaladsl.TimerScheduler
 import akka.testkit.TimingTest
-import akka.testkit.typed.TestKitSettings
 import akka.testkit.typed.scaladsl.{ ActorTestKit, _ }
 import org.scalatest.WordSpecLike
 

akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorLoggingSpec.scala

@@ -4,7 +4,7 @@
 
 package akka.actor.typed.scaladsl
 
-import akka.actor.typed.{ LogMarker, TestException, TypedAkkaSpec, scaladsl }
+import akka.actor.typed.{ LogMarker, TestException, TypedAkkaSpec }
 import akka.testkit.EventFilter
 import com.typesafe.config.ConfigFactory
 import akka.actor.typed.scaladsl.adapter._
@@ -12,8 +12,6 @@ import akka.event.Logging
 import akka.event.Logging.{ LogEventWithCause, LogEventWithMarker }
 import akka.testkit.typed.scaladsl.ActorTestKit
 
-import scala.util.control.NoStackTrace
-
 class ActorLoggingSpec extends ActorTestKit with TypedAkkaSpec {
 
   override def config = ConfigFactory.parseString(

akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala

@@ -4,11 +4,6 @@
 
 package akka.actor.typed.scaladsl
 
-import scala.concurrent.TimeoutException
-import scala.concurrent.duration._
-import scala.reflect.ClassTag
-import scala.util.Failure
-import scala.util.Success
 import akka.actor.typed.scaladsl.adapter._
 import akka.actor.typed.ActorRef
 import akka.actor.typed.PostStop

akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/adapter/AdapterSpec.scala

@@ -7,14 +7,12 @@ package akka.actor.typed.scaladsl.adapter
 import scala.concurrent.duration._
 import scala.util.control.NoStackTrace
 import akka.actor.typed.{ ActorRef, ActorSystem, Behavior, Terminated }
-import akka.actor.{ InvalidMessageException, Props }
+import akka.actor.InvalidMessageException
 import akka.actor.typed.scaladsl.Behaviors
 import akka.{ Done, NotUsed, actor ⇒ untyped }
 import akka.testkit._
 import akka.actor.typed.Behavior.UntypedPropsBehavior
 
-import scala.concurrent.Await
-
 object AdapterSpec {
   val untyped1: untyped.Props = untyped.Props(new Untyped1)
 

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

@@ -8,7 +8,7 @@ import java.net.URI
 
 import akka.NotUsed
 import akka.actor.typed.{ ActorRef, ActorSystem, Behavior, TypedAkkaSpecWithShutdown }
-import akka.actor.typed.scaladsl.{ ActorContext, Behaviors, TimerScheduler }
+import akka.actor.typed.scaladsl.{ Behaviors, TimerScheduler }
 import akka.testkit.typed.scaladsl.{ ActorTestKit, TestProbe }
 import akka.util.Timeout
 

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

@@ -8,7 +8,6 @@ import akka.annotation.InternalApi
 import akka.{ actor ⇒ a }
 
 import scala.annotation.unchecked.uncheckedVariance
-import language.implicitConversions
 import scala.concurrent.Future
 import scala.util.Success
 

akka-actor-typed/src/main/scala/akka/actor/typed/Behavior.scala

@@ -8,12 +8,10 @@ import akka.actor.InvalidMessageException
 import akka.actor.typed.internal.BehaviorImpl
 
 import scala.annotation.tailrec
-import akka.util.{ ConstantFun, LineNumbers, OptionVal }
+import akka.util.{ LineNumbers, OptionVal }
 import akka.annotation.{ DoNotInherit, InternalApi }
 import akka.actor.typed.scaladsl.{ ActorContext ⇒ SAC }
 
-import scala.reflect.ClassTag
-
 /**
  * The behavior of an actor defines how it reacts to the messages that it
  * receives. The message may either be of the type that the Actor declares

akka-actor-typed/src/main/scala/akka/actor/typed/internal/Restarter.scala

@@ -11,7 +11,6 @@ import akka.actor.DeadLetterSuppression
 import akka.actor.typed.SupervisorStrategy._
 import akka.actor.typed.scaladsl.Behaviors
 import akka.annotation.InternalApi
-import akka.event.Logging
 import akka.util.OptionVal
 
 import scala.concurrent.duration.{ Deadline, FiniteDuration }

akka-actor-typed/src/main/scala/akka/actor/typed/internal/TimerSchedulerImpl.scala

@@ -8,11 +8,8 @@ package internal
 import scala.concurrent.duration.FiniteDuration
 
 import akka.actor.Cancellable
-import akka.annotation.ApiMayChange
-import akka.annotation.DoNotInherit
 import akka.annotation.InternalApi
 import akka.dispatch.ExecutionContexts
-import akka.actor.typed.ActorRef
 import akka.actor.typed.ActorRef.ActorRefOps
 import akka.actor.typed.javadsl
 import akka.actor.typed.scaladsl

akka-actor-typed/src/main/scala/akka/actor/typed/internal/adapter/ActorAdapter.scala

@@ -18,7 +18,6 @@ import scala.util.control.NonFatal
  */
 @InternalApi private[typed] class ActorAdapter[T](_initialBehavior: Behavior[T]) extends a.Actor with a.ActorLogging {
   import Behavior._
-  import ActorRefAdapter.toUntyped
 
   protected var behavior: Behavior[T] = _initialBehavior
 

akka-actor-typed/src/main/scala/akka/actor/typed/internal/adapter/ActorContextAdapter.scala

