Fix compiler warnings (#3344)

akka-http-caching/src/main/scala/akka/http/caching/scaladsl/Cache.scala

@@ -99,7 +99,7 @@ abstract class Cache[K, V] extends akka.http.caching.javadsl.Cache[K, V] {
    * Returns either the cached CompletionStage for the given key or the given value as a CompletionStage
    */
   override def getOrCreateStrict(key: K, block: Creator[V]): CompletionStage[V] =
-    futureToJava(get(key, () => block.create))
+    futureToJava(get(key, () => block.create()))
 
   /**
    * Returns the upper bound for the number of currently cached entries.

akka-http-core/src/main/scala/akka/http/impl/engine/client/PoolMasterActor.scala

@@ -224,7 +224,7 @@ private[http] final class PoolMasterActor extends Actor with ActorLogging {
 
 private[http] object PoolMasterActor {
 
-  val props = Props[PoolMasterActor].withDeploy(Deploy.local)
+  val props = Props[PoolMasterActor]().withDeploy(Deploy.local)
 
   sealed trait PoolInterfaceStatus
   final case class PoolInterfaceRunning(interface: PoolInterface) extends PoolInterfaceStatus

akka-http-core/src/main/scala/akka/http/impl/engine/parsing/HttpMessageParser.scala

@@ -118,10 +118,10 @@ private[http] trait HttpMessageParser[Output >: MessageOutput <: ParserOutput] {
       protocol = c(7) match {
         case '0' => `HTTP/1.0`
         case '1' => `HTTP/1.1`
-        case _   => onBadProtocol
+        case _   => onBadProtocol()
       }
       cursor + 8
-    } else onBadProtocol
+    } else onBadProtocol()
   }
 
   /**

akka-http-core/src/main/scala/akka/http/impl/engine/parsing/HttpResponseParser.scala

@@ -114,7 +114,7 @@ private[http] class HttpResponseParser(protected val settings: ParserSettings, p
       // Status format with no reason phrase and no trailing space accepted, diverging from the spec
       // See https://github.com/akka/akka-http/pull/989
       skipNewLine(cursor + 3)
-    } else badStatusCode
+    } else badStatusCode()
   }
 
   def handleInformationalResponses: Boolean = true

akka-http-core/src/main/scala/akka/http/impl/util/Rendering.scala

@@ -307,7 +307,7 @@ private[http] class ByteStringRendering(sizeHint: Int) extends Rendering {
   private[this] val builder = new ByteStringBuilder
   builder.sizeHint(sizeHint)
 
-  def get: ByteString = builder.result
+  def get: ByteString = builder.result()
 
   def ~~(char: Char): this.type = {
     builder += char.toByte

akka-http-core/src/main/scala/akka/http/impl/util/package.scala

@@ -71,7 +71,7 @@ package object util {
     if (bytes >= unit) {
       val exp = (math.log(bytes.toDouble) / math.log(unit)).toInt
       val pre = if (si) "kMGTPE".charAt(exp - 1).toString else "KMGTPE".charAt(exp - 1).toString + 'i'
-      "%.1f %sB" format (bytes / math.pow(unit, exp), pre)
+      "%.1f %sB".format(bytes / math.pow(unit, exp), pre)
     } else bytes.toString + "  B"
   }
 

akka-http-core/src/main/scala/akka/http/scaladsl/Http.scala

@@ -481,7 +481,7 @@ class HttpExt private[http] (private val config: Config)(implicit val system: Ex
   private[akka] def newHostConnectionPool[T](setup: HostConnectionPoolSetup)(
     implicit
     fm: Materializer): Flow[(HttpRequest, T), (Try[HttpResponse], T), HostConnectionPool] = {
-    val poolId = new PoolId(setup, PoolId.newUniquePool)
+    val poolId = new PoolId(setup, PoolId.newUniquePool())
     poolMaster.startPool(poolId)
     poolClientFlow(poolId)
   }

akka-http-core/src/main/scala/akka/http/scaladsl/model/ws/Message.scala

@@ -99,7 +99,7 @@ sealed trait BinaryMessage extends akka.http.javadsl.model.ws.BinaryMessage with
       case BinaryMessage.Streamed(binaryStream) => binaryStream
         .completionTimeout(timeout)
         .runFold(new ByteStringBuilder())((b, e) => b.append(e))
-        .map(b => b.result)(fm.executionContext)
+        .map(b => b.result())(fm.executionContext)
         .map(binary => BinaryMessage.Strict(binary))(fm.executionContext)
     }
 

akka-http-core/src/test/scala/akka/http/impl/engine/client/ConnectionPoolSpec.scala

