diff --git a/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala b/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala
index 4aa859018..c55aabac3 100644
--- a/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala
+++ b/buildfile/src/main/scala/sbt/internal/EvaluateConfigurations.scala
@@ -9,19 +9,12 @@
 package sbt
 package internal
 
-import sbt.internal.util.{
-  AttributeEntry,
-  AttributeKey,
-  LineRange,
-  MessageOnlyException,
-  RangePosition,
-  Settings
-}
+import sbt.internal.util.{ AttributeKey, LineRange, MessageOnlyException, RangePosition }
 
 import java.io.File
 import java.nio.file.Path
 import sbt.internal.util.complete.DefaultParsers.validID
-import Def.{ ScopedKey, Setting }
+import Def.{ ScopedKey, Setting, Settings }
 import Scope.GlobalScope
 import sbt.SlashSyntax0.given
 import sbt.internal.parser.SbtParser
@@ -351,17 +344,6 @@ object BuildUtilLite:
 end BuildUtilLite
 
 object Index {
-  def taskToKeyMap(data: Settings[Scope]): Map[Task[?], ScopedKey[Task[?]]] = {
-
-    val pairs = data.scopes flatMap (scope =>
-      data.data(scope).entries collect { case AttributeEntry(key, value: Task[_]) =>
-        (value, ScopedKey(scope, key.asInstanceOf[AttributeKey[Task[?]]]))
-      }
-    )
-
-    pairs.toMap[Task[?], ScopedKey[Task[?]]]
-  }
-
   def allKeys(settings: Seq[Setting[?]]): Set[ScopedKey[?]] = {
     val result = new java.util.HashSet[ScopedKey[?]]
     settings.foreach { s =>
@@ -372,9 +354,6 @@ object Index {
     result.asScala.toSet
   }
 
-  def attributeKeys(settings: Settings[Scope]): Set[AttributeKey[?]] =
-    settings.data.values.flatMap(_.keys).toSet[AttributeKey[?]]
-
   def stringToKeyMap(settings: Set[AttributeKey[?]]): Map[String, AttributeKey[?]] =
     stringToKeyMap0(settings)(_.label)
 
@@ -396,19 +375,17 @@ object Index {
 
   private type TriggerMap = collection.mutable.HashMap[TaskId[?], Seq[TaskId[?]]]
 
-  def triggers(ss: Settings[Scope]): Triggers = {
+  def triggers(ss: Settings): Triggers = {
     val runBefore = new TriggerMap
     val triggeredBy = new TriggerMap
-    for
-      a <- ss.data.values
-      case AttributeEntry(_, base: Task[?]) <- a.entries
-    do
+    ss.values.collect { case base: Task[?] =>
       def update(map: TriggerMap, key: AttributeKey[Seq[Task[?]]]): Unit =
-        base.info.attributes.get(key).getOrElse(Seq.empty).foreach { task =>
+        base.getOrElse(key, Seq.empty).foreach { task =>
           map(task) = base +: map.getOrElse(task, Nil)
         }
       update(runBefore, Def.runBefore)
       update(triggeredBy, Def.triggeredBy)
+    }
     val onComplete = (GlobalScope / Def.onComplete).get(ss).getOrElse(() => ())
     new Triggers(runBefore, triggeredBy, map => { onComplete(); map })
   }
diff --git a/main-actions/src/main/scala/sbt/Tests.scala b/main-actions/src/main/scala/sbt/Tests.scala
index 14e6c4ee1..d1051be52 100644
--- a/main-actions/src/main/scala/sbt/Tests.scala
+++ b/main-actions/src/main/scala/sbt/Tests.scala
@@ -463,10 +463,7 @@ object Tests {
       fun: TestFunction,
       tags: Seq[(Tag, Int)]
   ): Task[Map[String, SuiteResult]] = {
-    val base = Task[(String, (SuiteResult, Seq[TestTask]))](
-      Info[(String, (SuiteResult, Seq[TestTask]))]().setName(name),
-      Action.Pure(() => (name, fun.apply()), `inline` = false)
-    )
+    val base = Task(Action.Pure(() => (name, fun.apply()), `inline` = false)).setName(name)
     val taggedBase = base.tagw(tags*).tag(fun.tags.map(ConcurrentRestrictions.Tag(_))*)
     taggedBase flatMap { case (name, (result, nested)) =>
       val nestedRunnables = createNestedRunnables(loader, fun, nested)
diff --git a/main-settings/src/main/scala/sbt/Def.scala b/main-settings/src/main/scala/sbt/Def.scala
index c4d48256b..3d81fe1e3 100644
--- a/main-settings/src/main/scala/sbt/Def.scala
+++ b/main-settings/src/main/scala/sbt/Def.scala
@@ -54,7 +54,8 @@ trait BuildSyntax:
 end BuildSyntax
 
 /** A concrete settings system that uses `sbt.Scope` for the scope type. */
-object Def extends BuildSyntax with Init[Scope] with InitializeImplicits:
+object Def extends BuildSyntax with Init with InitializeImplicits:
+  type ScopeType = Scope
   type Classpath = Seq[Attributed[HashedVirtualFileRef]]
 
   def settings(ss: SettingsDefinition*): Seq[Setting[?]] = ss.flatMap(_.settings)
@@ -457,11 +458,11 @@ object Def extends BuildSyntax with Init[Scope] with InitializeImplicits:
         sys.error(s"Dummy task '$name' did not get converted to a full task.")
       )
       .named(name)
-    base.copy(info = base.info.set(isDummyTask, true))
+    base.set(isDummyTask, true)
   }
 
   private[sbt] def isDummy(t: Task[?]): Boolean =
-    t.info.attributes.get(isDummyTask) getOrElse false
+    t.get(isDummyTask).getOrElse(false)
 end Def
 
 sealed trait InitializeImplicits { self: Def.type =>
diff --git a/main-settings/src/main/scala/sbt/Previous.scala b/main-settings/src/main/scala/sbt/Previous.scala
index cfe289c8c..d11ee2547 100644
--- a/main-settings/src/main/scala/sbt/Previous.scala
+++ b/main-settings/src/main/scala/sbt/Previous.scala
@@ -127,7 +127,7 @@ object Previous {
     val successfulTaskResults = (
       for
         case results.TPair(task: Task[?], Result.Value(v)) <- results.toTypedSeq
-        key <- task.info.attributes.get(Def.taskDefinitionKey).asInstanceOf[Option[AnyTaskKey]]
+        key <- task.get(Def.taskDefinitionKey).asInstanceOf[Option[AnyTaskKey]]
       yield key -> v
     ).toMap
     // We then traverse the successful results and look up all of the referenced values for
diff --git a/main-settings/src/main/scala/sbt/Project.scala b/main-settings/src/main/scala/sbt/Project.scala
index 73f455378..cfca795f4 100644
--- a/main-settings/src/main/scala/sbt/Project.scala
+++ b/main-settings/src/main/scala/sbt/Project.scala
@@ -334,7 +334,7 @@ object Project:
     ScopedKey(Scope.fillTaskAxis(scoped.scope, scoped.key), scoped.key)
 
   def mapScope(f: Scope => Scope): [a] => ScopedKey[a] => ScopedKey[a] =
-    [a] => (k: ScopedKey[a]) => ScopedKey(f(k.scope), k.key)
+    [a] => (k: ScopedKey[a]) => k.copy(scope = f(k.scope))
 
   def transform(g: Scope => Scope, ss: Seq[Def.Setting[?]]): Seq[Def.Setting[?]] =
     // We use caching to avoid creating new Scope instances too many times
@@ -361,7 +361,10 @@ object Project:
     Project.transform(Scope.replaceThis(scope), ss)
 
   private[sbt] def inScope[A](scope: Scope, i: Initialize[A]): Initialize[A] =
-    i.mapReferenced(Project.mapScope(Scope.replaceThis(scope)))
+    i.mapReferenced(replaceThis(scope))
+
+  private[sbt] def replaceThis(scope: Scope): Def.MapScoped =
+    mapScope(Scope.replaceThis(scope))
 
   /**
    * Normalize a String so that it is suitable for use as a dependency management module identifier.
diff --git a/main-settings/src/main/scala/sbt/Structure.scala b/main-settings/src/main/scala/sbt/Structure.scala
index 7986dc16d..6bf160625 100644
--- a/main-settings/src/main/scala/sbt/Structure.scala
+++ b/main-settings/src/main/scala/sbt/Structure.scala
@@ -11,7 +11,7 @@ package sbt
 import scala.annotation.targetName
 
 import sbt.internal.util.Types.*
-import sbt.internal.util.{ AttributeKey, KeyTag, Settings, SourcePosition }
+import sbt.internal.util.{ AttributeKey, KeyTag, SourcePosition }
 import sbt.internal.util.TupleMapExtension.*
 import sbt.util.OptJsonWriter
 import sbt.ConcurrentRestrictions.Tag
@@ -303,8 +303,7 @@ object Scoped:
       setting(scopedKey, app, source)
 
     /** From the given `Settings`, extract the value bound to this key. */
-    final def get(settings: Settings[Scope]): Option[A1] =
-      settings.get(scopedKey.scope, scopedKey.key)
+    final def get(settings: Def.Settings): Option[A1] = settings.get(scopedKey)
 
     /**
      * Creates an [[Def.Initialize]] with value `scala.None` if there was no previous definition of this key,
@@ -385,7 +384,7 @@ object Scoped:
       ): Initialize[Task[A1]] =
         Initialize
           .joinAny[Task](coerceToAnyTaskSeq(tasks))
-          .zipWith(init)((ts, i) => i.copy(info = i.info.set(key, ts)))
+          .zipWith(init)((ts, i) => i.set(key, ts))
 
     extension [A1](init: Initialize[InputTask[A1]])
       @targetName("onTaskInitializeInputTask")
@@ -460,7 +459,7 @@ object Scoped:
 
     def toSettingKey: SettingKey[Task[A1]] = scopedSetting(scope, key)
 
-    def get(settings: Settings[Scope]): Option[Task[A1]] = settings.get(scope, key)
+    def get(settings: Def.Settings): Option[Task[A1]] = settings.get(scopedKey)
 
     /**
      * Creates an [[Def.Initialize]] with value `scala.None` if there was no previous definition of this key,
diff --git a/main-settings/src/main/scala/sbt/std/Instances.scala b/main-settings/src/main/scala/sbt/std/Instances.scala
index b6ca657d1..1bbd22023 100644
--- a/main-settings/src/main/scala/sbt/std/Instances.scala
+++ b/main-settings/src/main/scala/sbt/std/Instances.scala
@@ -47,7 +47,7 @@ end ParserInstance
 
 /** Composes the Task and Initialize Instances to provide an Instance for [A1] Initialize[Task[A1]]. */
 object FullInstance:
-  type SS = sbt.internal.util.Settings[Scope]
+  type SS = Def.Settings
   val settingsData = TaskKey[SS](
     "settings-data",
     "Provides access to the project data for the build.",
diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 54963f387..056da3523 100644
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -4001,14 +4001,15 @@ object Classpaths {
         try {
           val extracted = Project.extract(st)
           val sk = (projRef / Zero / Zero / libraryDependencies).scopedKey
-          val empty = extracted.structure.data.set(sk.scope, sk.key, Nil)
+          val empty = extracted.structure.data.set(sk, Nil)
           val settings = extracted.structure.settings filter { (s: Setting[?]) =>
             (s.key.key == libraryDependencies.key) &&
             (s.key.scope.project == Select(projRef))
           }
-          Map(settings.asInstanceOf[Seq[Setting[Seq[ModuleID]]]].flatMap { s =>
-            s.init.evaluate(empty) map { _ -> s.pos }
-          }*)
+          settings
+            .asInstanceOf[Seq[Setting[Seq[ModuleID]]]]
+            .flatMap(s => s.init.evaluate(empty).map(_ -> s.pos))
+            .toMap
         } catch {
           case NonFatal(_) => Map()
         }
@@ -4163,7 +4164,7 @@ object Classpaths {
 
   private[sbt] def depMap(
       projects: Seq[ProjectRef],
-      data: Settings[Scope],
+      data: Def.Settings,
       log: Logger
   ): Task[Map[ModuleRevisionId, ModuleDescriptor]] =
     val ivyModules = projects.flatMap { proj =>
@@ -4240,14 +4241,14 @@ object Classpaths {
   def interSort(
       projectRef: ProjectRef,
       conf: Configuration,
-      data: Settings[Scope],
+      data: Def.Settings,
       deps: BuildDependencies
   ): Seq[(ProjectRef, String)] = ClasspathImpl.interSort(projectRef, conf, data, deps)
 
   def interSortConfigurations(
       projectRef: ProjectRef,
       conf: Configuration,
-      data: Settings[Scope],
+      data: Def.Settings,
       deps: BuildDependencies
   ): Seq[(ProjectRef, ConfigRef)] =
     interSort(projectRef, conf, data, deps).map { case (projectRef, configName) =>
@@ -4291,23 +4292,23 @@ object Classpaths {
     sys.error("Configuration '" + conf + "' not defined in '" + in + "'")
   def allConfigs(conf: Configuration): Seq[Configuration] = ClasspathImpl.allConfigs(conf)
 
-  def getConfigurations(p: ResolvedReference, data: Settings[Scope]): Seq[Configuration] =
+  def getConfigurations(p: ResolvedReference, data: Def.Settings): Seq[Configuration] =
     ClasspathImpl.getConfigurations(p, data)
   def confOpt(configurations: Seq[Configuration], conf: String): Option[Configuration] =
     ClasspathImpl.confOpt(configurations, conf)
 
-  def unmanagedLibs(dep: ResolvedReference, conf: String, data: Settings[Scope]): Task[Classpath] =
+  def unmanagedLibs(dep: ResolvedReference, conf: String, data: Def.Settings): Task[Classpath] =
     ClasspathImpl.unmanagedLibs(dep, conf, data)
 
   def getClasspath(
       key: TaskKey[Classpath],
       dep: ResolvedReference,
       conf: String,
-      data: Settings[Scope]
+      data: Def.Settings
   ): Task[Classpath] =
     ClasspathImpl.getClasspath(key, dep, conf, data)
 
-  def defaultConfigurationTask(p: ResolvedReference, data: Settings[Scope]): Configuration =
+  def defaultConfigurationTask(p: ResolvedReference, data: Def.Settings): Configuration =
     (p / defaultConfiguration).get(data).flatten.getOrElse(Configurations.Default)
 
   val sbtIvySnapshots: URLRepository = Resolver.sbtIvyRepo("snapshots")
@@ -4748,7 +4749,7 @@ trait BuildExtra extends BuildCommon with DefExtra {
   def initScoped[T](sk: ScopedKey[?], i: Initialize[T]): Initialize[T] =
     initScope(fillTaskAxis(sk.scope, sk.key), i)
   def initScope[T](s: Scope, i: Initialize[T]): Initialize[T] =
-    i.mapReferenced(Project.mapScope(Scope.replaceThis(s)))
+    Project.inScope(s, i)
 
