clear warnings in http-core

http-core/src/main/scala/org/apache/pekko/http/scaladsl/model/HttpEntity.scala

@@ -646,7 +646,7 @@ object HttpEntity {
         private var maxBytes = -1L
         private var bytesLeft = Long.MaxValue
 
-        @nowarn("msg=deprecated") // Attributes.getFirst is deprecated, but we need to use it here
+        @nowarn("msg=getFirst in class Attributes is deprecated") // there's no valid alternative right now
         override def preStart(): Unit = {
           _attributes.getFirst[SizeLimit] match {
             case Some(limit: SizeLimit) if limit.isDisabled =>

http-core/src/test/scala/org/apache/pekko/http/impl/engine/ws/WSClientAutobahnTest.scala

@@ -48,7 +48,7 @@ object WSClientAutobahnTest extends App {
     s"ws://localhost:9001/updateReports?agent=$agent"
 
   def runCase(caseIndex: Int, agent: String = Agent): Future[CaseStatus] =
-    runWs(runCaseUri(caseIndex, agent), echo).recover { case _ => () }.flatMap { _ =>
+    runWs(runCaseUri(caseIndex, agent), echo).recover { case _ => (): Any }.flatMap { _ =>
       getCaseStatus(caseIndex, agent)
     }
 

http-core/src/test/scala/org/apache/pekko/http/impl/model/parser/HttpHeaderSpec.scala

@@ -20,7 +20,6 @@ import scala.collection.immutable.Seq
 import org.apache.pekko
 import pekko.http.scaladsl.settings.ParserSettings.CookieParsingMode
 import pekko.http.impl.model.parser.HeaderParser.Settings
-import org.scalatest.matchers.{ MatchResult, Matcher }
 import pekko.http.impl.util._
 import pekko.http.scaladsl.model.{ HttpHeader, _ }
 import pekko.http.scaladsl.model.MediaRanges._
@@ -59,7 +58,8 @@ class HttpHeaderSpec extends AnyFreeSpec with Matchers {
           MediaRange.custom("text", Map("foo" -> "bar")),
           MediaType.customBinary("custom", "custom", MediaType.Compressible, params = Map("bar" -> "b>az")))
       "Accept: application/*+xml; version=2" =!=
-        Accept(MediaType.customBinary("application", "*+xml", MediaType.Compressible, params = Map("version" -> "2")))
+        Accept(MediaType.customBinary("application", "*+xml", MediaType.Compressible,
+          params = Map("version" -> "2")): MediaRange)
     }
 
     "Accept-Charset" in {

http-core/src/test/scala/org/apache/pekko/http/scaladsl/settings/ConnectionPoolSettingsSpec.scala

@@ -13,9 +13,6 @@
 
 package org.apache.pekko.http.scaladsl.settings
 
-import scala.util.Failure
-import scala.util.Success
-import scala.util.Try
 import org.apache.pekko
 import pekko.testkit.PekkoSpec
 import pekko.http.scaladsl.model.headers.`User-Agent`
@@ -161,11 +158,6 @@ class ConnectionPoolSettingsSpec extends PekkoSpec {
       settings.forHost("akka.com").minConnections shouldEqual 2
       settings.minConnections shouldEqual 2
     }
-
-    def expectError(configString: String): String = Try(config(configString)) match {
-      case Failure(cause) => cause.getMessage
-      case Success(_)     => fail("Expected a failure when max-open-requests is not a power of 2")
-    }
   }
 
   def config(configString: String): ConnectionPoolSettings =

project/Common.scala

@@ -35,6 +35,9 @@ object Common extends AutoPlugin {
       // verbosely. So, opt out of those in general.
       "-Wconf:cat=other-match-analysis&msg=match may not be exhaustive:s")).value,
     scalacOptions ++= onlyOnScala3(Seq("-Wconf:cat=deprecation:s")).value,
+    Test / scalacOptions ++= Seq(
+      // we sometimes use pattern definitions in tests just for the side-effects and don't care about the extra member
+      "-Wconf:msg=Pattern definition introduces Unit-valued member:s"),
     javacOptions ++=
       Seq("-encoding", "UTF-8", "--release", javacTarget),
     mimaReportSignatureProblems := true,