diff --git a/internal/util-complete/src/test/scala/ParserTest.scala b/internal/util-complete/src/test/scala/ParserTest.scala
index 2db039b43..2bc1688aa 100644
--- a/internal/util-complete/src/test/scala/ParserTest.scala
+++ b/internal/util-complete/src/test/scala/ParserTest.scala
@@ -21,6 +21,7 @@ object JLineTest {
   val five = (num ~ token("+" | "-") ~ num) <~ token('=') flatMap {
     case a ~ "+" ~ b => token((a + b).toString)
     case a ~ "-" ~ b => token((a - b).toString)
+    case _           => failure("Unexpected pattern")
   }
 
   val parsers = Map("1" -> one, "2" -> two, "3" -> three, "4" -> four, "5" -> five)
diff --git a/main-actions/src/main/scala/sbt/Pkg.scala b/main-actions/src/main/scala/sbt/Pkg.scala
index 0c4146abc..96564b8e4 100644
--- a/main-actions/src/main/scala/sbt/Pkg.scala
+++ b/main-actions/src/main/scala/sbt/Pkg.scala
@@ -22,7 +22,6 @@ import sjsonnew.{
   LNil,
   Unbuilder,
   deserializationError,
-  flatUnionFormat4
 }
 
 import sbt.util.Logger
diff --git a/main-settings/src/test/scala/sbt/TupleSyntaxTest.scala b/main-settings/src/test/scala/sbt/TupleSyntaxTest.scala
index ff727b92b..7b7d4e0d0 100644
--- a/main-settings/src/test/scala/sbt/TupleSyntaxTest.scala
+++ b/main-settings/src/test/scala/sbt/TupleSyntaxTest.scala
@@ -9,7 +9,6 @@
 package sbt.test
 
 import sbt._
-import sbt.Def.Initialize
 
 object TupleSyntaxTest:
   def t1[A](a: SettingKey[A], b: TaskKey[A], c: Def.Initialize[A], d: Def.Initialize[Task[A]]) = {
diff --git a/main-settings/src/test/scala/sbt/std/UsageTest.scala b/main-settings/src/test/scala/sbt/std/UsageTest.scala
index 4aea6ccdc..b9a7ab6ca 100644
--- a/main-settings/src/test/scala/sbt/std/UsageTest.scala
+++ b/main-settings/src/test/scala/sbt/std/UsageTest.scala
@@ -32,7 +32,6 @@ end UseTask
 object Assign {
   import java.io.File
 
-  import sbt.std.FullInstance.given
   import Def.{
     Initialize,
     inputKey,
diff --git a/main/src/main/scala/sbt/Main.scala b/main/src/main/scala/sbt/Main.scala
index 488c2a7f0..7393a55b6 100644
--- a/main/src/main/scala/sbt/Main.scala
+++ b/main/src/main/scala/sbt/Main.scala
@@ -16,12 +16,9 @@ import java.util.Properties
 import java.util.concurrent.ForkJoinPool
 import java.util.concurrent.atomic.AtomicBoolean
 
-import sbt.BasicCommandStrings.{ JavaClient, Shell, Shutdown, TemplateCommand }
 import sbt.Project.LoadAction
 import sbt.ProjectExtra.*
-import sbt.internal.EvalImports
 import sbt.internal.Aggregation.AnyKeys
-import sbt.internal.CommandStrings.BootCommand
 import sbt.internal._
 import sbt.internal.client.BspClient
 import sbt.internal.inc.ScalaInstance
@@ -63,7 +60,7 @@ private[sbt] object xMain:
 
   private[sbt] def run(configuration: xsbti.AppConfiguration): xsbti.MainResult = boundary {
     try {
-      import BasicCommandStrings.{ DashDashClient, DashDashServer, runEarly }
+      import BasicCommandStrings.{ JavaClient, DashDashClient, DashDashServer, runEarly }
       import BasicCommands.early
       import BuiltinCommands.defaults
       import sbt.internal.CommandStrings.{ BootCommand, DefaultsCommand, InitCommand }
diff --git a/main/src/main/scala/sbt/ScopeFilter.scala b/main/src/main/scala/sbt/ScopeFilter.scala
index c6d9a9756..08f78d390 100644
--- a/main/src/main/scala/sbt/ScopeFilter.scala
+++ b/main/src/main/scala/sbt/ScopeFilter.scala
@@ -13,7 +13,6 @@ import sbt.internal.util.{ AttributeKey, Dag }
 import sbt.librarymanagement.{ ConfigRef, Configuration }
 import sbt.internal.util.Types.const
 import Def.Initialize
-import sbt.Project.inScope
 import java.net.URI
 