   /**
    * Disables post-compilation hook for determining tests for tab-completion (such as for 'test-only').
diff --git a/main/src/main/scala/sbt/EvaluateTask.scala b/main/src/main/scala/sbt/EvaluateTask.scala
index 326736b90..4defc40af 100644
--- a/main/src/main/scala/sbt/EvaluateTask.scala
+++ b/main/src/main/scala/sbt/EvaluateTask.scala
@@ -449,8 +449,8 @@ object EvaluateTask {
       ref: ProjectRef
   ): Option[(Task[T], NodeView)] = {
     val thisScope = Load.projectScope(ref)
-    val resolvedScope = Scope.replaceThis(thisScope)(taskKey.scope)
-    for (t <- structure.data.get(resolvedScope, taskKey.key))
+    val subScoped = Project.replaceThis(thisScope)(taskKey.scopedKey)
+    for (t <- structure.data.get(subScoped))
       yield (t, nodeView(state, streams, taskKey :: Nil))
   }
   def nodeView(
@@ -582,7 +582,7 @@ object EvaluateTask {
     Function.chain(
       results.toTypedSeq flatMap {
         case results.TPair(_, Result.Value(KeyValue(_, st: StateTransform))) => Some(st.transform)
-        case results.TPair(Task(info, _), Result.Value(v)) => info.post(v).get(transformState)
+        case results.TPair(task: Task[?], Result.Value(v)) => task.post(v).get(transformState)
         case _                                             => Nil
       }
     )
diff --git a/main/src/main/scala/sbt/Extracted.scala b/main/src/main/scala/sbt/Extracted.scala
index 4f3adc174..b560ab801 100644
--- a/main/src/main/scala/sbt/Extracted.scala
+++ b/main/src/main/scala/sbt/Extracted.scala
@@ -12,7 +12,6 @@ import sbt.internal.{ Load, BuildStructure, Act, Aggregation, SessionSettings }
 import Scope.GlobalScope
 import Def.{ ScopedKey, Setting }
 import sbt.internal.util.complete.Parser
-import sbt.internal.util.AttributeKey
 import sbt.util.Show
 import std.Transform.DummyTaskMap
 import sbt.EvaluateTask.extractedTaskConfig
@@ -34,21 +33,21 @@ final case class Extracted(
    * If the project axis is not explicitly specified, it is resolved to be the current project according to the extracted `session`.
    * Other axes are resolved to be `Zero` if they are not specified.
    */
-  def get[T](key: SettingKey[T]): T = getOrError(inCurrent(key.scope), key.key)
-  def get[T](key: TaskKey[T]): Task[T] = getOrError(inCurrent(key.scope), key.key)
+  def get[T](key: SettingKey[T]): T = getOrError(inCurrent(key.scopedKey))
+  def get[T](key: TaskKey[T]): Task[T] = getOrError(inCurrent(key.scopedKey))
 
   /**
    * Gets the value assigned to `key` in the computed settings map wrapped in Some.  If it does not exist, None is returned.
    * If the project axis is not explicitly specified, it is resolved to be the current project according to the extracted `session`.
    * Other axes are resolved to be `Zero` if they are not specified.
    */
-  def getOpt[T](key: SettingKey[T]): Option[T] = structure.data.get(inCurrent(key.scope), key.key)
+  def getOpt[T](key: SettingKey[T]): Option[T] = structure.data.get(inCurrent(key.scopedKey))
   def getOpt[T](key: TaskKey[T]): Option[Task[T]] =
-    structure.data.get(inCurrent(key.scope), key.key)
+    structure.data.get(inCurrent(key))
 
-  private def inCurrent(scope: Scope): Scope =
-    if scope.project == This then scope.rescope(currentRef)
-    else scope
+  private def inCurrent[T](key: ScopedKey[T]): ScopedKey[T] =
+    if key.scope.project == This then key.copy(scope = key.scope.rescope(currentRef))
+    else key
 
   /**
    * Runs the task specified by `key` and returns the transformed State and the resulting value of the task.
@@ -63,7 +62,7 @@ final case class Extracted(
     val config = extractedTaskConfig(this, structure, state)
     val value: Option[(State, Result[T])] =
       EvaluateTask(structure, key.scopedKey, state, currentRef, config)
-    val (newS, result) = getOrError(rkey.scope, rkey.key, value)
+    val (newS, result) = getOrError(rkey.scopedKey, value)
     (newS, EvaluateTask.processResult2(result))
   }
 
@@ -116,15 +115,15 @@ final case class Extracted(
   private def resolve[K <: Scoped.ScopingSetting[K] & Scoped](key: K): K =
     Scope.resolveScope(GlobalScope, currentRef.build, rootProject)(key.scope) / key
 
-  private def getOrError[T](scope: Scope, key: AttributeKey[?], value: Option[T])(implicit
+  private def getOrError[T](key: ScopedKey[?], value: Option[T])(implicit
       display: Show[ScopedKey[?]]
   ): T =
-    value getOrElse sys.error(display.show(ScopedKey(scope, key)) + " is undefined.")
+    value.getOrElse(sys.error(display.show(key) + " is undefined."))
 
-  private def getOrError[T](scope: Scope, key: AttributeKey[T])(implicit
+  private def getOrError[T](key: ScopedKey[T])(implicit
       display: Show[ScopedKey[?]]
   ): T =
-    getOrError(scope, key, structure.data.get(scope, key))(display)
+    getOrError(key, structure.data.get(key))(display)
 
   @deprecated(
     "This discards session settings. Migrate to appendWithSession or appendWithoutSession.",
diff --git a/main/src/main/scala/sbt/ProjectExtra.scala b/main/src/main/scala/sbt/ProjectExtra.scala
index f512f845a..d5d40ddb8 100755
--- a/main/src/main/scala/sbt/ProjectExtra.scala
+++ b/main/src/main/scala/sbt/ProjectExtra.scala
@@ -47,7 +47,7 @@ import sbt.internal.{
   SettingGraph,
   SessionSettings
 }
-import sbt.internal.util.{ AttributeKey, AttributeMap, Relation, Settings }
+import sbt.internal.util.{ AttributeKey, AttributeMap, Relation }
 import sbt.internal.util.Types.const
 import sbt.internal.server.ServerHandler
 import sbt.librarymanagement.Configuration
@@ -288,10 +288,10 @@ trait ProjectExtra extends Scoped.Syntax:
     def orIdentity[A](opt: Option[A => A]): A => A =
       opt.getOrElse(identity)
 
-    def getHook[A](key: SettingKey[A => A], data: Settings[Scope]): A => A =
+    def getHook[A](key: SettingKey[A => A], data: Def.Settings): A => A =
       orIdentity((Global / key).get(data))
 
-    def getHooks(data: Settings[Scope]): (State => State, State => State) =
+    def getHooks(data: Def.Settings): (State => State, State => State) =
       (getHook(Keys.onLoad, data), getHook(Keys.onUnload, data))
 
     def current(state: State): ProjectRef = session(state).current
@@ -373,46 +373,34 @@ trait ProjectExtra extends Scoped.Syntax:
 
     private[sbt] def scopedKeyData(
         structure: BuildStructure,
-        scope: Scope,
-        key: AttributeKey[?]
+        key: ScopedKey[?]
     ): Option[ScopedKeyData[?]] =
-      structure.data.get(scope, key) map { v =>
-        ScopedKeyData(ScopedKey(scope, key), v)
-      }
+      structure.data.getKeyValue(key).map((defining, value) => ScopedKeyData(key, defining, value))
 
-    def details(structure: BuildStructure, actual: Boolean, scope: Scope, key: AttributeKey[?])(
-        using display: Show[ScopedKey[?]]
+    def details(structure: BuildStructure, actual: Boolean, key: ScopedKey[?])(using
+        display: Show[ScopedKey[?]]
     ): String = {
-      val scoped = ScopedKey(scope, key)
+      val data = scopedKeyData(structure, key).map(_.description).getOrElse("No entry for key.")
+      val description = key.key.description match
+        case Some(desc) => s"Description:\n\t$desc\n"
+        case None       => ""
 
-      val data = scopedKeyData(structure, scope, key) map { _.description } getOrElse {
-        "No entry for key."
-      }
-      val description = key.description match {
-        case Some(desc) => "Description:\n\t" + desc + "\n"; case None => ""
-      }
-
-      val definingScope = structure.data.definingScope(scope, key)
-      val providedBy = definingScope match {
-        case Some(sc) => "Provided by:\n\t" + Scope.display(sc, key.label) + "\n"
-        case None     => ""
-      }
-      val definingScoped = definingScope match {
-        case Some(sc) => ScopedKey(sc, key)
-        case None     => scoped
-      }
+      val (definingKey, providedBy) = structure.data.definingKey(key) match
+        case Some(k) => k -> s"Provided by:\n\t${Scope.display(k.scope, key.key.label)}\n"
+        case None    => key -> ""
       val comp =
         Def.compiled(structure.settings, actual)(using
           structure.delegates,
           structure.scopeLocal,
           display
         )
-      val definedAt = comp get definingScoped map { c =>
-        Def.definedAtString(c.settings).capitalize
-      } getOrElse ""
+      val definedAt = comp
+        .get(definingKey)
+        .map(c => Def.definedAtString(c.settings).capitalize)
+        .getOrElse("")
 
       val cMap = Def.flattenLocals(comp)
-      val related = cMap.keys.filter(k => k.key == key && k.scope != scope)
+      val related = cMap.keys.filter(k => k.key == key.key && k.scope != key.scope)
       def derivedDependencies(c: ScopedKey[?]): List[ScopedKey[?]] =
         comp
           .get(c)
@@ -420,14 +408,14 @@ trait ProjectExtra extends Scoped.Syntax:
           .toList
           .flatten
 
-      val depends = cMap.get(scoped) match {
-        case Some(c) => c.dependencies.toSet; case None => Set.empty
-      }
-      val derivedDepends: Set[ScopedKey[?]] = derivedDependencies(definingScoped).toSet
+      val depends = cMap.get(key) match
+        case Some(c) => c.dependencies.toSet
+        case None    => Set.empty
+      val derivedDepends: Set[ScopedKey[?]] = derivedDependencies(definingKey).toSet
 
-      val reverse = Project.reverseDependencies(cMap, scoped)
+      val reverse = Project.reverseDependencies(cMap, key)
       val derivedReverse =
-        reverse.filter(r => derivedDependencies(r).contains(definingScoped)).toSet
+        reverse.filter(r => derivedDependencies(r).contains(definingKey)).toSet
 
       def printDepScopes(
           baseLabel: String,
@@ -460,7 +448,7 @@ trait ProjectExtra extends Scoped.Syntax:
         definedAt +
         printDepScopes("Dependencies", "derived from", depends, derivedDepends) +
         printDepScopes("Reverse dependencies", "derives", reverse, derivedReverse) +
-        printScopes("Delegates", delegates(structure, scope, key)) +
+        printScopes("Delegates", delegates(structure, key.scope, key.key)) +
         printScopes("Related", related, 10)
     }
 
diff --git a/main/src/main/scala/sbt/ScopedKeyData.scala b/main/src/main/scala/sbt/ScopedKeyData.scala
index 3cfbf3750..4c4d5a48a 100644
--- a/main/src/main/scala/sbt/ScopedKeyData.scala
+++ b/main/src/main/scala/sbt/ScopedKeyData.scala
@@ -11,16 +11,14 @@ package sbt
 import Def.ScopedKey
 import sbt.internal.util.KeyTag
 
-final case class ScopedKeyData[A](scoped: ScopedKey[A], value: Any) {
-  val key = scoped.key
-  val scope = scoped.scope
-  def typeName: String = key.tag.toString
+final case class ScopedKeyData[A](key: ScopedKey[A], definingKey: ScopedKey[A], value: Any) {
+  def typeName: String = key.key.tag.toString
   def settingValue: Option[Any] =
-    key.tag match
+    key.key.tag match
       case KeyTag.Setting(_) => Some(value)
       case _                 => None
   def description: String =
-    key.tag match
+    key.key.tag match
       case KeyTag.Task(typeArg)      => s"Task: $typeArg"
       case KeyTag.SeqTask(typeArg)   => s"Task: Seq[$typeArg]"
       case KeyTag.InputTask(typeArg) => s"Input task: $typeArg"
diff --git a/main/src/main/scala/sbt/SessionVar.scala b/main/src/main/scala/sbt/SessionVar.scala
index 40a36b587..5356bf4e7 100644
--- a/main/src/main/scala/sbt/SessionVar.scala
+++ b/main/src/main/scala/sbt/SessionVar.scala
@@ -49,20 +49,21 @@ object SessionVar {
 
   def orEmpty(opt: Option[Map]) = opt.getOrElse(emptyMap)
 
-  def transform[S](task: Task[S], f: (State, S) => State): Task[S] = {
+  def transform[S](task: Task[S], f: (State, S) => State): Task[S] =
     val g = (s: S, map: AttributeMap) => map.put(Keys.transformState, (state: State) => f(state, s))
-    task.copy(info = task.info.postTransform(g))
-  }
+    task.postTransform(g)
 
   def resolveContext[T](
       key: ScopedKey[Task[T]],
       context: Scope,
       state: State
-  ): ScopedKey[Task[T]] = {
-    val subScope = Scope.replaceThis(context)(key.scope)
-    val scope = Project.structure(state).data.definingScope(subScope, key.key) getOrElse subScope
-    ScopedKey(scope, key.key)
-  }
+  ): ScopedKey[Task[T]] =
+    val subScoped = Project.replaceThis(context)(key)
+    Project
+      .structure(state)
+      .data
+      .definingKey(subScoped)
+      .getOrElse(subScoped)
 
   def read[T](key: ScopedKey[Task[T]], state: State)(implicit f: JsonFormat[T]): Option[T] =
     Project.structure(state).streams(state).use(key) { s =>
diff --git a/main/src/main/scala/sbt/internal/AbstractTaskProgress.scala b/main/src/main/scala/sbt/internal/AbstractTaskProgress.scala
index 626f041f1..b7542670a 100644
--- a/main/src/main/scala/sbt/internal/AbstractTaskProgress.scala
+++ b/main/src/main/scala/sbt/internal/AbstractTaskProgress.scala
@@ -112,7 +112,7 @@ private[sbt] abstract class AbstractTaskExecuteProgress extends ExecuteProgress
   }
   private def taskName0(t: TaskId[?]): String = {
     def definedName(node: Task[?]): Option[String] =
-      node.info.name.orElse(TaskName.transformNode(node).map(showScopedKey.show))
+      node.name.orElse(TaskName.transformNode(node).map(showScopedKey.show))
     def inferredName(t: Task[?]): Option[String] = nameDelegate(t) map taskName
     def nameDelegate(t: Task[?]): Option[TaskId[?]] =
       Option(anonOwners.get(t)).orElse(Option(calledBy.get(t)))
diff --git a/main/src/main/scala/sbt/internal/Act.scala b/main/src/main/scala/sbt/internal/Act.scala
index c5ca91bfa..324bf6491 100644
--- a/main/src/main/scala/sbt/internal/Act.scala
+++ b/main/src/main/scala/sbt/internal/Act.scala
@@ -24,7 +24,6 @@ import sbt.internal.util.{
   AttributeMap,
   IMap,
   MessageOnlyException,
-  Settings,
   Util,
 }
 import sbt.util.Show
@@ -61,7 +60,7 @@ object Act {
       current: ProjectRef,
       defaultConfigs: Option[ResolvedReference] => Seq[String],
       keyMap: Map[String, AttributeKey[?]],
-      data: Settings[Scope]
+      data: Def.Settings
   ): Parser[ScopedKey[Any]] =
     scopedKeySelected(index, current, defaultConfigs, keyMap, data, askProject = true)
       .map(_.key.asInstanceOf[ScopedKey[Any]])
@@ -115,7 +114,7 @@ object Act {
       current: ProjectRef,
       defaultConfigs: Option[ResolvedReference] => Seq[String],
       keyMap: Map[String, AttributeKey[?]],
-      data: Settings[Scope],
+      data: Def.Settings,
       askProject: Boolean,
   ): Parser[ParsedKey] =
     scopedKeyFull(index, current, defaultConfigs, keyMap, askProject = askProject).flatMap {
@@ -197,7 +196,7 @@ object Act {
       key
     )
 
-  def select(allKeys: Seq[Parser[ParsedKey]], data: Settings[Scope])(implicit
+  def select(allKeys: Seq[Parser[ParsedKey]], data: Def.Settings)(implicit
       show: Show[ScopedKey[?]]
   ): Parser[ParsedKey] =
     seq(allKeys) flatMap { ss =>
@@ -235,10 +234,7 @@ object Act {
   def showAmbiguous(keys: Seq[ScopedKey[?]])(implicit show: Show[ScopedKey[?]]): String =
     keys.take(3).map(x => show.show(x)).mkString("", ", ", if (keys.size > 3) ", ..." else "")
 