@@ -642,7 +642,7 @@ class NewConnectionPoolSpec extends AkkaSpecWithMaterializer("""
     def mapServerSideOutboundRawBytes(bytes: ByteString): ByteString = bytes
 
     val incomingConnectionCounter = new AtomicInteger
-    val incomingConnections = TestSubscriber.manualProbe[Http.IncomingConnection]
+    val incomingConnections = TestSubscriber.manualProbe[Http.IncomingConnection]()
     val (incomingConnectionsSub, serverHostName: String, serverPort: Int) = {
       val rawBytesInjection = BidiFlow.fromFlows(
         Flow[SslTlsOutbound].collect[ByteString] { case SendBytes(x) => mapServerSideOutboundRawBytes(x) }
@@ -729,7 +729,7 @@ class NewConnectionPoolSpec extends AkkaSpecWithMaterializer("""
 
     def flowTestBench[T, Mat](poolFlow: Flow[(HttpRequest, T), (Try[HttpResponse], T), Mat]) = {
       val requestIn = TestPublisher.probe[(HttpRequest, T)]()
-      val responseOut = TestSubscriber.manualProbe[(Try[HttpResponse], T)]
+      val responseOut = TestSubscriber.manualProbe[(Try[HttpResponse], T)]()
       val hcp = Source.fromPublisher(requestIn).viaMat(poolFlow)(Keep.right).to(Sink.fromSubscriber(responseOut)).run()
       val responseOutSub = responseOut.expectSubscription()
       (requestIn, responseOut, responseOutSub, hcp)

akka-http-core/src/test/scala/akka/http/impl/engine/client/HttpsProxyGraphStageSpec.scala

@@ -124,7 +124,7 @@ class HttpsProxyGraphStageSpec extends AkkaSpecWithMaterializer {
 
         flowOutProbe.sendNext(ByteString("HTTP/1.0 501 Some Error\r\n\r\n"))
 
-        sink.expectError match {
+        sink.expectError() match {
           case _: ProxyConnectionFailedException =>
           case e =>
             fail(s"should be ProxyConnectionFailedException, caught ${e.getClass.getName} instead")

akka-http-core/src/test/scala/akka/http/impl/engine/client/LowLevelOutgoingConnectionSpec.scala

@@ -279,7 +279,7 @@ class LowLevelOutgoingConnectionSpec extends AkkaSpecWithMaterializer with Insid
 
       inside(expectResponse()) {
         case HttpResponse(StatusCodes.OK, _, HttpEntity.Chunked(_, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           // but only one consumed by server
           data.take(1).to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()

akka-http-core/src/test/scala/akka/http/impl/engine/client/PrepareResponseSpec.scala

@@ -49,7 +49,7 @@ class PrepareResponseSpec extends AkkaSpec {
       implicit val mat = ActorMaterializer()
 
       val inProbe = TestPublisher.manualProbe[ParserOutput.ResponseOutput]()
-      val responseProbe = TestSubscriber.manualProbe[HttpResponse]
+      val responseProbe = TestSubscriber.manualProbe[HttpResponse]()
 
       Source.fromPublisher(inProbe)
         .via(new PrepareResponse(parserSettings))
@@ -94,7 +94,7 @@ class PrepareResponseSpec extends AkkaSpec {
       implicit val mat = ActorMaterializer()
 
       val inProbe = TestPublisher.manualProbe[ParserOutput.ResponseOutput]()
-      val responseProbe = TestSubscriber.manualProbe[HttpResponse]
+      val responseProbe = TestSubscriber.manualProbe[HttpResponse]()
 
