diff --git a/project/Build.scala b/project/Build.scala
index ea56039fa401..19bb9a7c0419 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -1066,6 +1066,7 @@ object Build {
       Compile / doc / scalacOptions += "-Ydocument-synthetic-types",
       scalacOptions += "-Ycompile-scala2-library",
       scalacOptions += "-Yscala2Unpickler:never",
+      scalacOptions += "-Yno-experimental",
       scalacOptions -= "-Xfatal-warnings",
       Compile / compile / logLevel := Level.Error,
       ivyConfigurations += SourceDeps.hide,
diff --git a/scala2-library-cc/src/scala/collection/generic/IsSeq.scala b/scala2-library-cc/src/scala/collection/generic/IsSeq.scala
index 420a81d94ab4..0be512c4bec1 100644
--- a/scala2-library-cc/src/scala/collection/generic/IsSeq.scala
+++ b/scala2-library-cc/src/scala/collection/generic/IsSeq.scala
@@ -58,8 +58,8 @@ object IsSeq {
     * The helper method [[seqViewIsSeq_]] is added to make the binary compatible.
     */
   @annotation.targetName("seqViewIsSeq")
-  @annotation.publicInBinary
-  private[IsSeq] def seqViewIsSeq_[CC0[X] <: SeqView[X], A0]: IsSeq[CC0[A0]] { type A = A0; type C = View[A0] } = ???
+  // @annotation.publicInBinary private[IsSeq] // FIXME: enable when publicInBinary becomes stable
+  def seqViewIsSeq_[CC0[X] <: SeqView[X], A0]: IsSeq[CC0[A0]] { type A = A0; type C = View[A0] } = ???
   implicit inline def seqViewIsSeq[CC0[X] <: SeqView[X], A0]: IsIterable[CC0[A0]] { type A = A0; type C = View[A0] } = seqViewIsSeq_[CC0, A0].asInstanceOf
 
   /** !!! Under cc, views are not Seqs and can't use SeqOps.
@@ -67,8 +67,8 @@ object IsSeq {
     * The helper method [[stringViewIsSeq__]] is added to make the binary compatible.
     */
   @annotation.targetName("stringViewIsSeq")
-  @annotation.publicInBinary
-  private[IsSeq] val stringViewIsSeq_ : IsSeq[StringView] { type A = Char; type C = View[Char] } = ???
+  // @annotation.publicInBinary private[IsSeq] // FIXME: enable when publicInBinary becomes stable
+  val stringViewIsSeq_ : IsSeq[StringView] { type A = Char; type C = View[Char] } = ???
   inline implicit def stringViewIsSeq: IsIterable[StringView] { type A = Char; type C = View[Char] } = stringViewIsSeq_.asInstanceOf
 
   implicit val stringIsSeq: IsSeq[String] { type A = Char; type C = String } =