@@ -82,7 +82,6 @@ import scala.concurrent.duration._
     actorLogger match {
       case OptionVal.Some(logger) ⇒ logger
       case OptionVal.None ⇒
-        import scala.language.existentials
         val logSource = self.path.toString
         val logClass = classOf[Behavior[_]] // FIXME figure out a better class somehow
         val system = untyped.system.asInstanceOf[ExtendedActorSystem]

akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/Adapter.scala

@@ -8,7 +8,6 @@ import akka.actor.typed.Behavior
 import akka.actor.typed.Props
 import akka.actor.typed.EmptyProps
 import akka.actor.typed.ActorRef
-import akka.actor.typed.internal.adapter.ActorRefAdapter
 import akka.actor.typed.scaladsl.adapter._
 import akka.actor.typed.ActorSystem
 import akka.actor.typed.internal.adapter.ActorContextAdapter

akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala

@@ -140,8 +140,6 @@ class BehaviorBuilder[T] private (
 object BehaviorBuilder {
   def create[T]: BehaviorBuilder[T] = new BehaviorBuilder[T](Nil, Nil)
 
-  import scala.language.existentials
-
   /** INTERNAL API */
   @InternalApi
   private[javadsl] final case class Case[BT, MT](`type`: Class[_ <: MT], test: Option[MT ⇒ Boolean], handler: (ActorContext[BT], MT) ⇒ Behavior[BT])

akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/ReceiveBuilder.scala

@@ -137,8 +137,6 @@ class ReceiveBuilder[T] private (
 object ReceiveBuilder {
   def create[T]: ReceiveBuilder[T] = new ReceiveBuilder[T](Nil, Nil)
 
-  import scala.language.existentials
-
   /** INTERNAL API */
   @InternalApi
   private[javadsl] final case class Case[BT, MT](`type`: Class[_ <: MT], test: Option[MT ⇒ Boolean], handler: MT ⇒ Behavior[BT])

akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/ActorContext.scala

@@ -6,7 +6,6 @@ package akka.actor.typed.scaladsl
 
 import akka.actor.typed._
 import akka.annotation.{ ApiMayChange, DoNotInherit }
-import akka.event.LoggingAdapter
 import akka.util.Timeout
 
 import scala.concurrent.ExecutionContextExecutor

akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/Behaviors.scala

@@ -5,6 +5,7 @@
 package akka.actor.typed
 package scaladsl
 
+import akka.annotation.ApiMayChange
 import akka.actor.typed.internal.{ BehaviorImpl, LoggingBehaviorImpl, Supervisor, TimerSchedulerImpl }
 import akka.annotation.{ ApiMayChange, DoNotInherit, InternalApi }
 

akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/StashBuffer.scala

@@ -4,8 +4,6 @@
 
 package akka.actor.typed.scaladsl
 
-import java.util.function.{ Function ⇒ JFunction }
-
 import akka.actor.typed.Behavior
 import akka.actor.typed.internal.StashBufferImpl
 import akka.annotation.DoNotInherit

akka-actor-typed/src/main/scala/akka/actor/typed/scaladsl/adapter/PropsAdapter.scala

@@ -5,9 +5,7 @@
 package akka.actor.typed.scaladsl.adapter
 
 import akka.actor.typed.Behavior
-import akka.actor.typed.EmptyProps
 import akka.actor.typed.Props
-import akka.actor.typed.internal.adapter.ActorAdapter
 
 /**
  * Wrap [[akka.actor.typed.Behavior]] in an untyped [[akka.actor.Props]], i.e. when

akka-cluster-sharding-typed/src/main/scala/akka/cluster/sharding/typed/javadsl/ClusterSharding.scala

@@ -15,7 +15,6 @@ import akka.actor.typed.Behavior
 import akka.actor.typed.Props
 import akka.annotation.DoNotInherit
 import akka.annotation.InternalApi
-import akka.cluster.sharding.ShardCoordinator.LeastShardAllocationStrategy
 import akka.cluster.sharding.ShardCoordinator.ShardAllocationStrategy
 import akka.cluster.sharding.typed.internal.EntityTypeKeyImpl
 import akka.japi.function.{ Function ⇒ JFunction }

akka-cluster-sharding-typed/src/main/scala/akka/cluster/sharding/typed/scaladsl/ClusterSharding.scala

@@ -20,7 +20,6 @@ import akka.actor.typed.ExtensionId
 import akka.actor.typed.Props
 import akka.annotation.DoNotInherit
 import akka.annotation.InternalApi
-import akka.cluster.sharding.ShardCoordinator.LeastShardAllocationStrategy
 import akka.cluster.sharding.ShardCoordinator.ShardAllocationStrategy
 import akka.cluster.sharding.typed.internal.ClusterShardingImpl
 import akka.cluster.sharding.typed.internal.EntityTypeKeyImpl

akka-cluster-sharding-typed/src/test/scala/akka/cluster/sharding/typed/scaladsl/ClusterShardingPersistenceSpec.scala

@@ -42,8 +42,6 @@ object ClusterShardingPersistenceSpec {
   final case class Get(replyTo: ActorRef[String]) extends Command
   final case object StopPlz extends Command
 
-  import PersistentBehaviors._
-
   def persistentActor(entityId: String): Behavior[Command] =
     PersistentBehaviors.receive[Command, String, String](
       entityId,

akka-cluster-typed/src/main/scala/akka/cluster/ddata/typed/internal/ReplicatorBehavior.scala

@@ -7,7 +7,6 @@ package akka.cluster.ddata.typed.internal
 import scala.compat.java8.OptionConverters._
 import scala.concurrent.duration._
 import scala.concurrent.duration.Duration
-import scala.concurrent.Future
 
 import akka.annotation.InternalApi
 import akka.cluster.{ ddata ⇒ dd }
@@ -18,7 +17,6 @@ import akka.actor.typed.scaladsl.Behaviors
 import akka.actor.typed.scaladsl.adapter._
 import akka.util.Timeout
 import akka.cluster.ddata.ReplicatedData
-import akka.cluster.ddata.Key
 import akka.actor.typed.Terminated
 
