diff --git a/.travis.yml b/.travis.yml
index 15a17c13ed..4edcc179cb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -38,7 +38,7 @@ jobs:
     - stage: scala3
       name: scala3
       # separate job since only a few modules compile with Scala 3 yet
-      script: jabba install adopt@1.11-0 && jabba use adopt@1.11-0 && sbt -Dakka.build.scalaVersion=3.0 "akka-actor-tests/test:compile" akka-actor-testkit-typed/compile akka-actor-typed/compile akka-discovery/test akka-pki/test:compile akka-protobuf/test:compile akka-protobuf-v3/test:compile akka-slf4j/test:compile akka-stream/compile akka-stream-tests-tck/test akka-coordination/test akka-serialization-jackson/test:compile akka-testkit/test akka-stream-testkit/test akka-remote/compile
+      script: jabba install adopt@1.11-0 && jabba use adopt@1.11-0 && sbt -jvm-opts .jvmopts-travis -Dakka.build.scalaVersion=3.0 "akka-actor-tests/test:compile" akka-actor-testkit-typed/compile akka-actor-typed/compile akka-actor-typed-tests/test akka-discovery/test akka-pki/test:compile akka-protobuf/test:compile akka-protobuf-v3/test:compile akka-slf4j/test:compile akka-stream/compile akka-stream-tests-tck/test akka-coordination/test akka-serialization-jackson/test:compile akka-testkit/test akka-stream-testkit/test akka-remote/compile
 
 stages:
   - name: whitesource
diff --git a/akka-actor-tests/src/test/java/akka/actor/AbstractFSMActorTest.java b/akka-actor-tests/src/test/java/akka/actor/AbstractFSMActorTest.java
index d30f53fb8d..2f12d9414d 100644
--- a/akka-actor-tests/src/test/java/akka/actor/AbstractFSMActorTest.java
+++ b/akka-actor-tests/src/test/java/akka/actor/AbstractFSMActorTest.java
@@ -13,6 +13,8 @@ import org.scalatestplus.junit.JUnitSuite;
 
 public class AbstractFSMActorTest extends JUnitSuite {
 
+  // javac produces an `unchecked` warning about `akka$actor$FSM$$transitionEvent`
+  // https://github.com/lampepfl/dotty/issues/6350
   public static class MyFSM extends AbstractFSM<String, String> {
 
     private final ActorRef probe;
diff --git a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java
index dd28926550..8443c1da0e 100644
--- a/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java
+++ b/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/IntroTest.java
@@ -147,15 +147,6 @@ public interface IntroTest {
   // #hello-world-main
 
   interface CustomDispatchersExample {
-
-    public static class SayHello {
-      public final String name;
-
-      public SayHello(String name) {
-        this.name = name;
-      }
-    }
-
     // #hello-world-main-with-dispatchers
     public class HelloWorldMain extends AbstractBehavior<HelloWorldMain.SayHello> {
 
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala
index 258a715221..d504ca2503 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorContextSpec.scala
@@ -647,7 +647,8 @@ abstract class ActorContextSpec extends ScalaTestWithActorTestKit with AnyWordSp
     }
 
     "not allow null messages" in {
-      val actor = spawn(Behaviors.empty[Null].decorate)
+      // Scala 3 doesn't generate an implicit `ClassTag[Null]` (https://github.com/lampepfl/dotty/issues/9586)
+      val actor = spawn(decoration(ClassTag.Null)(Behaviors.empty[Null]))
       intercept[InvalidMessageException] {
         actor ! null
       }
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorRefIgnoreSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorRefIgnoreSpec.scala
index f989dbabca..92901208ca 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorRefIgnoreSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ActorRefIgnoreSpec.scala
@@ -44,7 +44,7 @@ class ActorRefIgnoreSpec extends ScalaTestWithActorTestKit() with AnyWordSpecLik
     implicit val timeout: Timeout = 1.second
 