-  def isValid(data: Settings[Scope])(parsed: ParsedKey): Boolean = {
-    val key = parsed.key
-    data.definingScope(key.scope, key.key) == Some(key.scope)
-  }
+  def isValid(data: Def.Settings)(parsed: ParsedKey): Boolean = data.contains(parsed.key)
 
   def examples(p: Parser[String], exs: Set[String], label: String): Parser[String] =
     (p !!! ("Expected " + label)).examples(exs)
@@ -571,28 +567,14 @@ object Act {
   def keyValues[T](extracted: Extracted)(keys: Seq[ScopedKey[T]]): Values[T] =
     keyValues(extracted.structure)(keys)
   def keyValues[T](structure: BuildStructure)(keys: Seq[ScopedKey[T]]): Values[T] =
-    keys.flatMap { key =>
-      getValue(structure.data, key.scope, key.key) map { value =>
-        KeyValue(key, value)
-      }
-    }
-  private def anyKeyValues(
-      structure: BuildStructure,
-      keys: Seq[ScopedKey[?]]
-  ): Seq[KeyValue[?]] =
-    keys.flatMap { key =>
-      getValue(structure.data, key.scope, key.key) map { value =>
-        KeyValue(key, value)
-      }
-    }
+    keys.flatMap(key => getValue(structure.data, key).map(KeyValue(key, _)))
 
-  private def getValue[T](
-      data: Settings[Scope],
-      scope: Scope,
-      key: AttributeKey[T]
-  ): Option[T] =
-    if (java.lang.Boolean.getBoolean("sbt.cli.nodelegation")) data.getDirect(scope, key)
-    else data.get(scope, key)
+  private def anyKeyValues(structure: BuildStructure, keys: Seq[ScopedKey[?]]): Seq[KeyValue[?]] =
+    keys.flatMap(key => getValue(structure.data, key).map(KeyValue(key, _)))
+
+  private def getValue[T](data: Def.Settings, key: ScopedKey[T]): Option[T] =
+    if (java.lang.Boolean.getBoolean("sbt.cli.nodelegation")) data.getDirect(key)
+    else data.get(key)
 
   def requireSession[T](s: State, p: => Parser[T]): Parser[T] =
     if s.get(sessionSettings).isEmpty then failure("No project loaded") else p
diff --git a/main/src/main/scala/sbt/internal/Aggregation.scala b/main/src/main/scala/sbt/internal/Aggregation.scala
index 924edc4f3..9afa960ce 100644
--- a/main/src/main/scala/sbt/internal/Aggregation.scala
+++ b/main/src/main/scala/sbt/internal/Aggregation.scala
@@ -11,7 +11,7 @@ package internal
 
 import java.text.DateFormat
 
-import sbt.Def.ScopedKey
+import sbt.Def.{ ScopedKey, Settings }
 import sbt.Keys.{ showSuccess, showTiming, timingFormat }
 import sbt.ProjectExtra.*
 import sbt.SlashSyntax0.given
@@ -157,7 +157,7 @@ object Aggregation {
   private def timingString(
       startTime: Long,
       endTime: Long,
-      data: Settings[Scope],
+      data: Settings,
       currentRef: ProjectRef,
   ): String = {
     val format = (currentRef / timingFormat).get(data) getOrElse defaultFormat
@@ -266,29 +266,40 @@ object Aggregation {
       else extra.aggregates.forward(ref)
     }
 
+  /**
+   * Compute the reverse aggregate keys of all the `keys` at once.
+   * This is more performant than computing the revere aggregate keys of each key individually
+   * because of the duplicates. One aggregate key is the aggregation of many keys.
+   */
+  def reverseAggregate[Proj](
+      keys: Set[ScopedKey[?]],
+      extra: BuildUtil[Proj],
+  ): Iterable[ScopedKey[?]] =
+    val mask = ScopeMask()
+    def recur(keys: Set[ScopedKey[?]], acc: Set[ScopedKey[?]]): Set[ScopedKey[?]] =
+      if keys.isEmpty then acc
+      else
+        val aggKeys = for
+          key <- keys
+          ref <- projectAggregates(key.scope.project.toOption, extra, reverse = true)
+          toResolve = key.scope.copy(project = Select(ref))
+          resolved = Resolve(extra, Zero, key.key, mask)(toResolve)
+          scoped = ScopedKey(resolved, key.key)
+          if !acc.contains(scoped)
+        yield scoped
+        val filteredAggKeys = aggKeys.filter(aggregationEnabled(_, extra.data))
+        // recursive because an aggregate project can be aggregated in another aggregate project
+        recur(filteredAggKeys, acc ++ filteredAggKeys)
+    recur(keys, keys)
+
   def aggregate[A1, Proj](
       key: ScopedKey[A1],
       rawMask: ScopeMask,
-      extra: BuildUtil[Proj],
-      reverse: Boolean = false
+      extra: BuildUtil[Proj]
   ): Seq[ScopedKey[A1]] =
     val mask = rawMask.copy(project = true)
     Dag.topologicalSort(key): (k) =>
-      if reverse then reverseAggregatedKeys(k, extra, mask)
-      else if aggregationEnabled(k, extra.data) then aggregatedKeys(k, extra, mask)
-      else Nil
-
-  def reverseAggregatedKeys[T](
-      key: ScopedKey[T],
-      extra: BuildUtil[?],
-      mask: ScopeMask
-  ): Seq[ScopedKey[T]] =
-    projectAggregates(key.scope.project.toOption, extra, reverse = true) flatMap { ref =>
-      val toResolve = key.scope.copy(project = Select(ref))
-      val resolved = Resolve(extra, Zero, key.key, mask)(toResolve)
-      val skey = ScopedKey(resolved, key.key)
-      if (aggregationEnabled(skey, extra.data)) skey :: Nil else Nil
-    }
+      if aggregationEnabled(k, extra.data) then aggregatedKeys(k, extra, mask) else Nil
 
   def aggregatedKeys[T](
       key: ScopedKey[T],
@@ -301,7 +312,7 @@ object Aggregation {
       ScopedKey(resolved, key.key)
     }
 
-  def aggregationEnabled(key: ScopedKey[?], data: Settings[Scope]): Boolean =
+  def aggregationEnabled(key: ScopedKey[?], data: Settings): Boolean =
     (Scope.fillTaskAxis(key.scope, key.key) / Keys.aggregate).get(data).getOrElse(true)
   private[sbt] val suppressShow =
     AttributeKey[Boolean]("suppress-aggregation-show", Int.MaxValue)
diff --git a/main/src/main/scala/sbt/internal/BuildStructure.scala b/main/src/main/scala/sbt/internal/BuildStructure.scala
index eb52c31a9..df9dc34c3 100644
--- a/main/src/main/scala/sbt/internal/BuildStructure.scala
+++ b/main/src/main/scala/sbt/internal/BuildStructure.scala
@@ -20,7 +20,7 @@ import sbt.SlashSyntax0.given
 import BuildStreams.Streams
 import sbt.io.syntax._
 import sbt.internal.inc.MappedFileConverter
-import sbt.internal.util.{ AttributeEntry, AttributeKey, AttributeMap, Attributed, Settings }
+import sbt.internal.util.{ AttributeEntry, AttributeKey, AttributeMap, Attributed }
 import sbt.internal.util.Attributed.data
 import sbt.util.Logger
 import xsbti.FileConverter
@@ -29,7 +29,7 @@ final class BuildStructure(
     val units: Map[URI, LoadedBuildUnit],
     val root: URI,
     val settings: Seq[Setting[?]],
-    val data: Settings[Scope],
+    val data: Def.Settings,
     val index: StructureIndex,
     val streams: State => Streams,
     val delegates: Scope => Seq[Scope],
@@ -71,7 +71,6 @@ final class BuildStructure(
 // information that is not original, but can be reconstructed from the rest of BuildStructure
 final class StructureIndex(
     val keyMap: Map[String, AttributeKey[?]],
-    val taskToKey: Map[Task[?], ScopedKey[Task[?]]],
     val triggers: Triggers,
     val keyIndex: KeyIndex,
     val aggregateKeyIndex: KeyIndex,
@@ -271,7 +270,7 @@ final class LoadedBuild(val root: URI, val units: Map[URI, LoadedBuildUnit]) {
       unit.projects.map(p => ProjectRef(build, p.id) -> p)
     }.toIndexedSeq
 
-  def extra(data: Settings[Scope])(keyIndex: KeyIndex): BuildUtil[ResolvedProject] =
+  def extra(data: Def.Settings)(keyIndex: KeyIndex): BuildUtil[ResolvedProject] =
     BuildUtil(root, units, keyIndex, data)
 
   private[sbt] def autos = GroupedAutoPlugins(units)
@@ -309,7 +308,7 @@ object BuildStreams {
   def mkStreams(
       units: Map[URI, LoadedBuildUnit],
       root: URI,
-      data: Settings[Scope]
+      data: Def.Settings
   ): State => Streams = s => {
     s.get(Keys.stateStreams).getOrElse {
       std.Streams(
@@ -324,7 +323,7 @@ object BuildStreams {
     }
   }
 
-  def path(units: Map[URI, LoadedBuildUnit], root: URI, data: Settings[Scope])(
+  def path(units: Map[URI, LoadedBuildUnit], root: URI, data: Def.Settings)(
       scoped: ScopedKey[?]
   ): File =
     resolvePath(projectPath(units, root, scoped, data), nonProjectPath(scoped))
@@ -386,7 +385,7 @@ object BuildStreams {
       units: Map[URI, LoadedBuildUnit],
       root: URI,
       scoped: ScopedKey[?],
-      data: Settings[Scope]
+      data: Def.Settings
   ): File =
     scoped.scope.project match {
       case Zero => refTarget(GlobalScope, units(root).localBase, data) / GlobalPath
@@ -397,9 +396,9 @@ object BuildStreams {
       case This => sys.error("Unresolved project reference (This) in " + displayFull(scoped))
     }
 
-  def refTarget(ref: ResolvedReference, fallbackBase: File, data: Settings[Scope]): File =
+  def refTarget(ref: ResolvedReference, fallbackBase: File, data: Def.Settings): File =
     refTarget(GlobalScope.copy(project = Select(ref)), fallbackBase, data)
 
-  def refTarget(scope: Scope, fallbackBase: File, data: Settings[Scope]): File =
+  def refTarget(scope: Scope, fallbackBase: File, data: Def.Settings): File =
     ((scope / Keys.target).get(data) getOrElse outputDirectory(fallbackBase)) / StreamsDirectory
 }
diff --git a/main/src/main/scala/sbt/internal/BuildUtil.scala b/main/src/main/scala/sbt/internal/BuildUtil.scala
index 1cbab6e24..5b6cce1f0 100644
--- a/main/src/main/scala/sbt/internal/BuildUtil.scala
+++ b/main/src/main/scala/sbt/internal/BuildUtil.scala
@@ -9,13 +9,13 @@
 package sbt
 package internal
 
-import sbt.internal.util.{ Relation, Settings, Dag }
+import sbt.internal.util.{ Relation, Dag }
 
 import java.net.URI
 
 final class BuildUtil[Proj](
     val keyIndex: KeyIndex,
-    val data: Settings[Scope],
+    val data: Def.Settings,
     val root: URI,
     val rootProjectID: URI => String,
     val project: (URI, String) => Proj,
@@ -57,7 +57,7 @@ object BuildUtil {
       root: URI,
       units: Map[URI, LoadedBuildUnit],
       keyIndex: KeyIndex,
-      data: Settings[Scope]
+      data: Def.Settings
   ): BuildUtil[ResolvedProject] = {
     val getp = (build: URI, project: String) => Load.getProject(units, build, project)
     val configs = (_: ResolvedProject).configurations.map(c => ConfigKey(c.name))
diff --git a/main/src/main/scala/sbt/internal/ClasspathImpl.scala b/main/src/main/scala/sbt/internal/ClasspathImpl.scala
index a18d1c0fc..2f8c5af69 100644
--- a/main/src/main/scala/sbt/internal/ClasspathImpl.scala
+++ b/main/src/main/scala/sbt/internal/ClasspathImpl.scala
@@ -15,7 +15,7 @@ import sbt.Keys._
 import sbt.nio.Keys._
 import sbt.nio.file.{ Glob, RecursiveGlob }
 import sbt.Def.Initialize
-import sbt.internal.util.{ Attributed, Dag, Settings }
+import sbt.internal.util.{ Attributed, Dag }
 import sbt.librarymanagement.{ Configuration, TrackLevel }
 import sbt.librarymanagement.Configurations.names
 import sbt.std.TaskExtra._
@@ -180,7 +180,7 @@ private[sbt] object ClasspathImpl {
       projectRef: ProjectRef,
       conf: Configuration,
       self: Configuration,
-      data: Settings[Scope],
+      data: Def.Settings,
       deps: BuildDependencies,
       track: TrackLevel,
       log: Logger
@@ -198,7 +198,7 @@ private[sbt] object ClasspathImpl {
         projectRef: ProjectRef,
         conf: Configuration,
         self: Configuration,
-        data: Settings[Scope],
+        data: Def.Settings,
         deps: BuildDependencies,
         track: TrackLevel,
         log: Logger
@@ -244,7 +244,7 @@ private[sbt] object ClasspathImpl {
       projectRef: ProjectRef,
       conf: Configuration,
       self: Configuration,
-      data: Settings[Scope],
+      data: Def.Settings,
       deps: BuildDependencies,
       track: TrackLevel,
       log: Logger
@@ -282,7 +282,7 @@ private[sbt] object ClasspathImpl {
   def unmanagedDependencies0(
       projectRef: ProjectRef,
       conf: Configuration,
-      data: Settings[Scope],
+      data: Def.Settings,
       deps: BuildDependencies,
       log: Logger
   ): Initialize[Task[Classpath]] =
@@ -306,7 +306,7 @@ private[sbt] object ClasspathImpl {
   def unmanagedLibs(
       dep: ResolvedReference,
       conf: String,
-      data: Settings[Scope]
+      data: Def.Settings
   ): Task[Classpath] =
     getClasspath(unmanagedJars, dep, conf, data)
 
@@ -315,7 +315,7 @@ private[sbt] object ClasspathImpl {
       deps: BuildDependencies,
       conf: Configuration,
       self: Configuration,
-      data: Settings[Scope],
+      data: Def.Settings,
       track: TrackLevel,
       includeSelf: Boolean,
       log: Logger
@@ -346,7 +346,7 @@ private[sbt] object ClasspathImpl {
   def interSort(
       projectRef: ProjectRef,
       conf: Configuration,
-      data: Settings[Scope],
+      data: Def.Settings,
       deps: BuildDependencies
   ): Seq[(ProjectRef, String)] =
     val visited = (new LinkedHashSet[(ProjectRef, String)]).asScala
@@ -431,7 +431,7 @@ private[sbt] object ClasspathImpl {
   def allConfigs(conf: Configuration): Seq[Configuration] =
     Dag.topologicalSort(conf)(_.extendsConfigs)
 