 /**

akka-cluster-typed/src/main/scala/akka/cluster/ddata/typed/javadsl/Replicator.scala

@@ -6,13 +6,11 @@ package akka.cluster.ddata.typed.javadsl
 
 import java.util.function.{ Function ⇒ JFunction }
 import akka.cluster.{ ddata ⇒ dd }
-import akka.cluster.ddata.typed.scaladsl
 import akka.cluster.ddata.Key
 import akka.cluster.ddata.ReplicatedData
 import akka.actor.typed.ActorRef
 import akka.actor.typed.Behavior
 import akka.cluster.ddata.typed.internal.ReplicatorBehavior
-import akka.cluster.ddata.typed.scaladsl
 
 import scala.concurrent.duration.FiniteDuration
 import scala.concurrent.duration.Duration
@@ -23,7 +21,6 @@ import akka.actor.{ DeadLetterSuppression, NoSerializationVerificationNeeded }
 import akka.actor.typed.{ ActorRef, Behavior }
 import akka.annotation.{ DoNotInherit, InternalApi }
 import akka.cluster.ddata.typed.internal.ReplicatorBehavior
-import akka.cluster.ddata.typed.scaladsl
 import akka.cluster.{ ddata ⇒ dd }
 
 import scala.concurrent.duration.{ Duration, FiniteDuration }

akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/AdaptedClusterSingletonImpl.scala

@@ -13,7 +13,6 @@ import akka.cluster.singleton.{ ClusterSingletonProxy, ClusterSingletonManager
 import akka.actor.typed.Behavior.UntypedPropsBehavior
 import akka.cluster.typed.{ Cluster, ClusterSingleton, ClusterSingletonImpl, ClusterSingletonSettings }
 import akka.actor.typed.internal.adapter.ActorSystemAdapter
-import akka.actor.typed.scaladsl.adapter._
 import akka.actor.typed.{ ActorRef, ActorSystem, Behavior, Props }
 
 /**

akka-cluster-typed/src/main/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionist.scala

@@ -16,7 +16,7 @@ import akka.cluster.ddata.{ DistributedData, ORMultiMap, ORMultiMapKey, Replicat
 import akka.cluster.{ Cluster, ClusterEvent }
 import akka.util.TypedMultiMap
 
-import scala.language.{ existentials, higherKinds }
+import scala.language.existentials
 import akka.actor.typed.scaladsl.adapter._
 
 /** INTERNAL API */

akka-cluster-typed/src/test/scala/akka/cluster/typed/RemoteContextAskSpec.scala

@@ -16,7 +16,6 @@ import akka.testkit.typed.scaladsl.{ ActorTestKit, TestProbe }
 import akka.actor.typed.scaladsl.adapter._
 import akka.util.Timeout
 import com.typesafe.config.ConfigFactory
-import org.scalatest.{ Matchers, WordSpecLike }
 
 import scala.concurrent.duration._
 import scala.util.{ Failure, Success }

akka-cluster-typed/src/test/scala/akka/cluster/typed/internal/receptionist/ClusterReceptionistSpec.scala

@@ -8,7 +8,6 @@ import java.nio.charset.StandardCharsets
 
 import akka.actor.ExtendedActorSystem
 import akka.actor.typed.{ ActorRef, ActorRefResolver, TypedAkkaSpecWithShutdown }
-import akka.actor.typed.internal.adapter.ActorSystemAdapter
 import akka.actor.typed.receptionist.{ Receptionist, ServiceKey }
 import akka.actor.typed.scaladsl.Behaviors
 import akka.actor.typed.scaladsl.adapter._
@@ -17,7 +16,6 @@ import akka.serialization.SerializerWithStringManifest
 import akka.testkit.typed.TestKitSettings
 import akka.testkit.typed.scaladsl.{ ActorTestKit, TestProbe }
 import com.typesafe.config.ConfigFactory
-import scala.concurrent.Await
 import scala.concurrent.duration._
 
 import akka.cluster.typed.Join

akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingEvents.scala

@@ -4,8 +4,8 @@
 
 package akka.persistence.typed.internal
 
-import akka.actor.typed.{ Behavior, PostStop, Signal }
+import akka.actor.typed.Behavior
-import akka.actor.typed.scaladsl.{ ActorContext, Behaviors, TimerScheduler }
+import akka.actor.typed.scaladsl.{ Behaviors, TimerScheduler }
 import akka.annotation.InternalApi
 import akka.event.Logging
 import akka.persistence.JournalProtocol._

akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedReplayingSnapshot.scala

@@ -5,8 +5,8 @@
 package akka.persistence.typed.internal
 
 import akka.actor.typed.scaladsl.Behaviors.same
-import akka.actor.typed.scaladsl.{ ActorContext, Behaviors, TimerScheduler }
+import akka.actor.typed.scaladsl.{ Behaviors, TimerScheduler }
-import akka.actor.typed.{ Behavior, PostStop, Signal }
+import akka.actor.typed.Behavior
 import akka.annotation.InternalApi
 import akka.persistence.SnapshotProtocol.{ LoadSnapshotFailed, LoadSnapshotResult }
 import akka.persistence._

akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRequestingRecoveryPermit.scala

@@ -4,10 +4,9 @@
 
 package akka.persistence.typed.internal
 
-import akka.actor.typed.{ Behavior, PostStop, PreRestart }
+import akka.actor.typed.Behavior
 import akka.actor.typed.scaladsl.Behaviors
 import akka.annotation.InternalApi
-import akka.persistence._
 import akka.persistence.typed.internal.EventsourcedBehavior.InternalProtocol
 