 sealed abstract class ScopeFilter { self =>
diff --git a/main/src/main/scala/sbt/internal/Continuous.scala b/main/src/main/scala/sbt/internal/Continuous.scala
index bfd03bc91..fb0eecbe1 100644
--- a/main/src/main/scala/sbt/internal/Continuous.scala
+++ b/main/src/main/scala/sbt/internal/Continuous.scala
@@ -31,7 +31,7 @@ import sbt.internal.io.WatchState
 import sbt.internal.nio._
 import sbt.internal.ui.UITask
 import sbt.internal.util.JoinThread._
-import sbt.internal.util.complete.DefaultParsers.{ Space, matched }
+import sbt.internal.util.complete.DefaultParsers.Space
 import sbt.internal.util.complete.Parser._
 import sbt.internal.util.complete.{ Parser, Parsers }
 import sbt.internal.util._
diff --git a/main/src/main/scala/sbt/internal/IncrementalTest.scala b/main/src/main/scala/sbt/internal/IncrementalTest.scala
index 180333b20..a9735acbf 100644
--- a/main/src/main/scala/sbt/internal/IncrementalTest.scala
+++ b/main/src/main/scala/sbt/internal/IncrementalTest.scala
@@ -11,14 +11,13 @@ package internal
 
 import java.io.File
 import java.util.concurrent.ConcurrentHashMap
-import Keys.{ test, fileConverter, fullClasspath, streams }
+import Keys.{ fileConverter, fullClasspath, streams }
 import sbt.Def.Initialize
 import sbt.internal.inc.Analysis
 import sbt.internal.util.Attributed
 import sbt.internal.util.Types.const
 import sbt.io.{ GlobFilter, IO, NameFilter }
 import sbt.protocol.testing.TestResult
-import sbt.SlashSyntax0.*
 import sbt.util.{ ActionCache, BuildWideCacheConfiguration, CacheLevelTag, Digest }
 import sbt.util.CacheImplicits.given
 import scala.collection.concurrent
diff --git a/main/src/main/scala/sbt/internal/LintUnused.scala b/main/src/main/scala/sbt/internal/LintUnused.scala
index 745b719d6..e78ec6854 100644
--- a/main/src/main/scala/sbt/internal/LintUnused.scala
+++ b/main/src/main/scala/sbt/internal/LintUnused.scala
@@ -10,7 +10,6 @@ package sbt
 package internal
 
 import Keys._
-import Def.{ Setting, ScopedKey }
 import sbt.internal.util.{ FilePosition, NoPosition, SourcePosition }
 import java.io.File
 import ProjectExtra.{ extract, scopedKeyData }
diff --git a/main/src/main/scala/sbt/internal/Load.scala b/main/src/main/scala/sbt/internal/Load.scala
index b9a66cdb6..c2b16d0b2 100755
--- a/main/src/main/scala/sbt/internal/Load.scala
+++ b/main/src/main/scala/sbt/internal/Load.scala
@@ -23,7 +23,7 @@ import sbt.internal.util.Attributed.data
 import sbt.internal.util.Types.const
 import sbt.internal.util.{ Attributed, Settings }
 import sbt.internal.server.BuildServerEvalReporter
-import sbt.io.{ GlobFilter, IO, Path }
+import sbt.io.{ GlobFilter, IO }
 import sbt.librarymanagement.ivy.{ InlineIvyConfiguration, IvyDependencyResolution, IvyPaths }
 import sbt.librarymanagement.{ Configuration, Configurations, Resolver }
 import sbt.nio.Settings
diff --git a/main/src/main/scala/sbt/internal/server/BuildServerProtocol.scala b/main/src/main/scala/sbt/internal/server/BuildServerProtocol.scala
index c43d6bc0b..ed9f338a4 100644
--- a/main/src/main/scala/sbt/internal/server/BuildServerProtocol.scala
+++ b/main/src/main/scala/sbt/internal/server/BuildServerProtocol.scala
@@ -15,7 +15,6 @@ import sbt.BuildExtra.*
 import sbt.BuildPaths.{ configurationSources, projectStandard }
 import sbt.Def._
 import sbt.Keys._
-import sbt.Project._
 import sbt.ProjectExtra.*
 import sbt.ScopeFilter.Make._
 import sbt.Scoped.richTaskSeq
diff --git a/main/src/main/scala/sbt/internal/server/NetworkChannel.scala b/main/src/main/scala/sbt/internal/server/NetworkChannel.scala
index 6af553be7..d6abd1aec 100644
--- a/main/src/main/scala/sbt/internal/server/NetworkChannel.scala
+++ b/main/src/main/scala/sbt/internal/server/NetworkChannel.scala
@@ -562,7 +562,6 @@ final class NetworkChannel(
   override def shutdown(): Unit = {
     shutdown(true)
   }
-  import sjsonnew.BasicJsonProtocol.BooleanJsonFormat
 
