diff --git a/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala b/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala
index 9f346f97e742..9dcb10e15d16 100644
--- a/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala
+++ b/compiler/src/dotty/tools/dotc/config/ScalaSettings.scala
@@ -44,6 +44,7 @@ trait CommonScalaSettings { self: Settings.SettingGroup =>
   /** Other settings */
   val encoding: Setting[String] = StringSetting("-encoding", "encoding", "Specify character encoding used by source files.", Properties.sourceEncoding, aliases = List("--encoding"))
   val usejavacp: Setting[Boolean] = BooleanSetting("-usejavacp", "Utilize the java.class.path in classpath resolution.", aliases = List("--use-java-class-path"))
+  val scalajs: Setting[Boolean] = BooleanSetting("-scalajs", "Compile in Scala.js mode (requires scalajs-library.jar on the classpath).", aliases = List("--scalajs"))
 
   /** Plugin-related setting */
   val plugin: Setting[List[String]]             = MultiStringSetting  ("-Xplugin", "paths", "Load a plugin from each classpath.")
@@ -54,7 +55,7 @@ trait CommonScalaSettings { self: Settings.SettingGroup =>
   val pluginOptions: Setting[List[String]]      = MultiStringSetting  ("-P", "plugin:opt", "Pass an option to a plugin, e.g. -P:<plugin>:<opt>")
 }
 
-class ScalaSettings extends Settings.SettingGroup with CommonScalaSettings {
+trait AllScalaSettings extends CommonScalaSettings { self: Settings.SettingGroup =>
   // Keep synchronized with `classfileVersion` in `BCodeIdiomatic`
   private val minTargetVersion = 8
   private val maxTargetVersion = 17
@@ -80,7 +81,6 @@ class ScalaSettings extends Settings.SettingGroup with CommonScalaSettings {
   val feature: Setting[Boolean] = BooleanSetting("-feature", "Emit warning and location for usages of features that should be imported explicitly.", aliases = List("--feature"))
   val release: Setting[String] = ChoiceSetting("-release", "release", "Compile code with classes specific to the given version of the Java platform available on the classpath and emit bytecode for this version.", supportedReleaseVersions, "", aliases = List("--release"))
   val source: Setting[String] = ChoiceSetting("-source", "source version", "source version", List("3.0", "future", "3.0-migration", "future-migration"), "3.0", aliases = List("--source"))
-  val scalajs: Setting[Boolean] = BooleanSetting("-scalajs", "Compile in Scala.js mode (requires scalajs-library.jar on the classpath).", aliases = List("--scalajs"))
   val unchecked: Setting[Boolean] = BooleanSetting("-unchecked", "Enable additional warnings where generated code depends on assumptions.", aliases = List("--unchecked"))
   val uniqid: Setting[Boolean] = BooleanSetting("-uniqid", "Uniquely tag all identifiers in debugging output.", aliases = List("--unique-id"))
   val language: Setting[List[String]] = MultiStringSetting("-language", "feature", "Enable one or more language features.", aliases = List("--language"))
@@ -225,3 +225,5 @@ class ScalaSettings extends Settings.SettingGroup with CommonScalaSettings {
 
   val wikiSyntax: Setting[Boolean] = BooleanSetting("-Xwiki-syntax", "Retains the Scala2 behavior of using Wiki Syntax in Scaladoc.")
 }
+
+class ScalaSettings extends Settings.SettingGroup with AllScalaSettings
diff --git a/scaladoc/src/dotty/tools/scaladoc/DocContext.scala b/scaladoc/src/dotty/tools/scaladoc/DocContext.scala
index c63fbf6f315f..9f44069fece1 100644
--- a/scaladoc/src/dotty/tools/scaladoc/DocContext.scala
+++ b/scaladoc/src/dotty/tools/scaladoc/DocContext.scala
@@ -66,6 +66,9 @@ extension (r: report.type)
   def warn(m: String, e: Throwable)(using CompilerContext): Unit =
     r.warning(s"$m: ${throwableToString(e)}")
 
+  def echo(m: String)(using CompilerContext): Unit =
+    r.echo(m)
+
 case class NavigationNode(name: String, dri: DRI, nested: Seq[NavigationNode])
 
 case class DocContext(args: Scaladoc.Args, compilerContext: CompilerContext):
diff --git a/scaladoc/src/dotty/tools/scaladoc/Scaladoc.scala b/scaladoc/src/dotty/tools/scaladoc/Scaladoc.scala
index 4365e7b06198..3b9c8e9b9624 100644
--- a/scaladoc/src/dotty/tools/scaladoc/Scaladoc.scala
+++ b/scaladoc/src/dotty/tools/scaladoc/Scaladoc.scala
@@ -9,7 +9,7 @@ import collection.immutable.ArraySeq
 import java.nio.file.Files
 
 import dotty.tools.dotc.config.Settings._
-import dotty.tools.dotc.config.CommonScalaSettings
+import dotty.tools.dotc.config.{ CommonScalaSettings, AllScalaSettings }
 import dotty.tools.dotc.reporting.Reporter
 import dotty.tools.dotc.core.Contexts._
 
@@ -100,7 +100,15 @@ object Scaladoc:
       }
 
     val commonScalaSettings = (new SettingGroup with CommonScalaSettings).allSettings
-    allSettings.filter(commonScalaSettings.contains).foreach(setInGlobal)
+    val allScalaSettings = (new SettingGroup with AllScalaSettings).allSettings
+
+    val (shared, other) = allSettings
+      .filter(s => !s.isDefaultIn(summary.sstate))
+      .filter(allScalaSettings.contains)
+      .partition(commonScalaSettings.contains)
+    shared.foreach(setInGlobal)
+
+    if !other.isEmpty then report.echo(s"Skipping unused scalacOptions: ${other.map(_.name).mkString(", ")}")
 
     def parseTastyRoots(roots: String) =
       roots.split(File.pathSeparatorChar).toList.map(new File(_))
diff --git a/scaladoc/src/dotty/tools/scaladoc/ScaladocSettings.scala b/scaladoc/src/dotty/tools/scaladoc/ScaladocSettings.scala
index 119305a68ad2..8320a5d6c2f7 100644
--- a/scaladoc/src/dotty/tools/scaladoc/ScaladocSettings.scala
+++ b/scaladoc/src/dotty/tools/scaladoc/ScaladocSettings.scala
@@ -9,14 +9,14 @@ import collection.immutable.ArraySeq
 import java.nio.file.Files
 
 import dotty.tools.dotc.config.Settings._
-import dotty.tools.dotc.config.CommonScalaSettings
+import dotty.tools.dotc.config.AllScalaSettings
 import dotty.tools.scaladoc.Scaladoc._
 import dotty.tools.dotc.config.Settings.Setting.value
 import dotty.tools.dotc.config.Properties._
 import dotty.tools.dotc.config.CliCommand
 import dotty.tools.dotc.core.Contexts._
 
-class ScaladocSettings extends SettingGroup with CommonScalaSettings:
+class ScaladocSettings extends SettingGroup with AllScalaSettings:
   val unsupportedSettings = Seq(
     // Options that we like to support
     bootclasspath, extdirs, javabootclasspath, encoding, usejavacp,