-  def getConfigurations(p: ResolvedReference, data: Settings[Scope]): Seq[Configuration] =
+  def getConfigurations(p: ResolvedReference, data: Def.Settings): Seq[Configuration] =
     (p / ivyConfigurations).get(data).getOrElse(Nil)
 
   def confOpt(configurations: Seq[Configuration], conf: String): Option[Configuration] =
@@ -441,14 +441,14 @@ private[sbt] object ClasspathImpl {
       key: TaskKey[Seq[A]],
       dep: ResolvedReference,
       conf: Configuration,
-      data: Settings[Scope]
+      data: Def.Settings
   ): Task[Seq[A]] = getClasspath(key, dep, conf.name, data)
 
   def getClasspath[A](
       key: TaskKey[Seq[A]],
       dep: ResolvedReference,
       conf: String,
-      data: Settings[Scope]
+      data: Def.Settings
   ): Task[Seq[A]] =
     (dep / ConfigKey(conf) / key).get(data) match {
       case Some(x) => x
diff --git a/main/src/main/scala/sbt/internal/Clean.scala b/main/src/main/scala/sbt/internal/Clean.scala
index 48a0b5d48..14075307d 100644
--- a/main/src/main/scala/sbt/internal/Clean.scala
+++ b/main/src/main/scala/sbt/internal/Clean.scala
@@ -114,11 +114,9 @@ private[sbt] object Clean {
           // This is the special portion of the task where we clear out the relevant streams
           // and file outputs of a task.
           val streamsKey = scope.task.toOption.map(k => ScopedKey(scope.copy(task = Zero), k))
+          val stampKey = ScopedKey(scope, inputFileStamps.key)
           val stampsKey =
-            extracted.structure.data.getDirect(scope, inputFileStamps.key) match {
-              case Some(_) => ScopedKey(scope, inputFileStamps.key) :: Nil
-              case _       => Nil
-            }
+            if extracted.structure.data.contains(stampKey) then stampKey :: Nil else Nil
           val streamsGlobs =
             (streamsKey.toSeq ++ stampsKey)
               .map(k => manager(k).cacheDirectory.toPath.toGlob / **)
diff --git a/main/src/main/scala/sbt/internal/GlobalPlugin.scala b/main/src/main/scala/sbt/internal/GlobalPlugin.scala
index 3635b4c55..0fe096a8e 100644
--- a/main/src/main/scala/sbt/internal/GlobalPlugin.scala
+++ b/main/src/main/scala/sbt/internal/GlobalPlugin.scala
@@ -92,7 +92,7 @@ object GlobalPlugin {
         (prods ++ intcp).distinct
       )(updateReport.value)
     }
-    val resolvedTaskInit = taskInit.mapReferenced(Project.mapScope(Scope.replaceThis(p)))
+    val resolvedTaskInit = taskInit.mapReferenced(Project.replaceThis(p))
     val task = resolvedTaskInit.evaluate(data)
     val roots = resolvedTaskInit.dependencies
     evaluate(state, structure, task, roots)
diff --git a/main/src/main/scala/sbt/internal/Inspect.scala b/main/src/main/scala/sbt/internal/Inspect.scala
index 76b1a5072..127eb551c 100644
--- a/main/src/main/scala/sbt/internal/Inspect.scala
+++ b/main/src/main/scala/sbt/internal/Inspect.scala
@@ -87,8 +87,7 @@ object Inspect {
     val extracted = Project.extract(s)
     import extracted._
     option match {
-      case Details(actual) =>
-        Project.details(extracted.structure, actual, sk.scope, sk.key)
+      case Details(actual) => Project.details(extracted.structure, actual, sk)
       case DependencyTreeMode =>
         val basedir = new File(Project.session(s).current.build)
         Project
diff --git a/main/src/main/scala/sbt/internal/KeyIndex.scala b/main/src/main/scala/sbt/internal/KeyIndex.scala
index 4c6be3ef4..9b3545413 100644
--- a/main/src/main/scala/sbt/internal/KeyIndex.scala
+++ b/main/src/main/scala/sbt/internal/KeyIndex.scala
@@ -29,30 +29,14 @@ object KeyIndex {
   }
 
   def aggregate(
-      known: Iterable[ScopedKey[?]],
+      known: Set[ScopedKey[?]],
       extra: BuildUtil[?],
       projects: Map[URI, Set[String]],
       configurations: Map[String, Seq[Configuration]]
-  ): ExtendableKeyIndex = {
-    /*
-     * Used to be:
-     * (base(projects, configurations) /: known) { (index, key) =>
-     *   index.addAggregated(key, extra)
-     * }
-     * This was a significant serial bottleneck during project loading that we can work around by
-     * computing the aggregations in parallel and then bulk adding them to the index.
-     */
-    import scala.collection.parallel.CollectionConverters.*
-    val toAggregate = known.par.map {
-      case key if validID(key.key.label) =>
-        Aggregation.aggregate(key, ScopeMask(), extra, reverse = true)
-      case _ => Nil
-    }
-    toAggregate.foldLeft(base(projects, configurations)) {
-      case (index, Nil)  => index
-      case (index, keys) => keys.foldLeft(index)(_.add(_))
-    }
-  }
+  ): ExtendableKeyIndex =
+    Aggregation
+      .reverseAggregate(known.filter(k => validID(k.key.label)), extra)
+      .foldLeft(base(projects, configurations))(_.add(_))
 
   private def base(
       projects: Map[URI, Set[String]],
@@ -278,7 +262,7 @@ private[sbt] final class KeyIndex0(val data: BuildIndex) extends ExtendableKeyIn
 
   def addAggregated(scoped: ScopedKey[?], extra: BuildUtil[?]): ExtendableKeyIndex =
     if (validID(scoped.key.label)) {
-      val aggregateProjects = Aggregation.aggregate(scoped, ScopeMask(), extra, reverse = true)
+      val aggregateProjects = Aggregation.reverseAggregate(Set(scoped), extra)
       aggregateProjects.foldLeft(this: ExtendableKeyIndex)(_.add(_))
     } else this
 
diff --git a/main/src/main/scala/sbt/internal/LintUnused.scala b/main/src/main/scala/sbt/internal/LintUnused.scala
index ed7336a93..4ad806e4a 100644
--- a/main/src/main/scala/sbt/internal/LintUnused.scala
+++ b/main/src/main/scala/sbt/internal/LintUnused.scala
@@ -94,7 +94,7 @@ object LintUnused {
   }
 
   def lintResultLines(
-      result: Seq[(ScopedKey[?], String, Vector[SourcePosition])]
+      result: Seq[(ScopedKey[?], String, Seq[SourcePosition])]
   ): Vector[String] = {
     import scala.collection.mutable.ListBuffer
     val buffer = ListBuffer.empty[String]
@@ -127,7 +127,7 @@ object LintUnused {
       state: State,
       includeKeys: String => Boolean,
       excludeKeys: String => Boolean
-  ): Seq[(ScopedKey[?], String, Vector[SourcePosition])] = {
+  ): Seq[(ScopedKey[?], String, Seq[SourcePosition])] = {
     val extracted = Project.extract(state)
     val structure = extracted.structure
     val display = Def.showShortKey(None) // extracted.showKey
@@ -135,17 +135,11 @@ object LintUnused {
     val cMap = Def.flattenLocals(comp)
     val used: Set[ScopedKey[?]] = cMap.values.flatMap(_.dependencies).toSet
     val unused: Seq[ScopedKey[?]] = cMap.keys.filter(!used.contains(_)).toSeq
-    val withDefinedAts: Seq[UnusedKey] = unused map { u =>
-      val definingScope = structure.data.definingScope(u.scope, u.key)
-      val definingScoped = definingScope match {
-        case Some(sc) => ScopedKey(sc, u.key)
-        case _        => u
-      }
-      val definedAt = comp.get(definingScoped) match {
-        case Some(c) => definedAtString(c.settings.toVector)
+    val withDefinedAts: Seq[UnusedKey] = unused.map { u =>
+      val data = Project.scopedKeyData(structure, u)
+      val definedAt = comp.get(data.map(_.definingKey).getOrElse(u)) match
+        case Some(c) => definedAtString(c.settings)
         case _       => Vector.empty
-      }
-      val data = Project.scopedKeyData(structure, u.scope, u.key)
       UnusedKey(u, definedAt, data)
     }
 
@@ -167,18 +161,16 @@ object LintUnused {
             && isLocallyDefined(u) =>
         u
     }
-    (unusedKeys map { u =>
-      (u.scoped, display.show(u.scoped), u.positions)
-    }).sortBy(_._2)
+    unusedKeys.map(u => (u.scoped, display.show(u.scoped), u.positions)).sortBy(_._2)
   }
 
   private case class UnusedKey(
       scoped: ScopedKey[?],
-      positions: Vector[SourcePosition],
+      positions: Seq[SourcePosition],
       data: Option[ScopedKeyData[?]]
   )
 
-  private def definedAtString(settings: Vector[Setting[?]]): Vector[SourcePosition] = {
+  private def definedAtString(settings: Seq[Setting[?]]): Seq[SourcePosition] = {
     settings flatMap { setting =>
       setting.pos match {
         case NoPosition => Vector.empty
diff --git a/main/src/main/scala/sbt/internal/Load.scala b/main/src/main/scala/sbt/internal/Load.scala
index 7878dd305..513edff01 100755
--- a/main/src/main/scala/sbt/internal/Load.scala
+++ b/main/src/main/scala/sbt/internal/Load.scala
@@ -21,7 +21,7 @@ import sbt.internal.inc.classpath.ClasspathUtil
 import sbt.internal.inc.{ MappedFileConverter, ScalaInstance, ZincLmUtil, ZincUtil }
 import sbt.internal.util.Attributed.data
 import sbt.internal.util.Types.const
-import sbt.internal.util.{ Attributed, Settings }
+import sbt.internal.util.Attributed
 import sbt.internal.server.BuildServerEvalReporter
 import sbt.io.{ GlobFilter, IO }
 import sbt.librarymanagement.ivy.{ InlineIvyConfiguration, IvyDependencyResolution, IvyPaths }
@@ -310,7 +310,7 @@ private[sbt] object Load {
     (rootEval, bs)
   }
 
-  private def checkTargets(data: Settings[Scope]): Option[String] =
+  private def checkTargets(data: Def.Settings): Option[String] =
     val dups = overlappingTargets(allTargets(data))
     if (dups.isEmpty) None
     else {
@@ -323,7 +323,7 @@ private[sbt] object Load {
   private def overlappingTargets(targets: Seq[(ProjectRef, File)]): Map[File, Seq[ProjectRef]] =
     targets.groupBy(_._2).view.filter(_._2.size > 1).mapValues(_.map(_._1)).toMap
 
-  private def allTargets(data: Settings[Scope]): Seq[(ProjectRef, File)] = {
+  private def allTargets(data: Def.Settings): Seq[(ProjectRef, File)] = {
     import ScopeFilter._
     val allProjects = ScopeFilter(Make.inAnyProject)
     val targetAndRef = Def.setting { (Keys.thisProjectRef.value, Keys.target.value) }
@@ -366,25 +366,24 @@ private[sbt] object Load {
   }
 
   def setDefinitionKey[T](tk: Task[T], key: ScopedKey[?]): Task[T] =
-    if (isDummy(tk)) tk else Task(tk.info.set(Keys.taskDefinitionKey, key), tk.work)
+    if (isDummy(tk)) tk else tk.set(Keys.taskDefinitionKey, key)
 
   def structureIndex(
-      data: Settings[Scope],
+      data: Def.Settings,
       settings: Seq[Setting[?]],
       extra: KeyIndex => BuildUtil[?],
       projects: Map[URI, LoadedBuildUnit]
   ): StructureIndex = {
     val keys = Index.allKeys(settings)
-    val attributeKeys = Index.attributeKeys(data) ++ keys.map(_.key)
-    val scopedKeys = keys ++ data.allKeys((s, k) => ScopedKey(s, k)).toVector
+    val attributeKeys = data.attributeKeys ++ keys.map(_.key)
+    val scopedKeys = keys ++ data.keys
     val projectsMap = projects.view.mapValues(_.defined.keySet).toMap
     val configsMap: Map[String, Seq[Configuration]] =
       projects.values.flatMap(bu => bu.defined map { case (k, v) => (k, v.configurations) }).toMap
-    val keyIndex = KeyIndex(scopedKeys.toVector, projectsMap, configsMap)
-    val aggIndex = KeyIndex.aggregate(scopedKeys.toVector, extra(keyIndex), projectsMap, configsMap)
+    val keyIndex = KeyIndex(scopedKeys, projectsMap, configsMap)
+    val aggIndex = KeyIndex.aggregate(scopedKeys, extra(keyIndex), projectsMap, configsMap)
     new StructureIndex(
       Index.stringToKeyMap(attributeKeys),
-      Index.taskToKeyMap(data),
       Index.triggers(data),
       keyIndex,
       aggIndex
diff --git a/main/src/main/scala/sbt/internal/LogManager.scala b/main/src/main/scala/sbt/internal/LogManager.scala
index d5268f61b..cc786db7c 100644
--- a/main/src/main/scala/sbt/internal/LogManager.scala
+++ b/main/src/main/scala/sbt/internal/LogManager.scala
@@ -22,7 +22,7 @@ import java.io.PrintWriter
 
 sealed abstract class LogManager {
   def apply(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State,
       task: ScopedKey[?],
       writer: PrintWriter,
@@ -30,20 +30,20 @@ sealed abstract class LogManager {
   ): ManagedLogger
   @deprecated("Use alternate apply that provides a LoggerContext", "1.4.0")
   def apply(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State,
       task: ScopedKey[?],
       writer: PrintWriter
   ): ManagedLogger = apply(data, state, task, writer, LoggerContext.globalContext)
 
   def backgroundLog(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State,
       task: ScopedKey[?],
       context: LoggerContext
   ): ManagedLogger
   @deprecated("Use alternate background log that provides a LoggerContext", "1.4.0")
-  final def backgroundLog(data: Settings[Scope], state: State, task: ScopedKey[?]): ManagedLogger =
+  final def backgroundLog(data: Def.Settings, state: State, task: ScopedKey[?]): ManagedLogger =
     backgroundLog(data, state, task, LoggerContext.globalContext)
 }
 
@@ -62,7 +62,7 @@ object LogManager {
   // This is called by mkStreams
   //
   def construct(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State
   ): (ScopedKey[?], PrintWriter) => ManagedLogger =
     (task: ScopedKey[?], to: PrintWriter) => {
@@ -74,7 +74,7 @@ object LogManager {
 
   @deprecated("Use alternate constructBackgroundLog that provides a LoggerContext", "1.8.0")
   def constructBackgroundLog(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State
   ): ScopedKey[?] => ManagedLogger = {
     val context = state.get(Keys.loggerContext).getOrElse(LoggerContext.globalContext)
@@ -82,7 +82,7 @@ object LogManager {
   }
 
   def constructBackgroundLog(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State,
       context: LoggerContext
   ): (ScopedKey[?]) => ManagedLogger =
@@ -119,7 +119,7 @@ object LogManager {
       extra: AppenderSupplier
   ) extends LogManager {
     def apply(
-        data: Settings[Scope],
+        data: Def.Settings,
         state: State,
         task: ScopedKey[?],
         to: PrintWriter,
@@ -137,7 +137,7 @@ object LogManager {
       )
 
     def backgroundLog(
-        data: Settings[Scope],
+        data: Def.Settings,
         state: State,
         task: ScopedKey[?],
         context: LoggerContext
@@ -150,16 +150,16 @@ object LogManager {
   // to change from global being the default to overriding, switch the order of state.get and data.get
   def getOr[T](
       key: AttributeKey[T],
-      data: Settings[Scope],
+      data: Def.Settings,
       scope: Scope,
       state: State,
       default: T
   ): T =
-    data.get(scope, key) orElse state.get(key) getOrElse default
+    data.get(ScopedKey(scope, key)).orElse(state.get(key)).getOrElse(default)
 
   @deprecated("Use defaultLogger that provides a LoggerContext", "1.4.0")
   def defaultLogger(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State,
       task: ScopedKey[?],
       console: Appender,
@@ -170,7 +170,7 @@ object LogManager {
     defaultLogger(data, state, task, console, backed, relay, extra, LoggerContext.globalContext)
   // This is the main function that is used to generate the logger for tasks.
   def defaultLogger(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State,
       task: ScopedKey[?],
       console: Appender,
@@ -242,7 +242,7 @@ object LogManager {
   }
 
   def backgroundLog(
-      data: Settings[Scope],
+      data: Def.Settings,
       state: State,
       task: ScopedKey[?],
       console: Appender,
@@ -271,7 +271,7 @@ object LogManager {
 
   // TODO: Fix this
   // if global logging levels are not explicitly set, set them from project settings
-  // private[sbt] def setGlobalLogLevels(s: State, data: Settings[Scope]): State =
+  // private[sbt] def setGlobalLogLevels(s: State, data: Def.Settings): State =
   //   if (hasExplicitGlobalLogLevels(s))
   //     s
   //   else {
diff --git a/main/src/main/scala/sbt/internal/ProjectQuery.scala b/main/src/main/scala/sbt/internal/ProjectQuery.scala
index 33743eabf..b79e86b5b 100644
--- a/main/src/main/scala/sbt/internal/ProjectQuery.scala
+++ b/main/src/main/scala/sbt/internal/ProjectQuery.scala
@@ -24,7 +24,8 @@ private[sbt] case class ProjectQuery(
       val scalaMatches =
         params.get(Keys.scalaBinaryVersion.key) match
           case Some(expected) =>
-            val actualSbv = structure.data.get(Scope.ThisScope.rescope(p), scalaBinaryVersion.key)
+            val actualSbv =
+              structure.data.get(Def.ScopedKey(Scope.ThisScope.rescope(p), scalaBinaryVersion.key))
             actualSbv match
               case Some(sbv) => sbv == expected
               case None      => true
diff --git a/main/src/main/scala/sbt/internal/SettingCompletions.scala b/main/src/main/scala/sbt/internal/SettingCompletions.scala
index 615ed67e8..a16513ced 100644
--- a/main/src/main/scala/sbt/internal/SettingCompletions.scala
+++ b/main/src/main/scala/sbt/internal/SettingCompletions.scala
@@ -9,7 +9,7 @@
 package sbt
 package internal
 
