diff --git a/project/MimaFilters.scala b/project/MimaFilters.scala
index e7351aa1b6d5..caf812cfbf1a 100644
--- a/project/MimaFilters.scala
+++ b/project/MimaFilters.scala
@@ -10,6 +10,7 @@ object MimaFilters extends AutoPlugin {
   object autoImport {
     val mimaReferenceVersion = settingKey[Option[String]]("Scala version number to run MiMa against")
   }
+
   import autoImport._
 
   override val globalSettings = Seq(
@@ -43,6 +44,10 @@ object MimaFilters extends AutoPlugin {
     ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors"),
     ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors$"),
 
+    //ADD: Await#CompletedFuture is not a public API
+    ProblemFilters.exclude[MissingClassProblem]("scala.concurrent.Await$CompletedFuture$"),
+    ProblemFilters.exclude[MissingClassProblem]("scala.collection.generic.CommonErrors$"),
+
     // scala/scala#10937
     ProblemFilters.exclude[IncompatibleResultTypeProblem]("scala.collection.immutable.LazyList#LazyBuilder#DeferredState.eval"),
     ProblemFilters.exclude[MissingClassProblem](s"scala.collection.immutable.LazyList$$State"),
@@ -82,9 +87,9 @@ object MimaFilters extends AutoPlugin {
   )
 
   val mimaSettings: Seq[Setting[_]] = Def.settings(
-    mimaPreviousArtifacts       := mimaReferenceVersion.value.map(organization.value % name.value % _).toSet,
-    mimaCheckDirection          := "both",
-    mimaBinaryIssueFilters     ++= mimaFilters,
-//  mimaReportSignatureProblems := true, // TODO: enable
+    mimaPreviousArtifacts := mimaReferenceVersion.value.map(organization.value % name.value % _).toSet,
+    mimaCheckDirection := "both",
+    mimaBinaryIssueFilters ++= mimaFilters,
+    //  mimaReportSignatureProblems := true, // TODO: enable
   )
 }
diff --git a/src/library/scala/concurrent/package.scala b/src/library/scala/concurrent/package.scala
index d648a1c90a15..3dbbc4508957 100644
--- a/src/library/scala/concurrent/package.scala
+++ b/src/library/scala/concurrent/package.scala
@@ -125,6 +125,9 @@ package object concurrent {
 }
 
 package concurrent {
+
+  import scala.util.Try
+
   /**
    * This marker trait is used by [[Await]] to ensure that [[Awaitable.ready]] and [[Awaitable.result]]
    * are not directly called by user code. An implicit instance of this trait is only available when
@@ -170,7 +173,7 @@ package concurrent {
     @throws(classOf[TimeoutException])
     @throws(classOf[InterruptedException])
     final def ready[T](awaitable: Awaitable[T], atMost: Duration): awaitable.type = awaitable match {
-      case f: Future[T] if f.isCompleted => awaitable.ready(atMost)(AwaitPermission)
+      case f: Future[T] if f.isCompleted => awaitable
       case _ => blocking(awaitable.ready(atMost)(AwaitPermission))
     }
 
@@ -197,8 +200,12 @@ package concurrent {
     @throws(classOf[TimeoutException])
     @throws(classOf[InterruptedException])
     final def result[T](awaitable: Awaitable[T], atMost: Duration): T = awaitable match {
-      case f: Future[T] if f.isCompleted => f.result(atMost)(AwaitPermission)
+      case CompletedFuture(result) => result.get.asInstanceOf[T]
       case _ => blocking(awaitable.result(atMost)(AwaitPermission))
     }
+
+    private[this] object CompletedFuture {
+      def unapply[T](f: Future[T]): Option[Try[T]] = f.value
+    }
   }
 }