Manual fixes to reduce warnings to zero

osu.Framework.Benchmarks/BenchmarkTextBuilder.cs

@@ -51,7 +51,7 @@ private class TestStore : ITexturedGlyphLookupStore
                 new CharacterGlyph(character, character, character, character, character, null),
                 new DummyRenderer().CreateTexture(1, 1));
 
-            public Task<ITexturedCharacterGlyph> GetAsync(string fontName, char character) => Task.Run(() => Get(fontName, character));
+            public Task<ITexturedCharacterGlyph?> GetAsync(string fontName, char character) => Task.Run<ITexturedCharacterGlyph?>(() => Get(fontName, character));
         }
     }
 }

osu.Framework.Tests/Visual/UserInterface/TestSceneRigidBody.cs

@@ -25,9 +25,6 @@ private float restitution
             {
                 restitutionBacking = value;
 
-                if (sim == null)
-                    return;
-
                 foreach (var d in sim.Children)
                     d.Restitution = value;
                 sim.Restitution = value;
@@ -43,9 +40,6 @@ private float friction
             {
                 frictionBacking = value;
 
-                if (sim == null)
-                    return;
-
                 foreach (var d in sim.Children)
                     d.FrictionCoefficient = value;
                 sim.FrictionCoefficient = value;

osu.Framework/Bindables/BindableDouble.cs

@@ -12,7 +12,7 @@ public BindableDouble(double defaultValue = 0)
         {
         }
 
-        public override string ToString(string format, IFormatProvider formatProvider) => base.ToString(format ?? "0.0###", formatProvider);
+        public override string ToString(string? format, IFormatProvider formatProvider) => base.ToString(format ?? "0.0###", formatProvider);
 
         protected override Bindable<double> CreateInstance() => new BindableDouble();
     }

osu.Framework/Bindables/BindableFloat.cs

@@ -12,7 +12,7 @@ public BindableFloat(float defaultValue = 0)
         {
         }
 
-        public override string ToString(string format, IFormatProvider formatProvider) => base.ToString(format ?? "0.0###", formatProvider);
+        public override string ToString(string? format, IFormatProvider formatProvider) => base.ToString(format ?? "0.0###", formatProvider);
 
         protected override Bindable<float> CreateInstance() => new BindableFloat();
     }

osu.Framework/Development/DebugUtils.cs

@@ -55,7 +55,7 @@ public static class DebugUtils
         public static bool LogPerformanceIssues { get; internal set; }
 
         // https://stackoverflow.com/a/2186634
-        private static bool isDebugAssembly(Assembly assembly) => assembly?.GetCustomAttributes(false).OfType<DebuggableAttribute>().Any(da => da.IsJITTrackingEnabled) ?? false;
+        private static bool isDebugAssembly(Assembly? assembly) => assembly?.GetCustomAttributes(false).OfType<DebuggableAttribute>().Any(da => da.IsJITTrackingEnabled) ?? false;
 
         /// <summary>
         /// Gets the entry assembly, or calling assembly otherwise.

osu.Framework/Graphics/Containers/LifetimeManagementContainer.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics.Performance;
 
 namespace osu.Framework.Graphics.Containers
@@ -136,7 +137,7 @@ private void drawableLifetimeChanged(Drawable drawable)
 
             public void Dispose()
             {
-                if (Drawable != null)
+                if (Drawable.IsNotNull())
                     Drawable.LifetimeChanged -= drawableLifetimeChanged;
             }
         }

osu.Framework/Graphics/Containers/Markdown/NotImplementedMarkdown.cs

@@ -36,7 +36,7 @@ public SpriteText CreateSpriteText()
             var text = parentTextComponent.CreateSpriteText();
             text.Colour = new Color4(255, 0, 0, 255);
             text.Font = text.Font.With(size: 21);
-            text.Text = markdownObject?.GetType() + " Not implemented.";
+            text.Text = markdownObject.GetType() + " Not implemented.";
             return text;
         }
     }