-import sbt.internal.util.{ AttributeKey, complete, Relation, Settings, Util }
+import sbt.internal.util.{ AttributeKey, complete, Relation, Util }
 import sbt.util.Show
 import sbt.librarymanagement.Configuration
 
@@ -138,7 +138,7 @@ private[sbt] object SettingCompletions {
    * The last part of the completion will generate a template for the value or function literal that will initialize the setting or task.
    */
   def settingParser(
-      settings: Settings[Scope],
+      settings: Def.Settings,
       rawKeyMap: Map[String, AttributeKey[?]],
       context: ResolvedProject,
   ): Parser[String] = {
@@ -156,7 +156,7 @@ private[sbt] object SettingCompletions {
   /** Parser for a Scope+AttributeKey (ScopedKey). */
   def scopedKeyParser(
       keyMap: Map[String, AttributeKey[?]],
-      settings: Settings[Scope],
+      settings: Def.Settings,
       context: ResolvedProject
   ): Parser[ScopedKey[?]] = {
     val cutoff = KeyRanks.MainCutoff
@@ -195,15 +195,11 @@ private[sbt] object SettingCompletions {
    */
   def scopeParser(
       key: AttributeKey[?],
-      settings: Settings[Scope],
+      settings: Def.Settings,
       context: ResolvedProject
   ): Parser[Scope] = {
-    val data = settings.data
-    val allScopes = data.keys.toSeq
-    val definedScopes = data.toSeq flatMap { case (scope, attrs) =>
-      if attrs.contains(key) then scope :: Nil else Nil
-    }
-    scope(allScopes, definedScopes, context)
+    val definedScopes = settings.keys.collect { case sk if sk.key == key => sk.scope }
+    scope(settings.scopes.toSeq, definedScopes.toSeq, context)
   }
 
   private def scope(
diff --git a/main/src/main/scala/sbt/internal/SettingGraph.scala b/main/src/main/scala/sbt/internal/SettingGraph.scala
index 5d66531f8..1d725a12c 100644
--- a/main/src/main/scala/sbt/internal/SettingGraph.scala
+++ b/main/src/main/scala/sbt/internal/SettingGraph.scala
@@ -25,11 +25,8 @@ object SettingGraph {
       compiled(structure.settings, false)(using structure.delegates, structure.scopeLocal, display)
     )
     def loop(scoped: ScopedKey[?], generation: Int): SettingGraph = {
-      val key = scoped.key
-      val scope = scoped.scope
-      val definedIn = structure.data.definingScope(scope, key) map { sc =>
-        display.show(ScopedKey(sc, key))
-      }
+      val data = Project.scopedKeyData(structure, scoped)
+      val definedIn = data.map(d => display.show(d.definingKey))
       val depends = cMap.get(scoped) match {
         case Some(c) => c.dependencies.toSet; case None => Set.empty
       }
@@ -39,8 +36,8 @@ object SettingGraph {
       SettingGraph(
         display.show(scoped),
         definedIn,
-        Project.scopedKeyData(structure, scope, key),
-        key.description,
+        data,
+        scoped.key.description,
         basedir,
         depends map { (x: ScopedKey[?]) =>
           loop(x, generation + 1)
diff --git a/main/src/main/scala/sbt/internal/TaskName.scala b/main/src/main/scala/sbt/internal/TaskName.scala
index 45199bc66..840c0bcca 100644
--- a/main/src/main/scala/sbt/internal/TaskName.scala
+++ b/main/src/main/scala/sbt/internal/TaskName.scala
@@ -15,9 +15,9 @@ import Keys.taskDefinitionKey
 private[sbt] object TaskName {
   def name(node: Task[?]): String = definedName(node).getOrElse(anonymousName(node))
   def definedName(node: Task[?]): Option[String] =
-    node.info.name.orElse(transformNode(node).map(displayFull))
+    node.name.orElse(transformNode(node).map(displayFull))
   def anonymousName(node: TaskId[?]): String =
     "<anon-" + System.identityHashCode(node).toHexString + ">"
   def transformNode(node: Task[?]): Option[ScopedKey[?]] =
-    node.info.attributes.get(taskDefinitionKey)
+    node.get(taskDefinitionKey)
 }
diff --git a/main/src/main/scala/sbt/internal/WatchTransitiveDependencies.scala b/main/src/main/scala/sbt/internal/WatchTransitiveDependencies.scala
index d0c29b518..927e85e77 100644
--- a/main/src/main/scala/sbt/internal/WatchTransitiveDependencies.scala
+++ b/main/src/main/scala/sbt/internal/WatchTransitiveDependencies.scala
@@ -16,7 +16,6 @@ import sbt.ProjectExtra.*
 import sbt.SlashSyntax0.given
 import sbt.internal.io.Source
 import sbt.internal.nio.Globs
-import sbt.internal.util.AttributeMap
 import sbt.internal.util.complete.Parser
 import sbt.nio.FileStamper
 import sbt.nio.Keys._
@@ -54,7 +53,7 @@ private[sbt] object WatchTransitiveDependencies {
       val state: State
   ) {
     def structure: BuildStructure = extracted.structure
-    def data: Map[Scope, AttributeMap] = extracted.structure.data.data
+    def data: Settings = extracted.structure.data
   }
 
   private def argumentsImpl(
@@ -113,18 +112,18 @@ private[sbt] object WatchTransitiveDependencies {
     val keys = collectKeys(args, allKeys, Set.empty, Set.empty)
     def getDynamicInputs(scopedKey: ScopedKey[Seq[Glob]], trigger: Boolean): Seq[DynamicInput] = {
       data
-        .get(scopedKey.scope)
-        .map { am =>
-          am.get(scopedKey.key) match {
-            case Some(globs: Seq[Glob]) =>
-              if (!trigger) {
-                val stamper = am.get(inputFileStamper.key).getOrElse(FileStamper.Hash)
-                val forceTrigger = am.get(watchForceTriggerOnAnyChange.key).getOrElse(false)
-                globs.map(g => DynamicInput(g, stamper, forceTrigger))
-              } else {
-                globs.map(g => DynamicInput(g, FileStamper.LastModified, forceTrigger = true))
-              }
-            case None => Nil: Seq[DynamicInput]
+        .getDirect(scopedKey)
+        .map { globs =>
+          if (!trigger) {
+            val stamper =
+              data.getDirect(scopedKey.copy(key = inputFileStamper.key)).getOrElse(FileStamper.Hash)
+            val forceTrigger =
+              data
+                .getDirect(scopedKey.copy(key = watchForceTriggerOnAnyChange.key))
+                .getOrElse(false)
+            globs.map(g => DynamicInput(g, stamper, forceTrigger))
+          } else {
+            globs.map(g => DynamicInput(g, FileStamper.LastModified, forceTrigger = true))
           }
         }
         .getOrElse(Nil)
@@ -148,21 +147,15 @@ private[sbt] object WatchTransitiveDependencies {
         .toIndexedSeq
     val projects = projectScopes.flatMap(_.project.toOption).distinct.toSet
     val scopes: Seq[Either[Scope, Seq[Glob]]] =
-      data.flatMap { case (s, am) =>
-        if (s == Scope.Global || s.project.toOption.exists(projects.contains))
-          am.get(Keys.watchSources.key) match {
-            case Some(k) =>
-              k.work match {
-                // Avoid extracted.runTask if possible.
-                case Action.Pure(w, _) => Some(Right(w().map(_.toGlob)))
-                case _                 => Some(Left(s))
-              }
-            case _ => None
+      data.scopes.toSeq
+        .filter(s => s == Scope.Global || s.project.toOption.exists(projects.contains))
+        .flatMap { s =>
+          data.getDirect(ScopedKey(s, Keys.watchSources.key)).map { task =>
+            task.work match
+              case a: Action.Pure[Seq[Watched.WatchSource]] => Right(a.f().map(_.toGlob))
+              case _                                        => Left(s)
           }
-        else {
-          None
         }
-      }.toSeq
     def toDynamicInput(glob: Glob): DynamicInput =
       DynamicInput(glob, FileStamper.LastModified, forceTrigger = true)
     scopes.flatMap {
diff --git a/main/src/main/scala/sbt/internal/server/SettingQuery.scala b/main/src/main/scala/sbt/internal/server/SettingQuery.scala
index 86a824c3f..3b7b563bc 100644
--- a/main/src/main/scala/sbt/internal/server/SettingQuery.scala
+++ b/main/src/main/scala/sbt/internal/server/SettingQuery.scala
@@ -19,7 +19,7 @@ import sjsonnew._
 import sjsonnew.support.scalajson.unsafe._
 
 object SettingQuery {
-  import sbt.internal.util.{ AttributeKey, Settings }
+  import sbt.internal.util.AttributeKey
   import sbt.internal.util.complete.{ DefaultParsers, Parser }, DefaultParsers._
   import sbt.Def.{ showBuildRelativeKey2, ScopedKey }
 
@@ -70,7 +70,7 @@ object SettingQuery {
       currentBuild: URI,
       defaultConfigs: Option[ResolvedReference] => Seq[String],
       keyMap: Map[String, AttributeKey[?]],
-      data: Settings[Scope]
+      data: Def.Settings
   ): Parser[ParsedKey] =
     scopedKeyFull(index, currentBuild, defaultConfigs, keyMap) flatMap { choices =>
       Act.select(choices, data)(showBuildRelativeKey2(currentBuild))
@@ -81,7 +81,7 @@ object SettingQuery {
       currentBuild: URI,
       defaultConfigs: Option[ResolvedReference] => Seq[String],
       keyMap: Map[String, AttributeKey[?]],
-      data: Settings[Scope]
+      data: Def.Settings
   ): Parser[ScopedKey[?]] =
     scopedKeySelected(index, currentBuild, defaultConfigs, keyMap, data).map(_.key)
 
@@ -96,7 +96,7 @@ object SettingQuery {
 
   def getSettingValue[A](structure: BuildStructure, key: Def.ScopedKey[A]): Either[String, A] =
     structure.data
-      .get(key.scope, key.key)
+      .get(key)
       .toRight(s"Key ${Def.displayFull(key)} not found")
       .flatMap {
         case _: Task[_] => Left(s"Key ${Def.displayFull(key)} is a task, can only query settings")
diff --git a/main/src/main/scala/sbt/nio/Settings.scala b/main/src/main/scala/sbt/nio/Settings.scala
index e7f7462a0..eff12b903 100644
--- a/main/src/main/scala/sbt/nio/Settings.scala
+++ b/main/src/main/scala/sbt/nio/Settings.scala
@@ -145,7 +145,7 @@ private[sbt] object Settings {
    * @return the setting with the task definition
    */
   private def addTaskDefinition[T](setting: Def.Setting[Task[T]]): Def.Setting[Task[T]] =
-    setting.mapInit((sk, task) => Task(task.info.set(taskDefinitionKey, sk), task.work))
+    setting.mapInit((sk, task) => task.set(taskDefinitionKey, sk))
 
   /**
    * Returns all of the paths described by a glob along with their basic file attributes.
diff --git a/main/src/test/scala/PluginCommandTest.scala b/main/src/test/scala/PluginCommandTest.scala
index 55268b6d0..eeb81a9d9 100644
--- a/main/src/test/scala/PluginCommandTest.scala
+++ b/main/src/test/scala/PluginCommandTest.scala
@@ -17,7 +17,6 @@ import sbt.internal.util.{
   ConsoleOut,
   GlobalLogging,
   MainAppender,
-  Settings,
   Terminal,
 }
 import sbt.internal.inc.PlainVirtualFileConverter
@@ -97,7 +96,7 @@ object FakeState {
     val delegates: (Scope) => Seq[Scope] = _ => Nil
     val scopeLocal: Def.ScopeLocal = _ => Nil
 
-    val (cMap, data: Settings[Scope]) =
+    val (cMap, data: Def.Settings) =
       Def.makeWithCompiledMap(settings)(using delegates, scopeLocal, Def.showFullKey)
     val extra: KeyIndex => BuildUtil[?] = (keyIndex) =>
       BuildUtil(base.toURI, Map.empty, keyIndex, data)
diff --git a/main/src/test/scala/sbt/internal/TestBuild.scala b/main/src/test/scala/sbt/internal/TestBuild.scala
index ee68dc371..48dbec92e 100644
--- a/main/src/test/scala/sbt/internal/TestBuild.scala
+++ b/main/src/test/scala/sbt/internal/TestBuild.scala
@@ -10,7 +10,7 @@ package sbt
 package internal
 
 import Def.{ ScopedKey, Setting }
-import sbt.internal.util.{ AttributeKey, AttributeMap, Relation, Settings }
+import sbt.internal.util.{ AttributeKey, Relation }
 import sbt.internal.util.Types.{ const, some }
 import sbt.internal.util.complete.Parser
 import sbt.librarymanagement.Configuration
@@ -59,17 +59,18 @@ abstract class TestBuild {
   sealed case class Structure(
       env: Env,
       current: ProjectRef,
-      data: Settings[Scope],
+      data: Def.Settings,
       keyIndex: KeyIndex,
       keyMap: Map[String, AttributeKey[?]]
   ) {
     override def toString =
       env.toString + "\n" + "current: " + current + "\nSettings:\n\t" + showData + keyMap.keys
         .mkString("All keys:\n\t", ", ", "")
-    def showKeys(map: AttributeMap): String = map.keys.mkString("\n\t   ", ",", "\n")
+    def showKeys(keys: Iterable[AttributeKey[?]]): String = keys.mkString("\n\t   ", ",", "\n")
     def showData: String = {
       val scopeStrings =
-        for ((scope, map) <- data.data) yield (Scope.display(scope, "<key>"), showKeys(map))
+        for (scope, keys) <- data.keys.groupMap(_.scope)(_.key)
+        yield (Scope.display(scope, "<key>"), showKeys(keys))
       scopeStrings.toSeq.sorted.map(t => t._1 + t._2).mkString("\n\t")
     }
     val extra: BuildUtil[Proj] = {
@@ -86,11 +87,10 @@ abstract class TestBuild {
     }
 
     lazy val allAttributeKeys: Set[AttributeKey[?]] = {
-      val x = data.data.values.flatMap(_.keys).toSet
-      if (x.isEmpty) {
+      if (data.attributeKeys.isEmpty) {
         sys.error("allAttributeKeys is empty")
       }
-      x
+      data.attributeKeys
     }
     lazy val (taskAxes, zeroTaskAxis, onlyTaskAxis, multiTaskAxis) = {
       import collection.mutable
@@ -98,11 +98,10 @@ abstract class TestBuild {
 