 /**

akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedRunning.scala

@@ -4,8 +4,7 @@
 
 package akka.persistence.typed.internal
 
-import akka.actor.typed.{ Behavior, Signal }
+import akka.actor.typed.Behavior
-import akka.actor.typed.Behavior.StoppedBehavior
 import akka.actor.typed.scaladsl.Behaviors
 import akka.actor.typed.scaladsl.MutableBehavior
 import akka.annotation.InternalApi

akka-persistence-typed/src/main/scala/akka/persistence/typed/internal/EventsourcedStashManagement.scala

@@ -6,11 +6,10 @@ package akka.persistence.typed.internal
 
 import akka.actor.typed.Behavior
 import akka.actor.typed.scaladsl.{ ActorContext, StashBuffer }
-import akka.actor.{ DeadLetter, ExtendedActorSystem, StashOverflowException }
+import akka.actor.{ DeadLetter, StashOverflowException }
 import akka.annotation.InternalApi
 import akka.persistence.typed.internal.EventsourcedBehavior.InternalProtocol
-import akka.persistence.{ StashOverflowStrategy, _ }
+import akka.persistence._
-import akka.util.Collections.EmptyImmutableSeq
 import akka.util.ConstantFun
 import akka.{ actor ⇒ a }
 

akka-persistence-typed/src/main/scala/akka/persistence/typed/scaladsl/Effect.scala

@@ -4,7 +4,6 @@
 
 package akka.persistence.typed.scaladsl
 
-import akka.actor.typed.scaladsl.Behaviors
 import akka.annotation.DoNotInherit
 import akka.persistence.typed.internal._
 

akka-persistence-typed/src/test/scala/akka/persistence/typed/scaladsl/PersistentActorCompileOnlyTest.scala

@@ -6,7 +6,7 @@ package akka.persistence.typed.scaladsl
 
 import scala.concurrent.ExecutionContext
 import scala.concurrent.duration._
-import akka.actor.typed.{ ActorRef, ActorSystem, Behavior, Terminated }
+import akka.actor.typed.{ ActorRef, Behavior }
 import akka.actor.typed.scaladsl.Behaviors
 import akka.actor.typed.scaladsl.ActorContext
 import akka.actor.typed.scaladsl.TimerScheduler

akka-persistence/src/main/scala/akka/persistence/PersistentActor.scala

@@ -9,7 +9,6 @@ import java.lang.{ Iterable ⇒ JIterable }
 import akka.actor._
 import akka.japi.Procedure
 import akka.japi.Util
-import akka.persistence.Eventsourced.{ AsyncHandlerInvocation, StashingHandlerInvocation }
 import com.typesafe.config.Config
 import scala.collection.immutable
 import scala.util.control.NoStackTrace

akka-persistence/src/main/scala/akka/persistence/journal/AsyncWriteJournal.scala

@@ -15,7 +15,6 @@ import scala.concurrent.Future
 import scala.util.{ Failure, Success, Try }
 import scala.util.control.NonFatal
 import akka.pattern.CircuitBreaker
-import java.util.Locale
 
 /**
  * Abstract journal, optimized for asynchronous, non-blocking writes.

akka-persistence/src/main/scala/akka/persistence/serialization/MessageSerializer.scala

@@ -15,7 +15,6 @@ import scala.collection.immutable.VectorBuilder
 import scala.concurrent.duration
 import akka.actor.Actor
 import scala.concurrent.duration.Duration
-import scala.language.existentials
 import java.io.NotSerializableException
 
 /**

akka-persistence/src/test/scala/akka/persistence/RecoveryPermitterSpec.scala

@@ -8,8 +8,6 @@ import scala.concurrent.duration._
 import scala.util.control.NoStackTrace
 
 import akka.actor._
-import akka.event.Logging
-import akka.event.Logging.Warning
 import akka.testkit.{ EventFilter, ImplicitSender, TestEvent }
 import com.typesafe.config.ConfigFactory
 import akka.testkit.TestProbe

akka-persistence/src/test/scala/akka/persistence/TimerPersistentActorSpec.scala

@@ -7,17 +7,11 @@ package akka.persistence
 import scala.concurrent.duration._
 import scala.runtime.BoxedUnit
 import scala.runtime.BoxedUnit
-import scala.util.control.NoStackTrace
 
-import akka.actor
 import akka.actor._
-import akka.event.Logging
-import akka.event.Logging.Warning
 import akka.japi.Procedure
-import akka.testkit.{ EventFilter, ImplicitSender, TestEvent }
+import akka.testkit.{ EventFilter, ImplicitSender }
 import com.typesafe.config.ConfigFactory
-import akka.testkit.TestProbe
-import akka.testkit.TestActors
 import akka.testkit.TestEvent.Mute
 
 object TimerPersistentActorSpec {

akka-persistence/src/test/scala/akka/persistence/fsm/PersistentFSMSpec.scala

@@ -9,7 +9,6 @@ import java.io.File
 import akka.actor.{ ActorSystem, _ }
 import akka.persistence._
 import akka.persistence.fsm.PersistentFSM._
-import akka.persistence.fsm.PersistentFSMSpec.IntAdded
 import akka.testkit._
 import com.typesafe.config.{ Config, ConfigFactory }
 import org.apache.commons.io.FileUtils

akka-stream-tests/src/test/scala/akka/stream/ActorMaterializerSpec.scala

@@ -8,11 +8,11 @@ import akka.Done
 import akka.actor.{ Actor, ActorSystem, PoisonPill, Props }
 import akka.stream.ActorMaterializerSpec.ActorWithMaterializer
 import akka.stream.impl.{ PhasedFusingActorMaterializer, StreamSupervisor }
-import akka.stream.scaladsl.{ Flow, Sink, Source }
+import akka.stream.scaladsl.{ Sink, Source }
 import akka.stream.testkit.{ StreamSpec, TestPublisher }
-import akka.testkit.{ ImplicitSender, TestActor, TestLatch, TestProbe }
+import akka.testkit.{ ImplicitSender, TestActor, TestProbe }
 
