diff --git a/packages/flutter/lib/src/rendering/binding.dart b/packages/flutter/lib/src/rendering/binding.dart
index df810c00bf..c59267961a 100644
--- a/packages/flutter/lib/src/rendering/binding.dart
+++ b/packages/flutter/lib/src/rendering/binding.dart
@@ -827,7 +827,7 @@ class _BindingPipelineManifold extends ChangeNotifier implements PipelineManifol
 }
 
 // A [PipelineOwner] that cannot have a root node.
-class _DefaultRootPipelineOwner extends PipelineOwner {
+final class _DefaultRootPipelineOwner extends PipelineOwner {
   _DefaultRootPipelineOwner() : super(onSemanticsUpdate: _onSemanticsUpdate);
 
   @override
diff --git a/packages/flutter/lib/src/rendering/object.dart b/packages/flutter/lib/src/rendering/object.dart
index ea4a837f0c..5eae165bdf 100644
--- a/packages/flutter/lib/src/rendering/object.dart
+++ b/packages/flutter/lib/src/rendering/object.dart
@@ -961,7 +961,7 @@ class _LocalSemanticsHandle implements SemanticsHandle {
 /// without tying it to a specific binding implementation. All [PipelineOwner]s
 /// in a given tree must be attached to the same [PipelineManifold]. This
 /// happens automatically during [adoptChild].
-class PipelineOwner with DiagnosticableTreeMixin {
+base class PipelineOwner with DiagnosticableTreeMixin {
   /// Creates a pipeline owner.
   ///
   /// Typically created by the binding (e.g., [RendererBinding]), but can be
diff --git a/packages/flutter/test/rendering/multi_view_binding_test.dart b/packages/flutter/test/rendering/multi_view_binding_test.dart
index 9993ab78b1..c6e5dab6f1 100644
--- a/packages/flutter/test/rendering/multi_view_binding_test.dart
+++ b/packages/flutter/test/rendering/multi_view_binding_test.dart
@@ -200,7 +200,7 @@ class FakeFlutterView extends Fake implements FlutterView {
   }
 }
 
-class PipelineOwnerSpy extends PipelineOwner {
+final class PipelineOwnerSpy extends PipelineOwner {
   @override
   final SemanticsOwnerSpy semanticsOwner = SemanticsOwnerSpy();
 }