       // task axis of Scope is set to Zero and the value of the second map is the original task axis
       val taskAxesMappings =
-        for ((scope, keys) <- data.data; key <- keys.keys)
-          yield (ScopedKey(scope.copy(task = Zero), key), scope.task): (
-              ScopedKey[?],
-              ScopeAxis[AttributeKey[?]]
-          )
+        for
+          (scope, keys) <- data.keys.groupMap(_.scope)(_.key)
+          key <- keys
+        yield (ScopedKey(scope.copy(task = Zero), key), scope.task)
 
       val taskAxes = Relation.empty ++ taskAxesMappings
       val zero = new HashSet[ScopedKey[?]]
@@ -240,15 +239,14 @@ abstract class TestBuild {
       }
     }
     val data = Def.makeWithCompiledMap(settings)(using env.delegates, const(Nil), display)._2
-    val keys = data.allKeys((s, key) => ScopedKey(s, key))
-    val keyMap = keys.map(k => (k.key.label, k.key)).toMap[String, AttributeKey[?]]
+    val keyMap = data.keys.map(k => (k.key.label, k.key)).toMap[String, AttributeKey[?]]
     val projectsMap = env.builds.map(b => (b.uri, b.projects.map(_.id).toSet)).toMap
     val confs = for {
       b <- env.builds
       p <- b.projects
     } yield p.id -> p.configurations
     val confMap = confs.toMap
-    Structure(env, current, data, KeyIndex(keys, projectsMap, confMap), keyMap)
+    Structure(env, current, data, KeyIndex(data.keys, projectsMap, confMap), keyMap)
   }
 
   lazy val mkEnv: Gen[Env] = {
diff --git a/sbt-app/src/main/scala/sbt/Import.scala b/sbt-app/src/main/scala/sbt/Import.scala
index 669732047..bf3c0425c 100644
--- a/sbt-app/src/main/scala/sbt/Import.scala
+++ b/sbt-app/src/main/scala/sbt/Import.scala
@@ -9,6 +9,7 @@
 package sbt
 
 trait Import {
+  type Settings = Def.Settings
   type Setting[T] = Def.Setting[T]
   type ScopedKey[T] = Def.ScopedKey[T]
   type SettingsDefinition = Def.SettingsDefinition
@@ -146,7 +147,7 @@ trait Import {
   // type Dag[A <: Dag[A]] = sbt.internal.util.Dag[A]
   type DelegatingPMap[K[_], V[_]] = sbt.internal.util.DelegatingPMap[K, V]
   val ErrorHandling = sbt.internal.util.ErrorHandling
-  type EvaluateSettings[S] = sbt.internal.util.EvaluateSettings[S]
+  // type EvaluateSettings[I <: Init] = sbt.internal.util.EvaluateSettings[I]
   val EvaluationState = sbt.internal.util.EvaluationState
   val ExitHook = sbt.internal.util.ExitHook
   type ExitHook = sbt.internal.util.ExitHook
@@ -168,7 +169,7 @@ trait Import {
   type IDSet[T] = sbt.internal.util.IDSet[T]
   val IMap = sbt.internal.util.IMap
   type IMap[K[_], V[_]] = sbt.internal.util.IMap[K, V]
-  type Init[S] = sbt.internal.util.Init[S]
+  type Init = sbt.internal.util.Init
   type JLine = sbt.internal.util.JLine
   // val KCons = sbt.internal.util.KCons
   // type KCons[H, +T <: KList[M], +M[_]] = sbt.internal.util.KCons[H, T, M]
@@ -193,7 +194,6 @@ trait Import {
   val Relation = sbt.internal.util.Relation
   type Relation[A, B] = sbt.internal.util.Relation[A, B]
   val ScalaKeywords = sbt.internal.util.ScalaKeywords
-  type Settings[S] = sbt.internal.util.Settings[S]
   type SharedAttributeKey[T] = sbt.internal.util.SharedAttributeKey[T]
   val Signals = sbt.internal.util.Signals
   val SimpleReader = sbt.internal.util.SimpleReader
diff --git a/tasks-standard/src/main/scala/sbt/Task.scala b/tasks-standard/src/main/scala/sbt/Task.scala
index 099d4d10c..cbe2628d5 100644
--- a/tasks-standard/src/main/scala/sbt/Task.scala
+++ b/tasks-standard/src/main/scala/sbt/Task.scala
@@ -14,32 +14,51 @@ import ConcurrentRestrictions.{ Tag, TagMap, tagsKey }
 import sbt.util.Monad
 
 /**
- * Combines metadata `info` and a computation `work` to define a task.
+ * Combines metadata `attributes` and a computation `work` to define a task.
  */
-final case class Task[A](info: Info[A], work: Action[A]) extends TaskId[A]:
-  override def toString = info.name getOrElse ("Task(" + info + ")")
-  override def hashCode = info.hashCode
+final class Task[A](
+    val attributes: AttributeMap,
+    val post: A => AttributeMap,
+    val work: Action[A]
+) extends TaskId[A]:
+  override def toString = name.getOrElse(s"Task($attributes)")
+
+  def name: Option[String] = get(Task.Name)
+  def description: Option[String] = get(Task.Description)
+  def get[B](key: AttributeKey[B]): Option[B] = attributes.get(key)
+  def getOrElse[B](key: AttributeKey[B], default: => B): B = attributes.getOrElse(key, default)
+
+  def setName(name: String): Task[A] = set(Task.Name, name)
+  def setDescription(description: String): Task[A] = set(Task.Description, description)
+  def set[B](key: AttributeKey[B], value: B) =
+    new Task(attributes.put(key, value), post, work)
+
+  def postTransform(f: (A, AttributeMap) => AttributeMap): Task[A] =
+    new Task(attributes, a => f(a, post(a)), work)
 
   def tag(tags: Tag*): Task[A] = tagw(tags.map(t => (t, 1))*)
-  def tagw(tags: (Tag, Int)*): Task[A] = {
-    val tgs: TagMap = info.get(tagsKey).getOrElse(TagMap.empty)
+  def tagw(tags: (Tag, Int)*): Task[A] =
+    val tgs: TagMap = get(tagsKey).getOrElse(TagMap.empty)
     val value = tags.foldLeft(tgs)((acc, tag) => acc + tag)
-    val nextInfo = info.set(tagsKey, value)
-    withInfo(info = nextInfo)
-  }
-
-  def tags: TagMap = info.get(tagsKey).getOrElse(TagMap.empty)
-  def name: Option[String] = info.name
-
-  def attributes: AttributeMap = info.attributes
-
-  private[sbt] def withInfo(info: Info[A]): Task[A] =
-    Task(info = info, work = this.work)
+    set(tagsKey, value)
+  def tags: TagMap = get(tagsKey).getOrElse(TagMap.empty)
 end Task
 
 object Task:
   import sbt.std.TaskExtra.*
 
+  def apply[A](work: Action[A]): Task[A] =
+    new Task[A](AttributeMap.empty, defaultAttributeMap, work)
+
+  def apply[A](attributes: AttributeMap, work: Action[A]): Task[A] =
+    new Task[A](attributes, defaultAttributeMap, work)
+
+  def unapply[A](task: Task[A]): Option[Action[A]] = Some(task.work)
+
+  val Name = AttributeKey[String]("name")
+  val Description = AttributeKey[String]("description")
+  val defaultAttributeMap = const(AttributeMap.empty)
+
   given taskMonad: Monad[Task] with
     type F[a] = Task[a]
     override def pure[A1](a: () => A1): Task[A1] = toTask(a)
@@ -54,34 +73,3 @@ object Task:
     override def flatMap[A1, A2](in: F[A1])(f: A1 => F[A2]): F[A2] = in.flatMap(f)
     override def flatten[A1](in: Task[Task[A1]]): Task[A1] = in.flatMap(identity)
 end Task
-
-/**
- * Used to provide information about a task, such as the name, description, and tags for controlling
- * concurrent execution.
- * @param attributes
- *   Arbitrary user-defined key/value pairs describing this task
- * @param post
- *   a transformation that takes the result of evaluating this task and produces user-defined
- *   key/value pairs.
- */
-final case class Info[T](
-    attributes: AttributeMap = AttributeMap.empty,
-    post: T => AttributeMap = Info.defaultAttributeMap
-) {
-  import Info._
-  def name = attributes.get(Name)
-  def description = attributes.get(Description)
-  def setName(n: String) = set(Name, n)
-  def setDescription(d: String) = set(Description, d)
-  def set[A](key: AttributeKey[A], value: A) = copy(attributes = this.attributes.put(key, value))
-  def get[A](key: AttributeKey[A]): Option[A] = attributes.get(key)
-  def postTransform(f: (T, AttributeMap) => AttributeMap) = copy(post = (t: T) => f(t, post(t)))
-
-  override def toString = if (attributes.isEmpty) "_" else attributes.toString
-}
-
-object Info:
-  val Name = AttributeKey[String]("name")
-  val Description = AttributeKey[String]("description")
-  val defaultAttributeMap = const(AttributeMap.empty)
-end Info
diff --git a/tasks-standard/src/main/scala/sbt/std/TaskExtra.scala b/tasks-standard/src/main/scala/sbt/std/TaskExtra.scala
index 946d46b3e..c0c652bb5 100644
--- a/tasks-standard/src/main/scala/sbt/std/TaskExtra.scala
+++ b/tasks-standard/src/main/scala/sbt/std/TaskExtra.scala
@@ -103,7 +103,7 @@ trait TaskExtra0 {
     joinTasks0[Any](existToAny(in))
   private[sbt] def joinTasks0[S](in: Seq[Task[S]]): JoinTask[S, Seq] = new JoinTask[S, Seq] {
     def join: Task[Seq[S]] =
-      Task[Seq[S]](Info(), Action.Join(in, (s: Seq[Result[S]]) => Right(TaskExtra.all(s))))
+      Task[Seq[S]](Action.Join(in, (s: Seq[Result[S]]) => Right(TaskExtra.all(s))))
     def reduced(f: (S, S) => S): Task[S] = TaskExtra.reduced(in.toIndexedSeq, f)
   }
   private[sbt] def existToAny(in: Seq[Task[?]]): Seq[Task[Any]] = in.asInstanceOf[Seq[Task[Any]]]
@@ -114,8 +114,8 @@ trait TaskExtra extends TaskExtra0 {
   final def constant[T](t: T): Task[T] = task(t)
 
   final def task[T](f: => T): Task[T] = toTask(() => f)
-  final implicit def toTask[T](f: () => T): Task[T] = Task(Info(), Action.Pure(f, false))
-  final def inlineTask[T](value: T): Task[T] = Task(Info(), Action.Pure(() => value, true))
+  final implicit def toTask[T](f: () => T): Task[T] = Task(Action.Pure(f, false))
+  final def inlineTask[T](value: T): Task[T] = Task(Action.Pure(() => value, true))
 
   final implicit def upcastTask[A >: B, B](t: Task[B]): Task[A] = t mapN { x =>
     x: A
@@ -131,7 +131,7 @@ trait TaskExtra extends TaskExtra0 {
 
   final implicit def joinTasks[S](in: Seq[Task[S]]): JoinTask[S, Seq] = new JoinTask[S, Seq] {
     def join: Task[Seq[S]] =
-      Task[Seq[S]](Info(), Action.Join(in, (s: Seq[Result[S]]) => Right(TaskExtra.all(s))))
+      Task[Seq[S]](Action.Join(in, (s: Seq[Result[S]]) => Right(TaskExtra.all(s))))
     def reduced(f: (S, S) => S): Task[S] = TaskExtra.reduced(in.toIndexedSeq, f)
   }
 
@@ -144,18 +144,18 @@ trait TaskExtra extends TaskExtra0 {
   final implicit def multInputTask[Tup <: Tuple](tasks: Tuple.Map[Tup, Task]): MultiInTask[Tup] =
     new MultiInTask[Tup]:
       override def flatMapN[A](f: Tup => Task[A]): Task[A] =
-        Task(Info(), Action.FlatMapped(tasks, f.compose(allM)))
+        Task(Action.FlatMapped(tasks, f.compose(allM)))
       override def flatMapR[A](f: Tuple.Map[Tup, Result] => Task[A]): Task[A] =
-        Task(Info(), Action.FlatMapped(tasks, f))
+        Task(Action.FlatMapped(tasks, f))
 
       override def mapN[A](f: Tup => A): Task[A] =
-        Task(Info(), Action.Mapped(tasks, f.compose(allM)))
+        Task(Action.Mapped(tasks, f.compose(allM)))
       override def mapR[A](f: Tuple.Map[Tup, Result] => A): Task[A] =
-        Task(Info(), Action.Mapped(tasks, f))
+        Task(Action.Mapped(tasks, f))
       override def flatFailure[A](f: Seq[Incomplete] => Task[A]): Task[A] =
-        Task(Info(), Action.FlatMapped(tasks, f.compose(anyFailM)))
+        Task(Action.FlatMapped(tasks, f.compose(anyFailM)))
       override def mapFailure[A](f: Seq[Incomplete] => A): Task[A] =
-        Task(Info(), Action.Mapped(tasks, f.compose(anyFailM)))
+        Task(Action.Mapped(tasks, f.compose(anyFailM)))
 
   final implicit def singleInputTask[S](in: Task[S]): SingleInTask[S] =
     new SingleInTask[S]:
@@ -164,21 +164,22 @@ trait TaskExtra extends TaskExtra0 {
       def failure: Task[Incomplete] = mapFailure(identity)
       def result: Task[Result[S]] = mapR(identity)
 
-      private def newInfo[A]: Info[A] = TaskExtra.newInfo(in.info)
+      private def newAttributes: AttributeMap = TaskExtra.newAttributes(in.attributes)
 
       override def flatMapR[A](f: Result[S] => Task[A]): Task[A] =
         Task(
-          newInfo,
+          newAttributes,
           Action.FlatMapped[A, Tuple1[S]](Tuple1(in), { case Tuple1(a) => f(a) })
         )
 
       override def mapR[A](f: Result[S] => A): Task[A] =
         Task(
-          newInfo,
+          newAttributes,
           Action.Mapped[A, Tuple1[S]](Tuple1(in), { case Tuple1(a) => f(a) })
         )
 
-      override def dependsOn(tasks: Task[?]*): Task[S] = Task(newInfo, Action.DependsOn(in, tasks))
+      override def dependsOn(tasks: Task[?]*): Task[S] =
+        Task(newAttributes, Action.DependsOn(in, tasks))
 
       override def flatMapN[T](f: S => Task[T]): Task[T] = flatMapR(f.compose(successM))
 
@@ -206,8 +207,8 @@ trait TaskExtra extends TaskExtra0 {
       def &&[T](alt: Task[T]): Task[T] = flatMapN(_ => alt)
 
   final implicit def toTaskInfo[S](in: Task[S]): TaskInfo[S] = new TaskInfo[S] {
-    def describedAs(s: String): Task[S] = in.copy(info = in.info.setDescription(s))
-    def named(s: String): Task[S] = in.copy(info = in.info.setName(s))
+    def describedAs(s: String): Task[S] = in.setDescription(s)
+    def named(s: String): Task[S] = in.setName(s)
   }
 
   final implicit def pipeToProcess[Key](
@@ -327,10 +328,10 @@ object TaskExtra extends TaskExtra {
   def incompleteDeps(incs: Seq[Incomplete]): Incomplete = Incomplete(None, causes = incs)
 
   def select[A, B](fab: Task[Either[A, B]], f: Task[A => B]): Task[B] =
-    Task(newInfo(fab.info), Action.Selected[A, B](fab, f))
+    Task(newAttributes(fab.attributes), Action.Selected[A, B](fab, f))
 
   // The "taskDefinitionKey" is used, at least, by the ".previous" functionality.
   // But apparently it *cannot* survive a task map/flatMap/etc. See actions/depends-on.
-  private[sbt] def newInfo[A](info: Info[?]): Info[A] =
-    Info[A](AttributeMap(info.attributes.entries.filter(_.key.label != "taskDefinitionKey")))
+  private[sbt] def newAttributes[A](attributes: AttributeMap): AttributeMap =
+    AttributeMap(attributes.entries.filter(_.key.label != "taskDefinitionKey"))
 }
diff --git a/tasks-standard/src/main/scala/sbt/std/Transform.scala b/tasks-standard/src/main/scala/sbt/std/Transform.scala
index 134344c9c..f10d4735f 100644
--- a/tasks-standard/src/main/scala/sbt/std/Transform.scala
+++ b/tasks-standard/src/main/scala/sbt/std/Transform.scala
@@ -17,7 +17,7 @@ import sbt.internal.util.Types.*
 
 object Transform:
   def fromDummy[A](original: Task[A])(action: => A): Task[A] =
-    Task(original.info, Action.Pure(() => action, false))
+    new Task(original.attributes, original.post, work = Action.Pure(() => action, false))
 
   def fromDummyStrict[T](original: Task[T], value: T): Task[T] = fromDummy(original)(value)
 
