diff --git a/sbt-plugin/src/main/scala/org/scalajs/sbtplugin/ScalaJSPluginInternal.scala b/sbt-plugin/src/main/scala/org/scalajs/sbtplugin/ScalaJSPluginInternal.scala
index 904b074791..3ea794b61f 100644
--- a/sbt-plugin/src/main/scala/org/scalajs/sbtplugin/ScalaJSPluginInternal.scala
+++ b/sbt-plugin/src/main/scala/org/scalajs/sbtplugin/ScalaJSPluginInternal.scala
@@ -123,7 +123,7 @@ private[sbtplugin] object ScalaJSPluginInternal {
 
       scalaJSLinkerBox in key := new CacheBox,
 
-      scalaJSLinker in key := {
+      scalaJSLinker in legacyKey := {
         val config = (scalaJSLinkerConfig in key).value
         val box = (scalaJSLinkerBox in key).value
         val linkerImpl = (scalaJSLinkerImpl in key).value
@@ -131,7 +131,7 @@ private[sbtplugin] object ScalaJSPluginInternal {
         box.ensure(linkerImpl.clearableLinker(config))
       },
 
-      scalaJSLinker in legacyKey := (scalaJSLinker in key).value,
+      scalaJSLinker in key := (scalaJSLinker in legacyKey).value,
 
       // Have `clean` reset the state of the incremental linker
       clean in (This, Zero, This) := {
@@ -140,7 +140,7 @@ private[sbtplugin] object ScalaJSPluginInternal {
         ()
       },
 
-      usesScalaJSLinkerTag in key := {
+      usesScalaJSLinkerTag in legacyKey := {
         val projectPart = thisProject.value.id
         val configPart = configuration.value.name
 
@@ -152,7 +152,7 @@ private[sbtplugin] object ScalaJSPluginInternal {
         Tags.Tag(s"uses-scalajs-linker-$projectPart-$configPart-$stagePart")
       },
 
-      usesScalaJSLinkerTag in legacyKey := (usesScalaJSLinkerTag in key).value,
+      usesScalaJSLinkerTag in key := (usesScalaJSLinkerTag in legacyKey).value,
 
       // Prevent this linker from being used concurrently
       concurrentRestrictions in Global +=
@@ -164,7 +164,7 @@ private[sbtplugin] object ScalaJSPluginInternal {
       scalaJSLinkerConfigFingerprint in key :=
         StandardConfig.fingerprint((scalaJSLinkerConfig in key).value),
 
-      moduleName in legacyKey := (moduleName in key).value,
+      moduleName in key := (moduleName in legacyKey).value,
 
       key := Def.taskDyn {
         /* It is very important that we evaluate all of those `.value`s from
@@ -309,7 +309,7 @@ private[sbtplugin] object ScalaJSPluginInternal {
       scalaJSStageSettings(Stage.FastOpt, linkJSDev, fastOptJS) ++
       scalaJSStageSettings(Stage.FullOpt, linkJSProd, fullOptJS)
   ) ++ (
-      Seq(linkJSDev, linkJSProd).map { key =>
+      Seq(fastOptJS, fullOptJS).map { key =>
         moduleName in key := {
           val configSuffix = configuration.value match {
             case Compile => ""
@@ -410,7 +410,7 @@ private[sbtplugin] object ScalaJSPluginInternal {
         ((crossTarget in fullOptJS).value /
             ((moduleName in fullOptJS).value + "-opt.js")),
 
-      scalaJSLinkerConfig in linkJSProd ~= { prevConfig =>
+      scalaJSLinkerConfig in fullOptJS ~= { prevConfig =>
         val useClosure = prevConfig.moduleKind != ModuleKind.ESModule
         prevConfig
           .withSemantics(_.optimized)
@@ -418,6 +418,9 @@ private[sbtplugin] object ScalaJSPluginInternal {
           .withCheckIR(true)  // for safety, fullOpt is slow anyways.
       },
 
+      scalaJSLinkerConfig in linkJSDev := (scalaJSLinkerConfig in fastOptJS).value,
+      scalaJSLinkerConfig in linkJSProd := (scalaJSLinkerConfig in fullOptJS).value,
+
       scalaJSLinkerResult := Def.settingDyn {
         scalaJSStage.value match {
           case Stage.FastOpt => linkJSDev
diff --git a/test-suite-linker/src/main/scala/org/scalajs/bootstrap/TestSuiteLinker.scala b/test-suite-linker/src/main/scala/org/scalajs/bootstrap/TestSuiteLinker.scala
index c62c05970a..a307b34bee 100644
--- a/test-suite-linker/src/main/scala/org/scalajs/bootstrap/TestSuiteLinker.scala
+++ b/test-suite-linker/src/main/scala/org/scalajs/bootstrap/TestSuiteLinker.scala
@@ -52,7 +52,7 @@ object QuickLinker {
 
   @JSImport("fs", "promises")
   @js.native
-  object PromisesFS extends js.Object {
+  private object PromisesFS extends js.Object {
     def writeFile(path: String, data: Uint8Array): js.Promise[Unit] = js.native
   }
 }
diff --git a/test-suite/js/src/test/scala/org/scalajs/testsuite/jsinterop/ExportsTest.scala b/test-suite/js/src/test/scala/org/scalajs/testsuite/jsinterop/ExportsTest.scala
index 2b54deecc0..d9195f45bd 100644
--- a/test-suite/js/src/test/scala/org/scalajs/testsuite/jsinterop/ExportsTest.scala
+++ b/test-suite/js/src/test/scala/org/scalajs/testsuite/jsinterop/ExportsTest.scala
@@ -1472,7 +1472,7 @@ class ExportsTest {
     }
   }
 
-  @Test def top_level_export_field_is_writiable_accross_modules(): Unit = {
+  @Test def top_level_export_field_is_writable_accross_modules(): Unit = {
     /* We write to basicVar exported above from a different object to test writing
      * of static fields accross module boundaries (when module splitting is
      * enabled).