-import scala.concurrent.{ Await, Future }
+import scala.concurrent.Await
 import scala.concurrent.duration._
 import scala.util.{ Failure, Try }
 

akka-stream-tests/src/test/scala/akka/stream/DslFactoriesConsistencySpec.scala

@@ -189,7 +189,6 @@ class DslFactoriesConsistencySpec extends WordSpec with Matchers {
   def returnTypeString(m: Method): String =
     m.returnType.getName.drop("akka.stream.".length)
 
-  import language.existentials
   case class Method(name: String, parameterTypes: List[Class[_]], returnType: Class[_], declaringClass: Class[_])
 
   sealed trait MatchResult {

akka-stream-tests/src/test/scala/akka/stream/impl/LinearTraversalBuilderSpec.scala

@@ -6,7 +6,6 @@ package akka.stream.impl
 
 import akka.NotUsed
 import akka.stream._
-import akka.stream.impl.StreamLayout.AtomicModule
 import akka.stream.impl.TraversalTestUtils._
 import akka.stream.scaladsl.Keep
 import akka.testkit.AkkaSpec

akka-stream-tests/src/test/scala/akka/stream/impl/TimeoutsSpec.scala

@@ -4,7 +4,7 @@
 
 package akka.stream.impl
 
-import java.util.concurrent.{ TimeUnit, TimeoutException }
+import java.util.concurrent.TimeoutException
 
 import akka.Done
 import akka.stream.scaladsl._
@@ -361,7 +361,6 @@ class TimeoutsSpec extends StreamSpec {
 class TimeoutChecksSpec extends WordSpecLike with Matchers {
 
   "Timeout check interval" must {
-    import scala.concurrent.duration.{ Duration, FiniteDuration }
 
     "run twice for timeouts under 800ms" in {
       Timers.timeoutCheckInterval(800.millis) should ===(100.millis)

akka-stream-tests/src/test/scala/akka/stream/impl/TraversalBuilderSpec.scala

@@ -6,7 +6,6 @@ package akka.stream.impl
 
 import akka.NotUsed
 import akka.stream._
-import akka.stream.impl.TraversalBuilder.printTraversal
 import akka.stream.impl.TraversalTestUtils._
 import akka.stream.scaladsl.{ BidiFlow, Flow, Keep, Sink, Source }
 import akka.stream.testkit.{ TestPublisher, TestSubscriber }

akka-stream-tests/src/test/scala/akka/stream/impl/fusing/ActorGraphInterpreterSpec.scala

@@ -5,7 +5,6 @@
 package akka.stream.impl.fusing
 
 import java.util.concurrent.CountDownLatch
-import java.util.concurrent.atomic.AtomicInteger
 
 import akka.Done
 import akka.stream._

akka-stream-tests/src/test/scala/akka/stream/impl/fusing/GraphInterpreterSpecKit.scala

@@ -11,10 +11,8 @@ import akka.stream.impl.fusing.GraphInterpreter.{ Connection, DownstreamBoundary
 import akka.stream.stage.{ GraphStage, GraphStageLogic, InHandler, OutHandler, _ }
 import akka.stream.testkit.StreamSpec
 import akka.stream.testkit.Utils.TE
-import akka.util.OptionVal
 
 import scala.collection.{ Map ⇒ SMap }
-import scala.language.existentials
 
 object GraphInterpreterSpecKit {
 

akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterSpec.scala

@@ -12,7 +12,6 @@ import akka.stream.impl.fusing.GraphStages.SimpleLinearGraphStage
 import akka.util.ConstantFun
 
 class InterpreterSpec extends StreamSpec with GraphInterpreterSpecKit {
-  import Supervision.stoppingDecider
 
   /*
    * These tests were written for the previous version of the interpreter, the so called OneBoundedInterpreter.

akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterStressSpec.scala

@@ -10,7 +10,6 @@ import akka.testkit.LongRunningTest
 import akka.util.ConstantFun
 
 class InterpreterStressSpec extends StreamSpec with GraphInterpreterSpecKit {
-  import Supervision.stoppingDecider
 
   val chainLength = 1000 * 1000
   val halfLength = chainLength / 2

akka-stream-tests/src/test/scala/akka/stream/impl/fusing/InterpreterSupervisionSpec.scala

@@ -7,14 +7,9 @@ package akka.stream.impl.fusing
 import akka.stream.testkit.StreamSpec
 
 import scala.util.control.NoStackTrace
-import akka.stream.{ ActorAttributes, Attributes, Supervision }
+import akka.stream.Supervision
-import akka.stream.stage._
-import akka.testkit.AkkaSpec
 
 class InterpreterSupervisionSpec extends StreamSpec with GraphInterpreterSpecKit {
-  import Supervision.stoppingDecider
-  import Supervision.resumingDecider
-  import Supervision.restartingDecider
 
   val TE = new Exception("TEST") with NoStackTrace {
     override def toString = "TE"

akka-stream-tests/src/test/scala/akka/stream/impl/fusing/LifecycleInterpreterSpec.scala

@@ -13,7 +13,6 @@ import akka.stream.testkit.Utils.TE
 import scala.concurrent.duration._
 
 class LifecycleInterpreterSpec extends StreamSpec with GraphInterpreterSpecKit {
-  import akka.stream.Supervision._
 