       Source.fromPublisher(inProbe)
         .via(new PrepareResponse(parserSettings))
@@ -130,7 +130,7 @@ class PrepareResponseSpec extends AkkaSpec {
       implicit val mat = ActorMaterializer()
 
       val inProbe = TestPublisher.manualProbe[ParserOutput.ResponseOutput]()
-      val responseProbe = TestSubscriber.manualProbe[HttpResponse]
+      val responseProbe = TestSubscriber.manualProbe[HttpResponse]()
 
       Source.fromPublisher(inProbe)
         .via(new PrepareResponse(parserSettings))
@@ -171,7 +171,7 @@ class PrepareResponseSpec extends AkkaSpec {
       implicit val mat = ActorMaterializer()
 
       val inProbe = TestPublisher.manualProbe[ParserOutput.ResponseOutput]()
-      val responseProbe = TestSubscriber.manualProbe[HttpResponse]
+      val responseProbe = TestSubscriber.manualProbe[HttpResponse]()
 
       Source.fromPublisher(inProbe)
         .via(new PrepareResponse(parserSettings))
@@ -199,7 +199,7 @@ class PrepareResponseSpec extends AkkaSpec {
       implicit val mat = ActorMaterializer()
 
       val inProbe = TestPublisher.manualProbe[ParserOutput.ResponseOutput]()
-      val responseProbe = TestSubscriber.manualProbe[HttpResponse]
+      val responseProbe = TestSubscriber.manualProbe[HttpResponse]()
 
       Source.fromPublisher(inProbe)
         .via(new PrepareResponse(parserSettings))

akka-http-core/src/test/scala/akka/http/impl/engine/client/ResponseParsingMergeSpec.scala

@@ -28,7 +28,7 @@ class ResponseParsingMergeSpec extends AkkaSpec {
 
       val inBypassProbe = TestPublisher.manualProbe[OutgoingConnectionBlueprint.BypassData]()
       val inSessionBytesProbe = TestPublisher.manualProbe[SessionBytes]()
-      val responseProbe = TestSubscriber.manualProbe[List[ParserOutput.ResponseOutput]]
+      val responseProbe = TestSubscriber.manualProbe[List[ParserOutput.ResponseOutput]]()
 
       val responseParsingMerge: ResponseParsingMerge = {
         val rootParser = new HttpResponseParser(parserSettings, HttpHeaderParser(parserSettings, log))

akka-http-core/src/test/scala/akka/http/impl/engine/client/pool/SlotStateSpec.scala

@@ -31,7 +31,7 @@ class SlotStateSpec extends AkkaSpec {
     RequestContext(
       HttpRequest(
         entity = HttpEntity(ContentTypes.`application/octet-stream`, Source.single(ByteString("test")))),
-      Promise[HttpResponse], 0
+      Promise[HttpResponse](), 0
     )
 
   "The new connection pool slot state machine" should {

akka-http-core/src/test/scala/akka/http/impl/engine/parsing/HttpHeaderParserSpec.scala

@@ -207,7 +207,7 @@ abstract class HttpHeaderParserSpec(mode: String, newLine: String) extends AkkaS
     "continue parsing raw headers even if the overall cache value capacity is reached" in new TestSetup() {
       val randomHeaders = Iterator.continually {
         val name = nextRandomString(nextRandomAlphaNumChar _, nextRandomInt(4, 16))
-        val value = nextRandomString(() => nextRandomPrintableChar, nextRandomInt(4, 16))
+        val value = nextRandomString(() => nextRandomPrintableChar(), nextRandomInt(4, 16))
         RawHeader(name, value)
       }
       randomHeaders.take(300).foldLeft(0) {
@@ -239,7 +239,7 @@ abstract class HttpHeaderParserSpec(mode: String, newLine: String) extends AkkaS
 
