Suppress warnings

osu.Game/Rulesets/Configuration/IRulesetConfigManager.cs

@@ -1,11 +1,12 @@
 // 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.
 
+using System;
 using osu.Framework.Configuration.Tracking;
 
 namespace osu.Game.Rulesets.Configuration
 {
-    public interface IRulesetConfigManager : ITrackableConfigManager
+    public interface IRulesetConfigManager : ITrackableConfigManager, IDisposable
     {
     }
 }

osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs

@@ -149,8 +149,10 @@ namespace osu.Game.Rulesets.Objects.Drawables
                 return;
 
             if (HitObject.SampleControlPoint == null)
+            {
                 throw new ArgumentNullException(nameof(HitObject.SampleControlPoint), $"{nameof(HitObject)}s must always have an attached {nameof(HitObject.SampleControlPoint)}."
                                                                                       + $" This is an indication that {nameof(HitObject.ApplyDefaults)} has not been invoked on {this}.");
+            }
 
             samples = samples.Select(s => HitObject.SampleControlPoint.ApplyTo(s)).ToArray();
             foreach (var s in samples)

osu.Game/Rulesets/RulesetConfigCache.cs

@@ -43,7 +43,7 @@ namespace osu.Game.Rulesets
 
             // ensures any potential database operations are finalised before game destruction.
             foreach (var c in configCache.Values)
-                (c as IDisposable)?.Dispose();
+                c?.Dispose();
         }
     }
 }