   "Interpreter" must {
 

akka-stream-tests/src/test/scala/akka/stream/io/FileSinkSpec.scala

@@ -16,9 +16,8 @@ import akka.stream.scaladsl.{ FileIO, Sink, Source }
 import akka.stream.testkit._
 import akka.stream.testkit.Utils._
 import akka.stream._
-import akka.util.{ ByteString, Timeout }
+import akka.util.ByteString
 import com.google.common.jimfs.{ Configuration, Jimfs }
-import org.scalatest.BeforeAndAfterAll
 
 import scala.collection.mutable.ListBuffer
 import scala.concurrent.{ Await, Future }

akka-stream-tests/src/test/scala/akka/stream/io/OutputStreamSourceSpec.scala

@@ -14,7 +14,7 @@ import akka.stream._
 import akka.stream.impl.{ PhasedFusingActorMaterializer, StreamSupervisor }
 import akka.stream.impl.StreamSupervisor.Children
 import akka.stream.impl.io.OutputStreamSourceStage
-import akka.stream.scaladsl.{ Keep, Sink, Source, StreamConverters }
+import akka.stream.scaladsl.{ Keep, Sink, StreamConverters }
 import akka.stream.testkit.Utils._
 import akka.stream.testkit._
 import akka.stream.testkit.scaladsl.TestSink

akka-stream-tests/src/test/scala/akka/stream/io/compression/CoderSpec.scala

@@ -5,7 +5,6 @@
 package akka.stream.io.compression
 
 import java.io.{ ByteArrayInputStream, ByteArrayOutputStream, InputStream, OutputStream }
-import java.util
 import java.util.concurrent.ThreadLocalRandom
 import java.util.zip.DataFormatException
 

akka-stream-tests/src/test/scala/akka/stream/scaladsl/CompressionSpec.scala

@@ -8,7 +8,6 @@ import java.nio.charset.StandardCharsets
 
 import akka.stream.impl.io.compression.{ DeflateCompressor, GzipCompressor }
 import akka.stream.testkit.StreamSpec
-import akka.stream.testkit.scaladsl.TestSink
 import akka.stream.{ ActorMaterializer, ActorMaterializerSettings }
 import akka.util.ByteString
 

akka-stream-tests/src/test/scala/akka/stream/scaladsl/CoupledTerminationFlowSpec.scala

@@ -7,7 +7,7 @@ package akka.stream.scaladsl
 import akka.{ Done, NotUsed }
 import akka.stream._
 import akka.stream.testkit._
-import akka.stream.testkit.scaladsl.{ TestSink, TestSource }
+import akka.stream.testkit.scaladsl.TestSource
 import akka.testkit.TestProbe
 import org.reactivestreams.{ Publisher, Subscriber, Subscription }
 import org.scalatest.Assertion

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FailedSourceSpec.scala

@@ -5,13 +5,9 @@
 package akka.stream.scaladsl
 
 import akka.stream.ActorMaterializer
-import akka.stream.testkit.{ StreamSpec, TestSubscriber, Utils }
+import akka.stream.testkit.{ StreamSpec, TestSubscriber }
 import akka.testkit.DefaultTimeout
-import org.scalatest.time.{ Millis, Span }
 
-import scala.concurrent.Await
-import scala.concurrent.duration._
-import scala.util.Failure
 import scala.util.control.NoStackTrace
 
 class FailedSourceSpec extends StreamSpec with DefaultTimeout {

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowAskSpec.scala

@@ -4,25 +4,19 @@
 
 package akka.stream.scaladsl
 
-import java.util.concurrent.{ CountDownLatch, LinkedBlockingQueue, ThreadLocalRandom }
+import java.util.concurrent.ThreadLocalRandom
-import java.util.concurrent.atomic.AtomicInteger
 
 import akka.actor.{ Actor, ActorRef, PoisonPill, Props }
-import akka.stream.ActorAttributes.{ SupervisionStrategy, supervisionStrategy }
+import akka.stream.ActorAttributes.supervisionStrategy
 import akka.stream.{ ActorAttributes, ActorMaterializer, Supervision }
 import akka.stream.Supervision.resumingDecider
-import akka.stream.impl.ReactiveStreamsCompliance
 import akka.stream.testkit.Utils._
 import akka.stream.testkit._
-import akka.stream.testkit.scaladsl.TestSink
+import akka.testkit.{ TestActors, TestProbe }
-import akka.testkit.{ TestActors, TestLatch, TestProbe }
-import org.scalatest.concurrent.PatienceConfiguration.Timeout
 
-import scala.annotation.tailrec
+import scala.concurrent.{ Await, Future }
-import scala.concurrent.{ Await, Future, Promise }
 import scala.concurrent.duration._
 import scala.reflect.ClassTag
-import scala.util.control.NoStackTrace
 
 object FlowAskSpec {
   case class Reply(payload: Int)

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowCollectTypeSpec.scala

@@ -4,9 +4,7 @@
 
 package akka.stream.scaladsl
 
-import java.util.concurrent.ThreadLocalRandom.{ current ⇒ random }
+import akka.stream.testkit.StreamSpec
-
-import akka.stream.testkit.{ ScriptedTest, StreamSpec }
 import akka.stream.{ ActorMaterializer, ActorMaterializerSettings }
 
 class FlowCollectTypeSpec extends StreamSpec {

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowFoldAsyncSpec.scala

@@ -11,7 +11,6 @@ import akka.stream.Supervision.{ restartingDecider, resumingDecider }
 import akka.stream.impl.ReactiveStreamsCompliance
 import akka.stream.testkit.Utils._
 import akka.stream.testkit._
-import akka.testkit.TestLatch
 import org.scalatest.concurrent.PatienceConfiguration.Timeout
 
 import scala.concurrent.duration._

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowGroupBySpec.scala

@@ -21,8 +21,6 @@ import akka.stream.impl.fusing.GroupBy
 import akka.stream.testkit._
 import akka.stream.testkit.Utils._
 import org.reactivestreams.Publisher
-import org.scalatest.concurrent.ScalaFutures
-import org.scalactic.ConversionCheckedTripleEquals
 import org.scalatest.concurrent.PatienceConfiguration.Timeout
 import akka.stream.testkit.scaladsl.TestSource
 import akka.stream.testkit.scaladsl.TestSink