     "continue parsing raw headers even if the header-specific cache capacity is reached" in new TestSetup() {
       val randomHeaders = Iterator.continually {
-        val value = nextRandomString(() => nextRandomPrintableChar, nextRandomInt(4, 16))
+        val value = nextRandomString(() => nextRandomPrintableChar(), nextRandomInt(4, 16))
         RawHeader("Fancy", value)
       }
       randomHeaders.take(20).foldLeft(0) {
@@ -311,7 +311,7 @@ abstract class HttpHeaderParserSpec(mode: String, newLine: String) extends AkkaS
         accept.mediaRanges.head.getParams.size should be(numKeys)
       }
 
-      BenchUtils.nanoRace(regular, colliding) should be < 3.0 // speed must be in same order of magnitude
+      BenchUtils.nanoRace(regular(), colliding()) should be < 3.0 // speed must be in same order of magnitude
     }
   }
 

akka-http-core/src/test/scala/akka/http/impl/engine/server/HttpServerSpec.scala

@@ -71,7 +71,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Default(_, 12, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ByteString]
+          val dataProbe = TestSubscriber.manualProbe[ByteString]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -121,7 +121,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Chunked(_, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -177,7 +177,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Default(_, 12, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ByteString]
+          val dataProbe = TestSubscriber.manualProbe[ByteString]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -202,7 +202,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Chunked(_, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -255,7 +255,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Default(_, 12, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ByteString]
+          val dataProbe = TestSubscriber.manualProbe[ByteString]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -295,7 +295,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Chunked(_, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -334,7 +334,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Default(_, 12, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ByteString]
+          val dataProbe = TestSubscriber.manualProbe[ByteString]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -358,7 +358,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Chunked(_, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -390,7 +390,7 @@ class HttpServerSpec extends AkkaSpec(
 
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Chunked(_, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           // but only one consumed by server
           data.take(1).to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
@@ -432,7 +432,7 @@ class HttpServerSpec extends AkkaSpec(
              |abcdef""")
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Default(_, 12, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ByteString]
+          val dataProbe = TestSubscriber.manualProbe[ByteString]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -454,7 +454,7 @@ class HttpServerSpec extends AkkaSpec(
              |""")
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, HttpEntity.Chunked(_, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val sub = dataProbe.expectSubscription()
           sub.request(10)
@@ -617,7 +617,7 @@ class HttpServerSpec extends AkkaSpec(
              |""")
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, Default(ContentType(`application/octet-stream`, None), 16, data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ByteString]
+          val dataProbe = TestSubscriber.manualProbe[ByteString]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val dataSub = dataProbe.expectSubscription()
           netOut.expectNoBytes(50.millis.dilated)
@@ -657,7 +657,7 @@ class HttpServerSpec extends AkkaSpec(
              |""")
       inside(expectRequest()) {
         case HttpRequest(POST, _, _, Chunked(ContentType(`application/octet-stream`, None), data), _) =>
-          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]
+          val dataProbe = TestSubscriber.manualProbe[ChunkStreamPart]()
           data.to(Sink.fromSubscriber(dataProbe)).run()
           val dataSub = dataProbe.expectSubscription()
           netOut.expectNoBytes(50.millis.dilated)

akka-http-core/src/test/scala/akka/http/impl/engine/server/HttpServerTestSetupBase.scala

@@ -23,7 +23,7 @@ abstract class HttpServerTestSetupBase {
   implicit def system: ActorSystem
   implicit def materializer: Materializer
 
-  val requests = TestSubscriber.probe[HttpRequest]
+  val requests = TestSubscriber.probe[HttpRequest]()
   val responses = TestPublisher.probe[HttpResponse]()
 
   def settings = ServerSettings(system)

akka-http-core/src/test/scala/akka/http/impl/engine/ws/MessageSpec.scala

@@ -983,7 +983,7 @@ class MessageSpec extends AkkaSpecWithMaterializer with Eventually {
 
     val netIn = TestPublisher.probe[ByteString]()
     val netOut = ByteStringSinkProbe()
-    val messageIn = TestSubscriber.probe[Message]
+    val messageIn = TestSubscriber.probe[Message]()
     val messageOut = TestPublisher.probe[Message]()
     val messageHandler: Flow[Message, Message, NotUsed] =
       Flow.fromSinkAndSource(

akka-http-core/src/test/scala/akka/http/impl/engine/ws/WebSocketIntegrationSpec.scala