     // send a message to interactWithRef
-    context.ask(askMeRef, Request) {
+    context.ask(askMeRef, Request.apply) {
       case Success(res) => res
       case Failure(ex)  => throw ex
     }
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala
index a9aad8f79b..58dfae00ac 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/AskSpec.scala
@@ -50,7 +50,7 @@ class AskSpec extends ScalaTestWithActorTestKit("""
   "Ask pattern" must {
     "fail the future if the actor is already terminated" in {
       val ref = spawn(behavior)
-      val stopResult: Future[Unit] = ref.ask(Stop)
+      val stopResult: Future[Unit] = ref.ask(Stop.apply)
       stopResult.futureValue
 
       val probe = createTestProbe()
@@ -131,7 +131,7 @@ class AskSpec extends ScalaTestWithActorTestKit("""
         import akka.actor.typed.scaladsl.adapter._
         implicit val timeout: Timeout = 3.seconds
         val typedLegacy: ActorRef[AnyRef] = legacyActor
-        (typedLegacy.ask(Ping)).failed.futureValue should ===(ex)
+        typedLegacy.ask(Ping.apply).failed.futureValue should ===(ex)
       } finally {
         akka.testkit.TestKit.shutdownActorSystem(classicSystem)
       }
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala
index 74a0e7d312..7914c5ca2b 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/BehaviorSpec.scala
@@ -448,7 +448,7 @@ class MutableScalaBehaviorSpec extends Messages with Become with Stoppable {
         override def onMessage(message: Command): Behavior[Command] = {
           message match {
             case GetSelf =>
-              monitor ! Self(context.self)
+              monitor ! Self(this.context.self)
               this
             case Miss =>
               monitor ! Missed
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ExtensionsSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ExtensionsSpec.scala
index 9dee4cba6a..af9db0ab67 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ExtensionsSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/ExtensionsSpec.scala
@@ -263,7 +263,9 @@ class ExtensionsSpec extends ScalaTestWithActorTestKit with AnyWordSpecLike with
     }
     val sys = setup match {
       case None    => ActorSystem[Any](Behaviors.empty[Any], name, bootstrap)
-      case Some(s) => ActorSystem[Any](Behaviors.empty[Any], name, s.and(bootstrap))
+      case Some(s) =>
+        // explicit Props.empty: https://github.com/lampepfl/dotty/issues/12679
+        ActorSystem[Any](Behaviors.empty[Any], name, s.and(bootstrap), Props.empty)
     }
 
     try f(sys)
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/MailboxSelectorSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/MailboxSelectorSpec.scala
index 655836fad2..a4a1ef68a7 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/MailboxSelectorSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/MailboxSelectorSpec.scala
@@ -51,13 +51,13 @@ class MailboxSelectorSpec extends ScalaTestWithActorTestKit("""
   "The Mailbox selectors" must {
     "default to unbounded" in {
       val actor = spawn(behavior)
-      val mailbox = actor.ask(WhatsYourMailbox).futureValue
+      val mailbox = actor.ask(WhatsYourMailbox.apply).futureValue
       mailbox shouldBe a[UnboundedMessageQueueSemantics]
     }
 
     "select a bounded mailbox" in {
       val actor = spawn(behavior, MailboxSelector.bounded(3))
-      val mailbox = actor.ask(WhatsYourMailbox).futureValue
+      val mailbox = actor.ask(WhatsYourMailbox.apply).futureValue
       mailbox shouldBe a[BoundedMessageQueueSemantics]
       // capacity is private so only way to test is to fill mailbox
     }
@@ -85,7 +85,7 @@ class MailboxSelectorSpec extends ScalaTestWithActorTestKit("""
 
     "select an arbitrary mailbox from config" in {
       val actor = spawn(behavior, MailboxSelector.fromConfig("specific-mailbox"))
-      val mailbox = actor.ask(WhatsYourMailbox).futureValue
+      val mailbox = actor.ask(WhatsYourMailbox.apply).futureValue
       mailbox shouldBe a[BoundedMessageQueueSemantics]
       mailbox.asInstanceOf[BoundedNodeMessageQueue].capacity should ===(4)
 
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala
index 1141f87872..8fd28930b0 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/ActorContextAskSpec.scala
@@ -53,7 +53,7 @@ class ActorContextAskSpec
       val snitch = Behaviors.setup[Pong] { context =>
         // Timeout comes from TypedAkkaSpec
 