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowGroupedWithinSpec.scala

@@ -12,7 +12,6 @@ import akka.stream.{ ActorMaterializer, ActorMaterializerSettings, ThrottleMode
 import akka.stream.testkit._
 import akka.stream.testkit.Utils._
 
-import scala.concurrent.Await
 import akka.testkit.TimingTest
 import akka.util.ConstantFun
 

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowLogSpec.scala

@@ -11,7 +11,7 @@ import akka.stream.Attributes.LogLevels
 import akka.stream.Supervision._
 import akka.stream.testkit.{ StreamSpec, ScriptedTest }
 import akka.stream._
-import akka.testkit.{ AkkaSpec, TestProbe }
+import akka.testkit.TestProbe
 
 import scala.concurrent.duration._
 import scala.concurrent.Await

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowMapAsyncSpec.scala

@@ -7,7 +7,7 @@ package akka.stream.scaladsl
 import java.util.concurrent.{ LinkedBlockingQueue, ThreadLocalRandom }
 import java.util.concurrent.atomic.AtomicInteger
 
-import akka.stream.ActorAttributes.{ SupervisionStrategy, supervisionStrategy }
+import akka.stream.ActorAttributes.supervisionStrategy
 import akka.stream.{ ActorAttributes, ActorMaterializer, Supervision }
 import akka.stream.Supervision.resumingDecider
 import akka.stream.impl.ReactiveStreamsCompliance
@@ -406,7 +406,6 @@ class FlowMapAsyncSpec extends StreamSpec {
     }
 
     "not invoke the decider twice for the same already failed future" in {
-      import system.dispatcher
       val failCount = new AtomicInteger(0)
       val result = Source(List(true, false))
         .mapAsync(1)(elem ⇒

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowScanAsyncSpec.scala

@@ -4,7 +4,7 @@
 
 package akka.stream.scaladsl
 
-import akka.{ NotUsed, pattern }
+import akka.pattern
 import akka.stream.{ ActorAttributes, ActorMaterializer, Supervision }
 import akka.stream.impl.ReactiveStreamsCompliance
 import akka.stream.testkit.TestSubscriber.Probe

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowSpec.scala

@@ -8,23 +8,18 @@ import java.util.concurrent.ThreadLocalRandom
 
 import akka.NotUsed
 import akka.actor._
-import akka.stream.Supervision._
 import akka.stream.impl._
-import akka.stream.impl.fusing.ActorGraphInterpreter
 import akka.stream.testkit.Utils._
 import akka.stream.testkit._
 import akka.stream._
-import akka.testkit.TestEvent.{ Mute, UnMute }
+import akka.testkit.TestDuration
-import akka.testkit.{ EventFilter, TestDuration }
 import com.typesafe.config.ConfigFactory
 import org.reactivestreams.{ Publisher, Subscriber }
-import org.scalatest.concurrent.ScalaFutures
 
 import scala.collection.immutable
 import scala.concurrent.Await
 import scala.concurrent.duration._
 import scala.util.control.NoStackTrace
-import akka.stream.impl.fusing.GraphInterpreterShell
 
 object FlowSpec {
   class Fruit

akka-stream-tests/src/test/scala/akka/stream/scaladsl/FutureFlattenSourceSpec.scala

@@ -6,7 +6,6 @@ package akka.stream.scaladsl
 
 import java.util.concurrent.{ CompletableFuture, TimeUnit }
 
-import akka.Done
 import akka.stream._
 import akka.stream.stage.{ GraphStageLogic, GraphStageWithMaterializedValue }
 import akka.stream.testkit.Utils.{ TE, assertAllStagesStopped }

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphBalanceSpec.scala

@@ -11,7 +11,6 @@ import akka.stream._
 import akka.stream.testkit._
 import akka.stream.testkit.scaladsl._
 import akka.stream.testkit.Utils._
-import akka.util.ByteString
 
 class GraphBalanceSpec extends StreamSpec {
 

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphDSLCompileSpec.scala

@@ -4,7 +4,6 @@
 
 package akka.stream.scaladsl
 
-import akka.NotUsed
 import akka.stream.impl.fusing.GraphStages
 import akka.stream._
 import akka.stream.testkit._
@@ -365,7 +364,6 @@ class GraphDSLCompileSpec extends StreamSpec {
     "suitably override attribute handling methods" in {
       import akka.stream.Attributes._
       val ga = GraphDSL.create() { implicit b ⇒
-        import GraphDSL.Implicits._
         val id = b.add(GraphStages.identity[Any])
 
         FlowShape(id.in, id.out)

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMergePrioritizedSpec.scala

@@ -5,7 +5,6 @@
 package akka.stream.scaladsl
 
 import akka.NotUsed
-import akka.stream.impl.Throttle
 import akka.stream.testkit.TestSubscriber.ManualProbe
 import akka.stream.{ ClosedShape, Inlet, Outlet }
 import akka.stream.testkit.{ TestSubscriber, TwoStreamsSetup }

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphMergeSortedSpec.scala

@@ -8,9 +8,6 @@ import akka.stream._
 import akka.stream.testkit.TwoStreamsSetup
 import org.scalacheck.Gen
 import org.scalatest.prop.GeneratorDrivenPropertyChecks
-import org.scalatest.concurrent.ScalaFutures
-import scala.concurrent.duration._
-import org.scalactic.ConversionCheckedTripleEquals
 import org.scalacheck.Shrink
 
 class GraphMergeSortedSpec extends TwoStreamsSetup with GeneratorDrivenPropertyChecks {

