diff --git a/osu.Game/Graphics/IHasAccentColour.cs b/osu.Game/Graphics/IHasAccentColour.cs
index 1a66819379..af497da70f 100644
--- a/osu.Game/Graphics/IHasAccentColour.cs
+++ b/osu.Game/Graphics/IHasAccentColour.cs
@@ -24,7 +24,7 @@ namespace osu.Game.Graphics
         /// </summary>
         /// <returns>A <see cref="TransformSequence{T}"/> to which further transforms can be added.</returns>
         public static TransformSequence<T> FadeAccent<T>(this T accentedDrawable, Color4 newColour, double duration = 0, Easing easing = Easing.None)
-            where T : IHasAccentColour
+            where T : class, IHasAccentColour
             => accentedDrawable.TransformTo(nameof(accentedDrawable.AccentColour), newColour, duration, easing);
 
         /// <summary>
diff --git a/osu.Game/Storyboards/Drawables/IFlippable.cs b/osu.Game/Storyboards/Drawables/IFlippable.cs
index 9e12de5833..1c4cdde22d 100644
--- a/osu.Game/Storyboards/Drawables/IFlippable.cs
+++ b/osu.Game/Storyboards/Drawables/IFlippable.cs
@@ -41,7 +41,7 @@ namespace osu.Game.Storyboards.Drawables
         /// </summary>
         /// <returns>A <see cref="TransformSequence{T}"/> to which further transforms can be added.</returns>
         public static TransformSequence<T> TransformFlipH<T>(this T flippable, bool newValue, double delay = 0)
-            where T : IFlippable
+            where T : class, IFlippable
             => flippable.TransformTo(flippable.PopulateTransform(new TransformFlipH(), newValue, delay));
 
         /// <summary>
@@ -49,7 +49,7 @@ namespace osu.Game.Storyboards.Drawables
         /// </summary>
         /// <returns>A <see cref="TransformSequence{T}"/> to which further transforms can be added.</returns>
         public static TransformSequence<T> TransformFlipV<T>(this T flippable, bool newValue, double delay = 0)
-            where T : IFlippable
+            where T : class, IFlippable
             => flippable.TransformTo(flippable.PopulateTransform(new TransformFlipV(), newValue, delay));
     }
 }