-        context.ask(pingPong, Ping) {
+        context.ask(pingPong, Ping.apply) {
           case Success(_)  => Pong(context.self.path.name + "1", Thread.currentThread().getName)
           case Failure(ex) => throw ex
         }
@@ -86,7 +86,7 @@ class ActorContextAskSpec
       })
 
       val snitch = Behaviors.setup[AnyRef] { context =>
-        context.ask(pingPong, Ping) {
+        context.ask(pingPong, Ping.apply) {
           case Success(message) => throw new NotImplementedError(message.toString)
           case Failure(x)       => x
         }
@@ -194,7 +194,7 @@ class ActorContextAskSpec
 
       val probe = createTestProbe[Any]()
       spawn(Behaviors.setup[Pong.type] { ctx =>
-        ctx.askWithStatus(probe.ref, Ping) {
+        ctx.askWithStatus(probe.ref, Ping.apply) {
           case Success(Pong) => Pong
           case Failure(ex)   => throw ex
         }
@@ -217,7 +217,7 @@ class ActorContextAskSpec
 
       val probe = createTestProbe[Any]()
       spawn(Behaviors.setup[Throwable] { ctx =>
-        ctx.askWithStatus(probe.ref, Ping) {
+        ctx.askWithStatus(probe.ref, Ping.apply) {
           case Failure(ex) => ex
           case wat         => throw new IllegalArgumentException(s"Unexpected response $wat")
         }
@@ -241,7 +241,7 @@ class ActorContextAskSpec
       val probe = createTestProbe[Any]()
       case class Message(any: Any)
       spawn(Behaviors.setup[Throwable] { ctx =>
-        ctx.askWithStatus(probe.ref, Ping) {
+        ctx.askWithStatus(probe.ref, Ping.apply) {
           case Failure(ex) => ex
           case wat         => throw new IllegalArgumentException(s"Unexpected response $wat")
         }
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala
index d27d66bc21..ae37f7f8dd 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/MessageAdapterSpec.scala
@@ -281,7 +281,7 @@ class MessageAdapterSpec
     val deadLetterProbe = testKit.createDeadLetterProbe()
 
     val snitch = Behaviors.setup[PingReply] { context =>
-      val replyTo = context.messageAdapter[Pong](PingReply)
+      val replyTo = context.messageAdapter[Pong](PingReply.apply)
       pingProbe.ref ! Ping(replyTo)
       Behaviors.stopped
     }
diff --git a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala
index 49f71abf36..a50bec47dd 100644
--- a/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/akka/actor/typed/scaladsl/StashSpec.scala
@@ -76,7 +76,7 @@ object AbstractStashSpec {
                   context.self ! Unstash // continue unstashing until buffer is empty
                   val numberOfMessages = 2
                   context.log.debug(s"Unstash $numberOfMessages of ${buffer.size}, starting with ${buffer.head}")
-                  buffer.unstash(unstashing(processed), numberOfMessages, Unstashed)
+                  buffer.unstash(unstashing(processed), numberOfMessages, Unstashed.apply)
                 }
               case Stash =>
                 Behaviors.unhandled
@@ -113,7 +113,7 @@ object AbstractStashSpec {
                   context.self ! Unstash // continue unstashing until buffer is empty
                   val numberOfMessages = 2
                   context.log.debug(s"Unstash $numberOfMessages of ${buffer.size}, starting with ${buffer.head}")
-                  buffer.unstash(unstashing(processed), numberOfMessages, Unstashed)
+                  buffer.unstash(unstashing(processed), numberOfMessages, Unstashed.apply)
                 }
               case GetStashSize(replyTo) =>
                 replyTo ! buffer.size
@@ -166,7 +166,7 @@ object AbstractStashSpec {
             context.self ! Unstash // continue unstashing until buffer is empty
             val numberOfMessages = 2
             context.log.debug(s"Unstash $numberOfMessages of ${buffer.size}, starting with ${buffer.head}")
-            buffer.unstash(this, numberOfMessages, Unstashed)
+            buffer.unstash(this, numberOfMessages, Unstashed.apply)
           }
         case Unstashed(message: Msg) =>
           context.log.debug(s"unstashed $message")
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala
index 90fd016901..447e1338fc 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/InteractionPatternsSpec.scala
@@ -80,7 +80,7 @@ class InteractionPatternsSpec extends ScalaTestWithActorTestKit with AnyWordSpec
       val probe = createTestProbe[CookieFabric.Response]()
       // shhh, don't tell anyone
       import scala.language.reflectiveCalls
-      val context = new {
+      val context: { def self: ActorRef[CookieFabric.Response] } = new {
         def self = probe.ref
       }
 