@@ -57,8 +57,8 @@ object Transform:
         case Join(in, f)         => uniform(in)(f)
 
       def inline1[T](t: TaskId[T]): Option[() => T] = t match
-        case Task(_, Action.Pure(eval, true)) => Some(eval)
-        case _                                => None
+        case Task(Action.Pure(eval, true)) => Some(eval)
+        case _                             => None
 
   def uniform[A1, D](tasks: Seq[Task[D]])(
       f: Seq[Result[D]] => Either[Task[A1], A1]
diff --git a/util-collection/src/main/scala/sbt/internal/util/Attributes.scala b/util-collection/src/main/scala/sbt/internal/util/Attributes.scala
index f0f1412f5..4d672a905 100644
--- a/util-collection/src/main/scala/sbt/internal/util/Attributes.scala
+++ b/util-collection/src/main/scala/sbt/internal/util/Attributes.scala
@@ -158,123 +158,95 @@ object AttributeKey {
  * keys with the same label but different types. Excluding this possibility is the responsibility of
  * the client if desired.
  */
-trait AttributeMap {
-
-  /**
-   * Gets the value of type `T` associated with the key `k`. If a key with the same label but
-   * different type is defined, this method will fail.
-   */
-  def apply[T](k: AttributeKey[T]): T
-
-  /**
-   * Gets the value of type `T` associated with the key `k` or `None` if no value is associated. If
-   * a key with the same label but a different type is defined, this method will return `None`.
-   */
-  def get[T](k: AttributeKey[T]): Option[T]
-
-  /**
-   * Returns this map without the mapping for `k`. This method will not remove a mapping for a key
-   * with the same label but a different type.
-   */
-  def remove[T](k: AttributeKey[T]): AttributeMap
-
-  /**
-   * Returns true if this map contains a mapping for `k`. If a key with the same label but a
-   * different type is defined in this map, this method will return `false`.
-   */
-  def contains[T](k: AttributeKey[T]): Boolean
-
-  /**
-   * Adds the mapping `k -> value` to this map, replacing any existing mapping for `k`. Any mappings
-   * for keys with the same label but different types are unaffected.
-   */
-  def put[T](k: AttributeKey[T], value: T): AttributeMap
-
-  /**
-   * All keys with defined mappings. There may be multiple keys with the same `label`, but different
-   * types.
-   */
-  def keys: Iterable[AttributeKey[?]]
-
-  /**
-   * Adds the mappings in `o` to this map, with mappings in `o` taking precedence over existing
-   * mappings.
-   */
-  def ++(o: Iterable[AttributeEntry[?]]): AttributeMap
-
-  /**
-   * Combines the mappings in `o` with the mappings in this map, with mappings in `o` taking
-   * precedence over existing mappings.
-   */
-  def ++(o: AttributeMap): AttributeMap
-
-  /**
-   * All mappings in this map. The [[AttributeEntry]] type preserves the typesafety of mappings,
-   * although the specific types are unknown.
-   */
-  def entries: Iterable[AttributeEntry[?]]
-
-  /** `true` if there are no mappings in this map, `false` if there are. */
-  def isEmpty: Boolean
-
-  /**
-   * Adds the mapping `k -> opt.get` if opt is Some. Otherwise, it returns this map without the
-   * mapping for `k`.
-   */
-  private[sbt] def setCond[T](k: AttributeKey[T], opt: Option[T]): AttributeMap
-}
-
-object AttributeMap {
+opaque type AttributeMap = Map[AttributeKey[?], Any]
 
+object AttributeMap:
   /** An [[AttributeMap]] without any mappings. */
-  val empty: AttributeMap = new BasicAttributeMap(Map.empty)
+  val empty: AttributeMap = Map.empty
 
   /** Constructs an [[AttributeMap]] containing the given `entries`. */
-  def apply(entries: Iterable[AttributeEntry[?]]): AttributeMap = empty ++ entries
+  def apply(entries: Iterable[AttributeEntry[?]]): AttributeMap = ++(empty)(entries)
 
   /** Constructs an [[AttributeMap]] containing the given `entries`. */
-  def apply(entries: AttributeEntry[?]*): AttributeMap = empty ++ entries
+  def apply(entries: AttributeEntry[?]*): AttributeMap = ++(empty)(entries)
 
-  /** Presents an `AttributeMap` as a natural transformation. */
-  // implicit def toNatTrans(map: AttributeMap): AttributeKey ~> Id = λ[AttributeKey ~> Id](map(_))
-}
+  extension (self: AttributeMap)
+    /**
+     * Gets the value of type `T` associated with the key `k`. If a key with the same label but
+     * different type is defined, this method will fail.
+     */
+    def apply[T](k: AttributeKey[T]): T = self(k).asInstanceOf[T]
 
-private class BasicAttributeMap(private val backing: Map[AttributeKey[?], Any])
-    extends AttributeMap {
+    /**
+     * Gets the value of type `T` associated with the key `k` or `None` if no value is associated. If
+     * a key with the same label but a different type is defined, this method will return `None`.
+     */
+    def get[T](k: AttributeKey[T]): Option[T] = self.get(k).asInstanceOf[Option[T]]
 
-  def isEmpty: Boolean = backing.isEmpty
-  def apply[T](k: AttributeKey[T]) = backing(k).asInstanceOf[T]
-  def get[T](k: AttributeKey[T]) = backing.get(k).asInstanceOf[Option[T]]
-  def remove[T](k: AttributeKey[T]): AttributeMap = new BasicAttributeMap(backing - k)
-  def contains[T](k: AttributeKey[T]) = backing.contains(k)
+    /**
+     * Gets the value of type `T` associated with the key `k` or `default` if no value is associated. If
+     * a key with the same label but a different type is defined, this method will return `default`.
+     */
+    def getOrElse[T](k: AttributeKey[T], default: => T): T =
+      self.getOrElse(k, default).asInstanceOf[T]
 
-  def put[T](k: AttributeKey[T], value: T): AttributeMap =
-    new BasicAttributeMap(backing.updated(k, value: Any))
+    /**
+     * Returns this map without the mapping for `k`. This method will not remove a mapping for a key
+     * with the same label but a different type.
+     */
+    def remove[T](k: AttributeKey[T]): AttributeMap = self.removed(k)
 
-  def keys: Iterable[AttributeKey[?]] = backing.keys
+    /**
+     * Returns true if this map contains a mapping for `k`. If a key with the same label but a
+     * different type is defined in this map, this method will return `false`.
+     */
+    def contains[T](k: AttributeKey[T]): Boolean = self.contains(k)
 
-  def ++(o: Iterable[AttributeEntry[?]]): AttributeMap =
-    new BasicAttributeMap(o.foldLeft(backing)((b, e) => b.updated(e.key, e.value: Any)))
+    /**
+     * Adds the mapping `k -> value` to this map, replacing any existing mapping for `k`. Any mappings
+     * for keys with the same label but different types are unaffected.
+     */
+    def put[T](k: AttributeKey[T], value: T): AttributeMap = self.updated(k, value)
 
-  def ++(o: AttributeMap): AttributeMap = o match {
-    case bam: BasicAttributeMap =>
-      new BasicAttributeMap(Map(backing.toSeq ++ bam.backing.toSeq*))
-    case _ => o ++ this
-  }
+    /**
+     * All keys with defined mappings. There may be multiple keys with the same `label`, but different
+     * types.
+     */
+    def keys: Iterable[AttributeKey[?]] = self.keys
 
-  def entries: Iterable[AttributeEntry[?]] =
-    backing.collect { case (k: AttributeKey[kt], v) =>
-      AttributeEntry(k, v.asInstanceOf[kt])
-    }
+    /**
+     * Adds the mappings in `o` to this map, with mappings in `o` taking precedence over existing
+     * mappings.
+     */
+    def ++(o: Iterable[AttributeEntry[?]]): AttributeMap =
+      o.foldLeft(self)((b, e) => b.updated(e.key, e.value))
 
-  private[sbt] def setCond[T](k: AttributeKey[T], opt: Option[T]): AttributeMap =
-    opt match {
-      case Some(v) => put(k, v)
-      case None    => remove(k)
-    }
+    /**
+     * Combines the mappings in `o` with the mappings in this map, with mappings in `o` taking
+     * precedence over existing mappings.
+     */
+    def ++(o: AttributeMap): AttributeMap = self ++ o
 
-  override def toString = entries.mkString("(", ", ", ")")
-}
+    /**
+     * All mappings in this map. The [[AttributeEntry]] type preserves the typesafety of mappings,
+     * although the specific types are unknown.
+     */
+    def entries: Iterable[AttributeEntry[?]] =
+      self.collect { case (k: AttributeKey[x], v) => AttributeEntry(k, v.asInstanceOf[x]) }
+
+    /** `true` if there are no mappings in this map, `false` if there are. */
+    def isEmpty: Boolean = self.isEmpty
+
+    /**
+     * Adds the mapping `k -> opt.get` if opt is Some. Otherwise, it returns this map without the
+     * mapping for `k`.
+     */
+    private[sbt] def setCond[T](k: AttributeKey[T], opt: Option[T]): AttributeMap =
+      opt match
+        case Some(v) => self.updated(k, v)
+        case None    => self.removed(k)
+  end extension
+end AttributeMap
 
 /**
  * An immutable map where both key and value are String.
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 8e73edce3..1935c0346 100644
--- a/util-collection/src/main/scala/sbt/internal/util/INode.scala
+++ b/util-collection/src/main/scala/sbt/internal/util/INode.scala
@@ -20,13 +20,12 @@ enum EvaluationState:
   case Calling
   case Evaluated
 
-abstract class EvaluateSettings[ScopeType]:
-  protected val init: Init[ScopeType]
+class EvaluateSettings[I <: Init](
+    val init: I,
+    executor: Executor,
+    compiledSettings: Seq[init.Compiled[?]],
+):
   import init._
-
-  protected def executor: Executor
-  protected def compiledSettings: Seq[Compiled[?]]
-
   import EvaluationState.*
 
   private val complete = new LinkedBlockingQueue[Option[Throwable]]
@@ -68,7 +67,7 @@ abstract class EvaluateSettings[ScopeType]:
   private val running = new AtomicInteger
   private val cancel = new AtomicBoolean(false)
 
-  def run(implicit delegates: ScopeType => Seq[ScopeType]): Settings[ScopeType] = {
+  def run(implicit delegates: ScopeType => Seq[ScopeType]): Settings = {
     assert(running.get() == 0, "Already running")
     startWork()
     roots.foreach(_.registerIfNew())
@@ -83,7 +82,7 @@ abstract class EvaluateSettings[ScopeType]:
   private def getResults(implicit delegates: ScopeType => Seq[ScopeType]) =
     static.toTypedSeq.foldLeft(empty) { case (ss, static.TPair(key, node)) =>
       if key.key.isLocal then ss
-      else ss.set(key.scope, key.key, node.get)
+      else ss.set(key, node.get)
     }
 
   private lazy val getValue: [A] => INode[A] => A = [A] => (fa: INode[A]) => fa.get
diff --git a/util-collection/src/main/scala/sbt/internal/util/Settings.scala b/util-collection/src/main/scala/sbt/internal/util/Settings.scala
index d3ebec8d3..43da08b47 100644
--- a/util-collection/src/main/scala/sbt/internal/util/Settings.scala
+++ b/util-collection/src/main/scala/sbt/internal/util/Settings.scala
@@ -12,53 +12,10 @@ import sbt.util.Show
 import Util.{ nil, nilSeq }
 import scala.jdk.CollectionConverters.*
 
-sealed trait Settings[ScopeType]:
-  def data: Map[ScopeType, AttributeMap]
-  def keys(scope: ScopeType): Set[AttributeKey[?]]
-  def scopes: Set[ScopeType]
-  def definingScope(scope: ScopeType, key: AttributeKey[?]): Option[ScopeType]
-  def allKeys[A](f: (ScopeType, AttributeKey[?]) => A): Seq[A]
-  def get[A](scope: ScopeType, key: AttributeKey[A]): Option[A]
-  def getDirect[A](scope: ScopeType, key: AttributeKey[A]): Option[A]
-  def set[A](scope: ScopeType, key: AttributeKey[A], value: A): Settings[ScopeType]
-end Settings
-
-private final class Settings0[ScopeType](
-    val data: Map[ScopeType, AttributeMap],
-    val delegates: ScopeType => Seq[ScopeType]
-) extends Settings[ScopeType]:
-
-  def scopes: Set[ScopeType] = data.keySet
-  def keys(scope: ScopeType) = data(scope).keys.toSet
-
-  def allKeys[A](f: (ScopeType, AttributeKey[?]) => A): Seq[A] =
-    data.flatMap { case (scope, map) =>
-      map.keys.map(k => f(scope, k))
-    }.toSeq
-
-  def get[A](scope: ScopeType, key: AttributeKey[A]): Option[A] =
-    delegates(scope).flatMap { sc =>
-      getDirect(sc, key)
-    }.headOption
-
-  def definingScope(scope: ScopeType, key: AttributeKey[?]): Option[ScopeType] =
-    delegates(scope).find { sc =>
-      getDirect(sc, key).isDefined
-    }
-
-  def getDirect[A](scope: ScopeType, key: AttributeKey[A]): Option[A] =
-    data.get(scope).flatMap(_.get(key))
-
-  def set[A](scope: ScopeType, key: AttributeKey[A], value: A): Settings[ScopeType] =
-    val map = data.getOrElse(scope, AttributeMap.empty)
-    val newData = data.updated(scope, map.put(key, value))
-    Settings0(newData, delegates)
-
-end Settings0
-
-// delegates should contain the input Scope as the first entry
+// delegates should contain the input ScopeType as the first entry
 // this trait is intended to be mixed into an object
-trait Init[ScopeType]:
+trait Init:
+  type ScopeType
 
   /**
    * The Show instance used when a detailed String needs to be generated.
@@ -80,6 +37,58 @@ trait Init[ScopeType]:
   type ScopeLocal = ScopedKey[?] => Seq[Setting[?]]
   type MapConstant = [a] => ScopedKey[a] => Option[a]
 
+  sealed trait Settings:
+    def attributeKeys: Set[AttributeKey[?]]
+    def keys: Iterable[ScopedKey[?]]
+    def contains(key: ScopedKey[?]): Boolean
+    def values: Iterable[Any]
+    def data: Map[ScopedKey[?], Any]
+    def scopes: Set[ScopeType]
+    def getKeyValue[A](key: ScopedKey[A]): Option[(ScopedKey[A], A)]
+    def get[A](key: ScopedKey[A]): Option[A]
+    def definingKey[A](key: ScopedKey[A]): Option[ScopedKey[A]]
+    def getDirect[A](key: ScopedKey[A]): Option[A]
+    def set[A](key: ScopedKey[A], value: A): Settings
+  end Settings
+
+  private final class Settings0(
+      val scopes: Set[ScopeType],
+      val attributeKeys: Set[AttributeKey[?]],
+      // In 1.x it was a Map[Scope, AttributeMap]
+      // For the heap, it is better to store the ScopedKey[?] directly to avoid recreating
+      // abd duplicating them later.
+      val data: Map[ScopedKey[?], Any],
+      d: ScopeType => Seq[ScopeType]
+  ) extends Settings:
+    def keys: Iterable[ScopedKey[?]] = data.keys
+    def contains(key: ScopedKey[?]): Boolean = data.contains(key)
+    def values: Iterable[Any] = data.values
+
+    def get[A](key: ScopedKey[A]): Option[A] =
+      delegates(key).flatMap(data.get).nextOption.asInstanceOf[Option[A]]
+
+    def definingKey[A](key: ScopedKey[A]): Option[ScopedKey[A]] =
+      delegates(key).find(data.contains)
+
+    def getKeyValue[A](key: ScopedKey[A]): Option[(ScopedKey[A], A)] =
+      delegates(key).flatMap { k =>
+        data.get(k) match
+          case None    => None
+          case Some(v) => Some(k -> v.asInstanceOf[A])
+      }.nextOption
+
+    def getDirect[A](key: ScopedKey[A]): Option[A] = data.get(key).asInstanceOf[Option[A]]
+
+    def set[A](key: ScopedKey[A], value: A): Settings =
+      val newScopes = scopes + key.scope
+      val newAttributeKeys = attributeKeys + key.key
+      val newData = data.updated(key, value)
+      Settings0(newScopes, newAttributeKeys, newData, d)
+
+    private def delegates[A](key: ScopedKey[A]): Iterator[ScopedKey[A]] =
+      d(key.scope).iterator.map(s => key.copy(scope = s))
+  end Settings0
+
   private[sbt] abstract class ValidateKeyRef {
     def apply[T](key: ScopedKey[T], selfRefOk: Boolean): ValidatedRef[T]
   }
@@ -163,16 +172,16 @@ trait Init[ScopeType]:
   private final val nextID = new java.util.concurrent.atomic.AtomicLong
   private final def nextDefaultID(): Long = nextID.incrementAndGet()
 
-  def empty(implicit delegates: ScopeType => Seq[ScopeType]): Settings[ScopeType] =
-    Settings0(Map.empty, delegates)
+  def empty(implicit delegates: ScopeType => Seq[ScopeType]): Settings =
+    Settings0(Set.empty, Set.empty, Map.empty, delegates)
 