   override def shutdown(logShutdown: Boolean): Unit =
     shutdown(logShutdown, remainingCommands = None)
diff --git a/main/src/main/scala/sbt/plugins/DependencyTreeSettings.scala b/main/src/main/scala/sbt/plugins/DependencyTreeSettings.scala
index d367cc57c..6d3bee3b3 100644
--- a/main/src/main/scala/sbt/plugins/DependencyTreeSettings.scala
+++ b/main/src/main/scala/sbt/plugins/DependencyTreeSettings.scala
@@ -13,7 +13,6 @@ import java.io.File
 
 import sbt.Def._
 import sbt.Keys._
-import sbt.Project._
 import sbt.ProjectExtra.*
 import sbt.internal.graph._
 import sbt.internal.graph.backend.SbtUpdateReport
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index cd886319e..34f87b675 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -6,7 +6,7 @@ object Dependencies {
   // WARNING: Please Scala update versions in PluginCross.scala too
   val scala212 = "2.12.20"
   val scala213 = "2.13.12"
-  val scala3 = "3.3.1"
+  val scala3 = "3.3.4"
   val checkPluginCross = settingKey[Unit]("Make sure scalaVersion match up")
   val baseScalaVersion = scala3
   def nightlyVersion: Option[String] =
diff --git a/server-test/src/test/scala/testpkg/BuildServerTest.scala b/server-test/src/test/scala/testpkg/BuildServerTest.scala
index c32b78939..7952e21b8 100644
--- a/server-test/src/test/scala/testpkg/BuildServerTest.scala
+++ b/server-test/src/test/scala/testpkg/BuildServerTest.scala
@@ -93,7 +93,7 @@ class BuildServerTest extends AbstractServerTest {
       "project/src/main/scala-3",
       s"project/src/main/scala-sbt-${TestProperties.version}",
       "project/src/main/scala/",
-      "target/out/jvm/scala-3.3.1/buildserver-build/src_managed/main"
+      "target/out/jvm/scala-3.3.4/buildserver-build/src_managed/main"
     ).map(rel => new File(svr.baseDirectory.getAbsoluteFile, rel).toURI).sorted
     assert(sources == expectedSources)
   }
diff --git a/util-collection/src/main/scala/sbt/internal/util/INode.scala b/util-collection/src/main/scala/sbt/internal/util/INode.scala
index c870ea1ab..3ae954a43 100644
--- a/util-collection/src/main/scala/sbt/internal/util/INode.scala
+++ b/util-collection/src/main/scala/sbt/internal/util/INode.scala
@@ -9,8 +9,9 @@
 package sbt.internal.util
 
 import java.lang.Runnable
-import java.util.concurrent.{ atomic, Executor, LinkedBlockingQueue }
+import java.util.concurrent.{ Executor, LinkedBlockingQueue, atomic }
 import atomic.{ AtomicBoolean, AtomicInteger }
+import scala.annotation.nowarn
 
 enum EvaluationState:
   case New
@@ -35,6 +36,7 @@ abstract class EvaluateSettings[ScopeType]:
   private def getStatic[A](key: ScopedKey[A]): INode[A] =
     static.get(key).getOrElse { sys.error("Illegal reference to key " + key) }
 
+  @nowarn
   private val transform: [A] => Initialize[A] => INode[A] = [A] =>
     (fa: Initialize[A]) =>
       fa match