From 2233327096c33a77ca497458e0ae4239cf55883e Mon Sep 17 00:00:00 2001
From: Dan Balasescu <smoogipoo@smgi.me>
Date: Fri, 27 May 2022 17:52:35 +0900
Subject: [PATCH 1/2] Add IsNull()/IsNotNull() helper extensions

---
 .../ObjectExtensions/ObjectExtensions.cs           | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs b/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs
index cc3437c311..2ea9499790 100644
--- a/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs
+++ b/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs
@@ -1,10 +1,10 @@
 // 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.Diagnostics;
-
 #nullable enable
 
+using System.Diagnostics;
+
 namespace osu.Framework.Extensions.ObjectExtensions
 {
     /// <summary>
@@ -27,5 +27,15 @@ public static T AsNonNull<T>(this T? obj)
             Debug.Assert(obj != null);
             return obj;
         }
+
+        /// <summary>
+        /// If the given object is null.
+        /// </summary>
+        public static bool IsNull<T>(this T obj) => ReferenceEquals(obj, null);
+
+        /// <summary>
+        /// <c>true</c> if the given object is not null, <c>false</c> otherwise.
+        /// </summary>
+        public static bool IsNotNull<T>(this T obj) => !ReferenceEquals(obj, null);
     }
 }

From 1f7270482ce3fe7d69389c3de1ba4cd80ed3157f Mon Sep 17 00:00:00 2001
From: Dan Balasescu <smoogipoo@smgi.me>
Date: Fri, 27 May 2022 18:10:47 +0900
Subject: [PATCH 2/2] Annotate return value for consumers

---
 .../Extensions/ObjectExtensions/ObjectExtensions.cs          | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs b/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs
index 2ea9499790..b7f698ff3a 100644
--- a/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs
+++ b/osu.Framework/Extensions/ObjectExtensions/ObjectExtensions.cs
@@ -4,6 +4,7 @@
 #nullable enable
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 
 namespace osu.Framework.Extensions.ObjectExtensions
 {
@@ -31,11 +32,11 @@ public static T AsNonNull<T>(this T? obj)
         /// <summary>
         /// If the given object is null.
         /// </summary>
-        public static bool IsNull<T>(this T obj) => ReferenceEquals(obj, null);
+        public static bool IsNull<T>([NotNullWhen(false)] this T obj) => ReferenceEquals(obj, null);
 
         /// <summary>
         /// <c>true</c> if the given object is not null, <c>false</c> otherwise.
         /// </summary>
-        public static bool IsNotNull<T>(this T obj) => !ReferenceEquals(obj, null);
+        public static bool IsNotNull<T>([NotNullWhen(true)] this T obj) => !ReferenceEquals(obj, null);
     }
 }