-  def asTransform(s: Settings[ScopeType]): [A] => ScopedKey[A] => A =
+  def asTransform(s: Settings): [A] => ScopedKey[A] => A =
     [A] => (sk: ScopedKey[A]) => getValue(s, sk)
 
-  def getValue[T](s: Settings[ScopeType], k: ScopedKey[T]) =
-    s.get(k.scope, k.key) getOrElse (throw new InvalidReference(k))
+  def getValue[T](s: Settings, k: ScopedKey[T]) =
+    s.get(k).getOrElse(throw new InvalidReference(k))
 
-  def asFunction[A](s: Settings[ScopeType]): ScopedKey[A] => A = k => getValue(s, k)
+  def asFunction[A](s: Settings): ScopedKey[A] => A = k => getValue(s, k)
 
   def mapScope(f: ScopeType => ScopeType): MapScoped =
     [a] => (k: ScopedKey[a]) => k.copy(scope = f(k.scope))
@@ -197,7 +206,7 @@ trait Init[ScopeType]:
     // inject derived settings into scopes where their dependencies are directly defined
     // and prepend per-scope settings
     val derived = deriveAndLocal(initDefaults, mkDelegates(delegates))
-    // group by Scope/Key, dropping dead initializations
+    // group by ScopeType/Key, dropping dead initializations
     val sMap: ScopedMap = grouped(derived)
     // delegate references to undefined values according to 'delegates'
     val dMap: ScopedMap =
@@ -211,13 +220,13 @@ trait Init[ScopeType]:
       delegates: ScopeType => Seq[ScopeType],
       scopeLocal: ScopeLocal,
       display: Show[ScopedKey[?]]
-  ): Settings[ScopeType] = makeWithCompiledMap(init)._2
+  ): Settings = makeWithCompiledMap(init)._2
 
   def makeWithCompiledMap(init: Seq[Setting[?]])(using
       delegates: ScopeType => Seq[ScopeType],
       scopeLocal: ScopeLocal,
       display: Show[ScopedKey[?]]
-  ): (CompiledMap, Settings[ScopeType]) =
+  ): (CompiledMap, Settings) =
     val cMap = compiled(init)(using delegates, scopeLocal, display)
     // order the initializations.  cyclic references are detected here.
     val ordered: Seq[Compiled[?]] = sort(cMap)
@@ -235,16 +244,14 @@ trait Init[ScopeType]:
   def compile(sMap: ScopedMap): CompiledMap =
     sMap match
       case m: IMap.IMap0[ScopedKey, SettingSeq] @unchecked =>
-        Par(m.backing.toVector)
+        import scala.collection.parallel.CollectionConverters.*
+        m.backing.par
           .map { case (k, ss) =>
-            val deps = ss.flatMap(_.dependencies).toSet
-            (
-              k,
-              Compiled(k.asInstanceOf[ScopedKey[Any]], deps, ss.asInstanceOf[SettingSeq[Any]])
-            )
+            val deps = ss.iterator.flatMap(_.dependencies).toSet
+            k -> Compiled(k.asInstanceOf[ScopedKey[Any]], deps, ss.asInstanceOf[SettingSeq[Any]])
           }
-          .toVector
-          .toMap
+          .to(Map)
+
       case _ =>
         sMap.toTypedSeq.map { case sMap.TPair(k, ss) =>
           val deps = ss.flatMap(_.dependencies)
@@ -324,16 +331,12 @@ trait Init[ScopeType]:
 
   private def applyInits(ordered: Seq[Compiled[?]])(implicit
       delegates: ScopeType => Seq[ScopeType]
-  ): Settings[ScopeType] =
+  ): Settings =
     val x =
       java.util.concurrent.Executors.newFixedThreadPool(Runtime.getRuntime.availableProcessors)
     try {
-      val eval: EvaluateSettings[ScopeType] = new EvaluateSettings[ScopeType] {
-        override val init: Init.this.type = Init.this
-        def compiledSettings = ordered
-        def executor = x
-      }
-      eval.run
+      val eval: EvaluateSettings[Init.this.type] = new EvaluateSettings(Init.this, x, ordered)
+      eval.run(using delegates)
     } finally {
       x.shutdown()
     }
@@ -416,15 +419,9 @@ trait Init[ScopeType]:
   final class Flattened(val key: ScopedKey[?], val dependencies: Iterable[ScopedKey[?]])
 
   def flattenLocals(compiled: CompiledMap): Map[ScopedKey[?], Flattened] = {
-    val locals = compiled flatMap { case (key, comp) =>
-      if (key.key.isLocal) Seq(comp)
-      else nilSeq[Compiled[?]]
-    }
+    val locals = compiled.collect { case (key, comp) if key.key.isLocal => comp }
     val ordered = Dag.topologicalSort(locals)(
-      _.dependencies.flatMap(dep =>
-        if (dep.key.isLocal) Seq[Compiled[?]](compiled(dep))
-        else nilSeq[Compiled[?]]
-      )
+      _.dependencies.collect { case dep if dep.key.isLocal => compiled(dep) }
     )
     def flatten(
         cmap: Map[ScopedKey[?], Flattened],
@@ -433,7 +430,7 @@ trait Init[ScopeType]:
     ): Flattened =
       new Flattened(
         key,
-        deps.flatMap(dep => if (dep.key.isLocal) cmap(dep).dependencies else Seq[ScopedKey[?]](dep))
+        deps.flatMap(dep => if (dep.key.isLocal) cmap(dep).dependencies else Seq(dep))
       )
 
     val empty = Map.empty[ScopedKey[?], Flattened]
@@ -442,10 +439,9 @@ trait Init[ScopeType]:
       cmap.updated(c.key, flatten(cmap, c.key, c.dependencies))
     }
 
-    compiled flatMap { case (key, comp) =>
-      if (key.key.isLocal) nilSeq[(ScopedKey[?], Flattened)]
-      else
-        Seq[(ScopedKey[?], Flattened)]((key, flatten(flattenedLocals, key, comp.dependencies)))
+    compiled.collect {
+      case (key, comp) if !key.key.isLocal =>
+        (key, flatten(flattenedLocals, key, comp.dependencies))
     }
   }
 
@@ -653,7 +649,7 @@ trait Init[ScopeType]:
 
     private[sbt] def validateKeyReferenced(g: ValidateKeyRef): ValidatedInit[A1]
 
-    def evaluate(map: Settings[ScopeType]): A1
+    def evaluate(map: Settings): A1
     def zip[A2](o: Initialize[A2]): Initialize[(A1, A2)] = zipTupled(o)(identity)
 
     def zipWith[A2, U](o: Initialize[A2])(f: (A1, A2) => U): Initialize[U] =
@@ -799,7 +795,7 @@ trait Init[ScopeType]:
     (fa: Initialize[A]) => (fa.mapReferenced(g))
   private def mapConstantK(g: MapConstant): [A] => Initialize[A] => Initialize[A] = [A] =>
     (fa: Initialize[A]) => (fa.mapConstant(g))
-  private def evaluateK(g: Settings[ScopeType]): [A] => Initialize[A] => A = [A] =>
+  private def evaluateK(g: Settings): [A] => Initialize[A] => A = [A] =>
     (fa: Initialize[A]) => (fa.evaluate(g))
   private def deps(ls: List[Initialize[?]]): Seq[ScopedKey[?]] =
     ls.flatMap(_.dependencies)
@@ -820,7 +816,7 @@ trait Init[ScopeType]:
       extends Keyed[S, A1]:
     override final def apply[A2](g: A1 => A2): Initialize[A2] =
       GetValue(scopedKey, g compose transform)
-    override final def evaluate(ss: Settings[ScopeType]): A1 = transform(getValue(ss, scopedKey))
+    override final def evaluate(ss: Settings): A1 = transform(getValue(ss, scopedKey))
     override final def mapReferenced(g: MapScoped): Initialize[A1] =
       GetValue(g(scopedKey), transform)
 
@@ -842,7 +838,7 @@ trait Init[ScopeType]:
   trait KeyedInitialize[A1] extends Keyed[A1, A1]:
     override final def apply[A2](g: A1 => A2): Initialize[A2] =
       GetValue(scopedKey, g)
-    override final def evaluate(ss: Settings[ScopeType]): A1 = getValue(ss, scopedKey)
+    override final def evaluate(ss: Settings): A1 = getValue(ss, scopedKey)
     override final def mapReferenced(g: MapScoped): Initialize[A1] = g(scopedKey)
 
     private[sbt] override final def validateKeyReferenced(g: ValidateKeyRef): ValidatedInit[A1] =
@@ -861,7 +857,7 @@ trait Init[ScopeType]:
     override def dependencies: Seq[ScopedKey[?]] = Nil
     override def apply[A2](g2: ([x] => Initialize[x] => Initialize[x]) => A2): Initialize[A2] =
       map(this)(g2)
-    override def evaluate(ss: Settings[ScopeType]): [x] => Initialize[x] => Initialize[x] = f
+    override def evaluate(ss: Settings): [x] => Initialize[x] => Initialize[x] = f
     override def mapReferenced(g: MapScoped): Initialize[[x] => Initialize[x] => Initialize[x]] =
       TransformCapture(mapReferencedK(g) ∙ f)
     override def mapConstant(g: MapConstant): Initialize[[x] => Initialize[x] => Initialize[x]] =
@@ -880,7 +876,7 @@ trait Init[ScopeType]:
       extends Initialize[ScopedKey[A1]]:
     override def dependencies: Seq[ScopedKey[?]] = Nil
     override def apply[A2](g2: ScopedKey[A1] => A2): Initialize[A2] = map(this)(g2)
-    override def evaluate(ss: Settings[ScopeType]): ScopedKey[A1] = key
+    override def evaluate(ss: Settings): ScopedKey[A1] = key
     override def mapReferenced(g: MapScoped): Initialize[ScopedKey[A1]] =
       ValidationCapture(g(key), selfRefOk)
     override def mapConstant(g: MapConstant): Initialize[ScopedKey[A1]] = this
@@ -898,7 +894,7 @@ trait Init[ScopeType]:
       extends Initialize[A1]:
     override def dependencies: Seq[ScopedKey[?]] = in.dependencies
     override def apply[A2](g: A1 => A2): Initialize[A2] = Bind[S, A2](s => f(s)(g), in)
-    override def evaluate(ss: Settings[ScopeType]): A1 = f(in.evaluate(ss)).evaluate(ss)
+    override def evaluate(ss: Settings): A1 = f(in.evaluate(ss)).evaluate(ss)
     override def mapReferenced(g: MapScoped) =
       Bind[S, A1](s => f(s).mapReferenced(g), in.mapReferenced(g))
 
@@ -927,7 +923,7 @@ trait Init[ScopeType]:
       case Some(i) => Right(Optional(i.validateKeyReferenced(g).toOption, f))
 
     override def mapConstant(g: MapConstant): Initialize[A1] = Optional(a map mapConstantK(g)[S], f)
-    override def evaluate(ss: Settings[ScopeType]): A1 =
+    override def evaluate(ss: Settings): A1 =
       f(a.flatMap { i => trapBadRef(evaluateK(ss)(i)) })
 
     // proper solution is for evaluate to be deprecated or for external use only and a new internal method returning Either be used
@@ -946,7 +942,7 @@ trait Init[ScopeType]:
     override def validateKeyReferenced(g: ValidateKeyRef): ValidatedInit[A1] = Right(this)
     override def apply[A2](g: A1 => A2): Initialize[A2] = Value[A2](() => g(value()))
     override def mapConstant(g: MapConstant): Initialize[A1] = this
-    override def evaluate(map: Settings[ScopeType]): A1 = value()
+    override def evaluate(map: Settings): A1 = value()
     private[sbt] override def processAttributes[A2](init: A2)(f: (A2, AttributeMap) => A2): A2 =
       init
   end Value
@@ -958,7 +954,7 @@ trait Init[ScopeType]:
       Right(this)
     override def apply[A2](g: Set[ScopeType] => A2) = map(this)(g)
     override def mapConstant(g: MapConstant): Initialize[Set[ScopeType]] = this
-    override def evaluate(map: Settings[ScopeType]): Set[ScopeType] = map.scopes
+    override def evaluate(map: Settings): Set[ScopeType] = map.scopes
     private[sbt] override def processAttributes[A2](init: A2)(f: (A2, AttributeMap) => A2): A2 =
       init
   end StaticScopes
@@ -971,7 +967,7 @@ trait Init[ScopeType]:
     override def mapConstant(g: MapConstant): Initialize[A2] =
       Uniform(f, inputs.map(_.mapConstant(g)))
     override def apply[A3](g: A2 => A3): Initialize[A3] = Uniform(g.compose(f), inputs)
-    override def evaluate(ss: Settings[ScopeType]): A2 = f(inputs.map(_.evaluate(ss)))
+    override def evaluate(ss: Settings): A2 = f(inputs.map(_.evaluate(ss)))
 
     override def validateKeyReferenced(g: ValidateKeyRef): ValidatedInit[A2] =
       val tx = inputs.map(_.validateKeyReferenced(g))
@@ -997,7 +993,7 @@ trait Init[ScopeType]:
 
     override def apply[A2](g: A1 => A2): Initialize[A2] = Apply(g compose f, inputs)
 
-    override def evaluate(ss: Settings[ScopeType]): A1 = f(inputs.unmap(evaluateK(ss)))
+    override def evaluate(ss: Settings): A1 = f(inputs.unmap(evaluateK(ss)))
 
     override def validateKeyReferenced(g: ValidateKeyRef): ValidatedInit[A1] =
       val tx: Tuple.Map[Tup, ValidatedInit] = inputs.transform(validateKeyReferencedK(g))
diff --git a/util-collection/src/test/scala-2/SettingsTest.scala b/util-collection/src/test/scala-2/SettingsTest.scala
index 00cf122fb..541431c02 100644
--- a/util-collection/src/test/scala-2/SettingsTest.scala
+++ b/util-collection/src/test/scala-2/SettingsTest.scala
@@ -191,7 +191,7 @@ object SettingsTest extends Properties("settings") {
     checkKey(chk, Some(expected), eval)
   }
 
-  def checkKey[T](key: ScopedKey[T], expected: Option[T], settings: Settings[Scope]) = {
+  def checkKey[T](key: ScopedKey[T], expected: Option[T], settings: Def.Settings) = {
     val value = settings.get(key.scope, key.key)
     ("Key: " + key) |:
       ("Value: " + value) |:
@@ -199,7 +199,7 @@ object SettingsTest extends Properties("settings") {
       (value == expected)
   }
 
-  def evaluate(settings: Seq[Setting[_]]): Settings[Scope] =
+  def evaluate(settings: Seq[Setting[_]]): Def.Settings =
     try {
       makeWithCompiledMap(settings)(delegates, scopeLocal, showFullKey)._2
     } catch {
diff --git a/util-collection/src/test/scala/SettingsExample.scala b/util-collection/src/test/scala/SettingsExample.scala
index 32ead8616..1631624cd 100644
--- a/util-collection/src/test/scala/SettingsExample.scala
+++ b/util-collection/src/test/scala/SettingsExample.scala
@@ -19,7 +19,8 @@ final case class Scope(nestIndex: Int, idAtIndex: Int = 0)
 //  Lots of type constructors would become binary, which as you may know requires lots of type lambdas
 //  when you want a type function with only one parameter.
 //  That would be a general pain.)
-case class SettingsExample() extends Init[Scope] {
+case class SettingsExample() extends Init {
+  type ScopeType = Scope
   // Provides a way of showing a Scope+AttributeKey[_]
   val showFullKey: Show[ScopedKey[?]] = Show[ScopedKey[?]]((key: ScopedKey[?]) => {
     s"${key.scope.nestIndex}(${key.scope.idAtIndex})/${key.key.label}"
@@ -64,7 +65,7 @@ case class SettingsUsage(val settingsExample: SettingsExample) {
   // "compiles" and applies the settings.
   //  This can be split into multiple steps to access intermediate results if desired.
   //  The 'inspect' command operates on the output of 'compile', for example.
-  val applied: Settings[Scope] =
+  val applied: Settings =
     makeWithCompiledMap(mySettings)(using delegates, scopeLocal, showFullKey)._2
 
   // Show results.