diff --git a/osu.Game.Rulesets.Osu/UI/AnyOrderHitPolicy.cs b/osu.Game.Rulesets.Osu/UI/AnyOrderHitPolicy.cs
index 69bd360b5e..2c6895d7ec 100644
--- a/osu.Game.Rulesets.Osu/UI/AnyOrderHitPolicy.cs
+++ b/osu.Game.Rulesets.Osu/UI/AnyOrderHitPolicy.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.UI;
@@ -14,7 +12,7 @@ namespace osu.Game.Rulesets.Osu.UI
     /// </summary>
     public class AnyOrderHitPolicy : IHitPolicy
     {
-        public IHitObjectContainer HitObjectContainer { get; set; }
+        public IHitObjectContainer HitObjectContainer { get; set; } = null!;
 
         public ClickAction CheckHittable(DrawableHitObject hitObject, double time, HitResult result) => ClickAction.Hit;
 
diff --git a/osu.Game.Rulesets.Osu/UI/LegacyHitPolicy.cs b/osu.Game.Rulesets.Osu/UI/LegacyHitPolicy.cs
index 2b6359fb46..daf498581e 100644
--- a/osu.Game.Rulesets.Osu/UI/LegacyHitPolicy.cs
+++ b/osu.Game.Rulesets.Osu/UI/LegacyHitPolicy.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Linq;
 using osu.Game.Rulesets.Objects;
@@ -22,7 +20,7 @@ namespace osu.Game.Rulesets.Osu.UI
     /// </summary>
     public class LegacyHitPolicy : IHitPolicy
     {
-        public IHitObjectContainer HitObjectContainer { get; set; }
+        public IHitObjectContainer? HitObjectContainer { get; set; }
 
         private readonly double hittableRange;
 
@@ -37,6 +35,9 @@ namespace osu.Game.Rulesets.Osu.UI
 
         public virtual ClickAction CheckHittable(DrawableHitObject hitObject, double time, HitResult result)
         {
+            if (HitObjectContainer == null)
+                throw new InvalidOperationException($"{nameof(HitObjectContainer)} should be set before {nameof(CheckHittable)} is called.");
+
             var aliveObjects = HitObjectContainer.AliveObjects.ToList();
             int index = aliveObjects.IndexOf(hitObject);
 
diff --git a/osu.Game.Rulesets.Osu/UI/StartTimeOrderedHitPolicy.cs b/osu.Game.Rulesets.Osu/UI/StartTimeOrderedHitPolicy.cs
index 6fd0b512be..2b24fb9398 100644
--- a/osu.Game.Rulesets.Osu/UI/StartTimeOrderedHitPolicy.cs
+++ b/osu.Game.Rulesets.Osu/UI/StartTimeOrderedHitPolicy.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using osu.Game.Rulesets.Objects;
@@ -23,11 +21,14 @@ namespace osu.Game.Rulesets.Osu.UI
     /// </summary>
     public class StartTimeOrderedHitPolicy : IHitPolicy
     {
-        public IHitObjectContainer HitObjectContainer { get; set; }
+        public IHitObjectContainer? HitObjectContainer { get; set; }
 
         public ClickAction CheckHittable(DrawableHitObject hitObject, double time, HitResult _)
         {
-            DrawableHitObject blockingObject = null;
+            if (HitObjectContainer == null)
+                throw new InvalidOperationException($"{nameof(HitObjectContainer)} should be set before {nameof(CheckHittable)} is called.");
+
+            DrawableHitObject? blockingObject = null;
 
             foreach (var obj in enumerateHitObjectsUpTo(hitObject.HitObject.StartTime))
             {
@@ -48,6 +49,9 @@ namespace osu.Game.Rulesets.Osu.UI
 
         public void HandleHit(DrawableHitObject hitObject)
         {
+            if (HitObjectContainer == null)
+                throw new InvalidOperationException($"{nameof(HitObjectContainer)} should be set before {nameof(HandleHit)} is called.");
+
             // Hitobjects which themselves don't block future hitobjects don't cause misses (e.g. slider ticks, spinners).
             if (!hitObjectCanBlockFutureHits(hitObject))
                 return;
@@ -75,7 +79,7 @@ namespace osu.Game.Rulesets.Osu.UI
 
         private IEnumerable<DrawableHitObject> enumerateHitObjectsUpTo(double targetTime)
         {
-            foreach (var obj in HitObjectContainer.AliveObjects)
+            foreach (var obj in HitObjectContainer!.AliveObjects)
             {
                 if (obj.HitObject.StartTime >= targetTime)
                     yield break;