@@ -259,7 +259,7 @@ class InteractionPatternsSpec extends ScalaTestWithActorTestKit with AnyWordSpec
           // as OpenThePodBayDoorsPlease is a case class it has a factory apply method
           // that is what we are passing as the second parameter here it could also be written
           // as `ref => OpenThePodBayDoorsPlease(ref)`
-          context.ask(hal, Hal.OpenThePodBayDoorsPlease) {
+          context.ask(hal, Hal.OpenThePodBayDoorsPlease.apply) {
             case Success(Hal.Response(message)) => AdaptedResponse(message)
             case Failure(_)                     => AdaptedResponse("Request failed")
           }
@@ -269,7 +269,7 @@ class InteractionPatternsSpec extends ScalaTestWithActorTestKit with AnyWordSpec
           // changed at the time the response arrives and the transformation is done, best is to
           // use immutable state we have closed over like here.
           val requestId = 1
-          context.ask(hal, Hal.OpenThePodBayDoorsPlease) {
+          context.ask(hal, Hal.OpenThePodBayDoorsPlease.apply) {
             case Success(Hal.Response(message)) => AdaptedResponse(s"$requestId: $message")
             case Failure(_)                     => AdaptedResponse(s"$requestId: Request failed")
           }
@@ -324,7 +324,7 @@ class InteractionPatternsSpec extends ScalaTestWithActorTestKit with AnyWordSpec
 
           // A StatusReply.Success(m) ends up as a Success(m) here, while a
           // StatusReply.Error(text) becomes a Failure(ErrorMessage(text))
-          context.askWithStatus(hal, Hal.OpenThePodBayDoorsPlease) {
+          context.askWithStatus(hal, Hal.OpenThePodBayDoorsPlease.apply) {
             case Success(message)                        => AdaptedResponse(message)
             case Failure(StatusReply.ErrorMessage(text)) => AdaptedResponse(s"Request denied: $text")
             case Failure(_)                              => AdaptedResponse("Request failed")
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/OOIntroSpec.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/OOIntroSpec.scala
index ca453cd78a..7f715f7af4 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/OOIntroSpec.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/OOIntroSpec.scala
@@ -69,7 +69,7 @@ object OOIntroSpec {
       }
     }
 
-    object SessionBehavior {
+    private object SessionBehavior {
       def apply(
           room: ActorRef[PublishSessionMessage],
           screenName: String,
diff --git a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StyleGuideDocExamples.scala b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StyleGuideDocExamples.scala
index 47b0941cc4..8135746549 100644
--- a/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StyleGuideDocExamples.scala
+++ b/akka-actor-typed-tests/src/test/scala/docs/akka/typed/StyleGuideDocExamples.scala
@@ -485,14 +485,16 @@ object StyleGuideDocExamples {
       @nowarn
       private def counter(remaining: Int): Behavior[Command] = {
         //#pattern-match-without-guard
-        Behaviors.receiveMessage {
-          case Down =>
-            if (remaining == 1) {
-              notifyWhenZero.tell(Done)
-              zero
-            } else
-              counter(remaining - 1)
-        }
+        // `@unchecked` for Scala 3, which doesn't support @nowarn
+        Behaviors.receiveMessage(x =>
+          (x: @unchecked) match {
+            case Down =>
+              if (remaining == 1) {
+                notifyWhenZero.tell(Done)
+                zero
+              } else
+                counter(remaining - 1)
+          })
         //#pattern-match-without-guard
       }
 
diff --git a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala
index 66c0e38edf..9a99601759 100644
--- a/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala
+++ b/akka-actor-typed/src/main/scala/akka/actor/typed/javadsl/BehaviorBuilder.scala
@@ -167,6 +167,7 @@ object BehaviorBuilder {
   /**
    * @return new empty immutable behavior builder.
    */
+  // Empty param list to work around https://github.com/lampepfl/dotty/issues/10347
   def create[T]: BehaviorBuilder[T] = _empty.asInstanceOf[BehaviorBuilder[T]]
 }