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphPartitionSpec.scala

@@ -7,7 +7,6 @@ package akka.stream.scaladsl
 import akka.stream.testkit._
 import akka.stream.{ OverflowStrategy, ActorMaterializer, ActorMaterializerSettings, ClosedShape }
 import akka.stream.testkit.Utils._
-import org.scalatest.concurrent.ScalaFutures
 import scala.concurrent.Await
 import scala.concurrent.duration._
 

akka-stream-tests/src/test/scala/akka/stream/scaladsl/GraphZipNSpec.scala

@@ -8,7 +8,6 @@ import akka.stream.testkit._
 import akka.stream.testkit.Utils._
 import akka.stream._
 
-import scala.concurrent.Await
 import scala.concurrent.duration._
 import scala.collection.immutable
 

akka-stream-tests/src/test/scala/akka/stream/scaladsl/HeadSinkSpec.scala

@@ -7,7 +7,7 @@ package akka.stream.scaladsl
 import scala.concurrent.Await
 import scala.concurrent.Future
 import scala.concurrent.duration._
-import akka.stream.{ AbruptStageTerminationException, AbruptTerminationException, ActorMaterializer, ActorMaterializerSettings }
+import akka.stream.{ AbruptTerminationException, ActorMaterializer, ActorMaterializerSettings }
 import akka.stream.testkit._
 import akka.stream.testkit.Utils._
 

akka-stream-tests/src/test/scala/akka/stream/scaladsl/LazyFlowSpec.scala

@@ -6,6 +6,8 @@ package akka.stream.scaladsl
 
 import akka.NotUsed
 import akka.stream._
+import akka.stream.stage.{ GraphStageLogic, GraphStageWithMaterializedValue }
+import akka.stream.testkit.{ StreamSpec, TestPublisher }
 import akka.stream.testkit.Utils._
 import akka.stream.testkit.scaladsl.{ TestSink, TestSource }
 import akka.stream.testkit.{ StreamSpec, TestPublisher }

akka-stream-tests/src/test/scala/akka/stream/scaladsl/LazySourceSpec.scala

@@ -8,7 +8,7 @@ import java.util.concurrent.atomic.AtomicBoolean
 
 import akka.Done
 import akka.stream.impl.LazySource
-import akka.stream.stage.{ GraphStage, GraphStageLogic, OutHandler }
+import akka.stream.stage.{ GraphStage, GraphStageLogic }
 import akka.stream.testkit.Utils.{ TE, assertAllStagesStopped }
 import akka.stream.testkit.{ StreamSpec, TestPublisher, TestSubscriber }
 import akka.stream.{ ActorMaterializer, Attributes, Outlet, SourceShape }

akka-stream-tests/src/test/scala/akka/stream/scaladsl/MaybeSourceSpec.scala

@@ -7,11 +7,8 @@ package akka.stream.scaladsl
 import akka.stream.{ AbruptStageTerminationException, ActorMaterializer }
 import akka.stream.testkit.{ StreamSpec, TestSubscriber, Utils }
 import akka.testkit.DefaultTimeout
-import org.scalatest.time.{ Millis, Span }
 
 import scala.concurrent.duration._
-import scala.concurrent.Await
-import scala.util.Failure
 import scala.util.control.NoStackTrace
 
 class MaybeSourceSpec extends StreamSpec with DefaultTimeout {

akka-stream-tests/src/test/scala/akka/stream/scaladsl/ReverseArrowSpec.scala

@@ -8,7 +8,6 @@ import akka.stream.testkit._
 import akka.stream._
 import scala.concurrent.Await
 import scala.concurrent.duration._
-import org.scalactic.ConversionCheckedTripleEquals
 
 class ReverseArrowSpec extends StreamSpec {
   import GraphDSL.Implicits._

akka-stream-tests/src/test/scala/akka/stream/scaladsl/SourceSpec.scala

@@ -5,12 +5,9 @@
 package akka.stream.scaladsl
 
 import akka.testkit.DefaultTimeout
-import org.scalatest.concurrent.ScalaFutures
 import org.scalatest.time.{ Span, Millis }
-import scala.concurrent.{ Await, Future, Promise }
+import scala.concurrent.{ Await, Future }
 import scala.concurrent.duration._
-import scala.util.Failure
-import scala.util.control.NoStackTrace
 import akka.stream._
 import akka.stream.testkit._
 import akka.NotUsed

akka-stream-tests/src/test/scala/akka/stream/scaladsl/StreamRefsSpec.scala

@@ -4,7 +4,7 @@
 
 package akka.stream.scaladsl
 
-import akka.{ Done, NotUsed }
+import akka.NotUsed
 import akka.actor.Status.Failure
 import akka.actor.{ Actor, ActorIdentity, ActorLogging, ActorRef, ActorSystem, ActorSystemImpl, Identify, Props }
 import akka.pattern._
@@ -12,13 +12,11 @@ import akka.stream.testkit.TestPublisher
 import akka.stream.testkit.scaladsl._
 import akka.stream._
 import akka.testkit.{ AkkaSpec, ImplicitSender, SocketUtil, TestKit, TestProbe }
-import akka.util.{ ByteString, PrettyDuration }
+import akka.util.ByteString
 import com.typesafe.config._
 
-import scala.collection.immutable
 import scala.concurrent.duration._
 import scala.concurrent.Future
-import scala.util.Success
 import scala.util.control.NoStackTrace
 
 object StreamRefsSpec {

akka-stream-tests/src/test/scala/akka/stream/scaladsl/UnfoldResourceAsyncSourceSpec.scala

@@ -4,7 +4,7 @@
 
 package akka.stream.scaladsl
 
-import java.util.concurrent.atomic.{ AtomicBoolean, AtomicInteger }
+import java.util.concurrent.atomic.AtomicInteger
 
 import akka.Done
 import akka.actor.ActorSystem