@@ -78,7 +78,7 @@ class WebSocketIntegrationSpec extends AkkaSpec("akka.stream.materializer.debug.
             FlowShape(Inlet("completeOnlySwitch.in"), Outlet("completeOnlySwitch.out"))
 
           override def createLogicAndMaterializedValue(inheritedAttributes: Attributes): (GraphStageLogic, Promise[Done]) = {
-            val promise = Promise[Done]
+            val promise = Promise[Done]()
 
             val logic = new GraphStageLogic(shape) with InHandler with OutHandler {
               override def onPush(): Unit = push(shape.out, grab(shape.in))
@@ -195,7 +195,7 @@ class WebSocketIntegrationSpec extends AkkaSpec("akka.stream.materializer.debug.
     }
 
     "terminate the handler flow with an error when the connection is aborted" in Utils.assertAllStagesStopped {
-      val handlerTermination = Promise[Done]
+      val handlerTermination = Promise[Done]()
 
       val handler = Flow[Message]
         .watchTermination()(Keep.right)

akka-http-core/src/test/scala/akka/http/scaladsl/ClientServerSpec.scala

@@ -814,7 +814,7 @@ Host: example.com
 
       def handler(request: HttpRequest): Future[HttpResponse] = {
         request.entity.dataBytes.runWith(dataProbe.sink)
-        Promise[HttpResponse].future // just let it hanging until idle timeout triggers
+        Promise[HttpResponse]().future // just let it hanging until idle timeout triggers
       }
 
       val settings = ServerSettings(system).mapTimeouts(_.withIdleTimeout(1.second))
@@ -846,7 +846,7 @@ Host: example.com
     val (connSource, binding: Future[ServerBinding]) = {
       val settings = configOverrides.toOption.fold(ServerSettings(system))(ServerSettings(_))
       val connections = Http().bind(hostname, port, settings = settings)
-      val probe = TestSubscriber.manualProbe[Http.IncomingConnection]
+      val probe = TestSubscriber.manualProbe[Http.IncomingConnection]()
       val binding = connections.to(Sink.fromSubscriber(probe)).run()
       (probe, binding)
     }

akka-http-core/src/test/scala/akka/http/scaladsl/GracefulTerminationSpec.scala

@@ -109,7 +109,7 @@ class GracefulTerminationSpec
     "fail close delimited response streams" ignore new TestSetup {
       val clientSystem = ActorSystem("client")
       val r1 =
-        Http()(clientSystem).singleRequest(nextRequest, connectionContext = clientConnectionContext, settings = basePoolSettings)
+        Http()(clientSystem).singleRequest(nextRequest(), connectionContext = clientConnectionContext, settings = basePoolSettings)
 
       // reply with an infinite entity stream
       val chunks = Source

akka-http-core/src/test/scala/akka/http/scaladsl/model/HttpEntitySpec.scala

@@ -155,7 +155,7 @@ class HttpEntitySpec extends AkkaSpecWithMaterializer {
       }
       "Chunked with LastChunk with trailer header keep header chunk" in {
         val entity = Chunked(tpe, source(Chunk(abc), Chunk(fgh), Chunk(ijk), LastChunk("", RawHeader("Foo", "pip apo") :: Nil)))
-        val transformed = entity.transformDataBytes(duplicateBytesTransformer())
+        val transformed = entity.transformDataBytes(duplicateBytesTransformer)
         val parts = transformed.chunks.runWith(Sink.seq).awaitResult(100.millis)
 
         parts.map(_.data).reduce(_ ++ _) shouldEqual doubleChars("abcfghijk") ++ trailer
@@ -281,7 +281,7 @@ class HttpEntitySpec extends AkkaSpecWithMaterializer {
         strict.toString + " == " + expectedRendering)
     }
 
-  def duplicateBytesTransformer(): Flow[ByteString, ByteString, NotUsed] =
+  def duplicateBytesTransformer: Flow[ByteString, ByteString, NotUsed] =
     Flow[ByteString].via(StreamUtils.byteStringTransformer(doubleChars, () => trailer))
 
   def trailer: ByteString = ByteString("--dup")