osu.Framework/Graphics/TransformSequenceExtensions.cs

@@ -8,7 +8,6 @@
 using osu.Framework.Graphics.Transforms;
 using osu.Framework.Threading;
 using System;
-using JetBrains.Annotations;
 using osu.Framework.Bindables;
 
 namespace osu.Framework.Graphics
@@ -249,7 +248,7 @@ public static TransformSequence<T> TransformSpacingTo<T>(this TransformSequence<
         /// Smoothly adjusts the value of a <see cref="Bindable{TValue}"/> over time.
         /// </summary>
         /// <returns>A <see cref="TransformSequence{T}"/> to which further transforms can be added.</returns>
-        public static TransformSequence<T> TransformBindableTo<T, TValue>(this TransformSequence<T> t, [NotNull] Bindable<TValue> bindable, TValue newValue, double duration = 0,
+        public static TransformSequence<T> TransformBindableTo<T, TValue>(this TransformSequence<T> t, Bindable<TValue> bindable, TValue newValue, double duration = 0,
                                                                           Easing easing = Easing.None)
             where T : class, ITransformable
             => t.TransformBindableTo(bindable, newValue, duration, new DefaultEasingFunction(easing));
@@ -487,7 +486,7 @@ public static TransformSequence<T> TransformSpacingTo<T, TEasing>(this Transform
         /// Smoothly adjusts the value of a <see cref="Bindable{TValue}"/> over time.
         /// </summary>
         /// <returns>A <see cref="TransformSequence{T}"/> to which further transforms can be added.</returns>
-        public static TransformSequence<T> TransformBindableTo<T, TValue, TEasing>(this TransformSequence<T> t, [NotNull] Bindable<TValue> bindable, TValue newValue, double duration, TEasing easing)
+        public static TransformSequence<T> TransformBindableTo<T, TValue, TEasing>(this TransformSequence<T> t, Bindable<TValue> bindable, TValue newValue, double duration, TEasing easing)
             where T : class, ITransformable
             where TEasing : IEasingFunction
             => t.Append(o => o.TransformBindableTo(bindable, newValue, duration, easing));

osu.Framework/Graphics/UserInterface/BasicButton.cs

@@ -15,12 +15,8 @@ public partial class BasicButton : Button
     {
         public LocalisableString Text
         {
-            get => SpriteText?.Text ?? default;
-            set
-            {
-                if (SpriteText != null)
-                    SpriteText.Text = value;
-            }
+            get => SpriteText.Text;
+            set => SpriteText.Text = value;
         }
 
         public Color4 BackgroundColour

osu.Framework/Graphics/UserInterface/MenuItem.cs

@@ -18,7 +18,7 @@ public class MenuItem
         /// <summary>
         /// The <see cref="Action"/> that is performed when this <see cref="MenuItem"/> is clicked.
         /// </summary>
-        public readonly Bindable<Action> Action = new Bindable<Action>();
+        public readonly Bindable<Action?> Action = new Bindable<Action?>();
 
         /// <summary>
         /// A list of items which are to be displayed in a sub-menu originating from this <see cref="MenuItem"/>.
@@ -48,7 +48,7 @@ protected MenuItem(Action action)
         /// </summary>
         /// <param name="text">The text to display.</param>
         /// <param name="action">The <see cref="Action"/> to perform when clicked.</param>
-        public MenuItem(LocalisableString text, Action action)
+        public MenuItem(LocalisableString text, Action? action)
             : this(text)
         {
             Action.Value = action;

osu.Framework/IO/Stores/FontStore.cs

@@ -3,13 +3,12 @@
 
 #nullable disable
 
-using osu.Framework.Graphics.Textures;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using osu.Framework.Logging;
-using System.Collections.Concurrent;
-using JetBrains.Annotations;
 using osu.Framework.Graphics.Rendering;
+using osu.Framework.Graphics.Textures;
+using osu.Framework.Logging;
 using osu.Framework.Platform;
 using osu.Framework.Text;
 
@@ -131,7 +130,6 @@ public override void RemoveStore(ITextureStore store)
             base.RemoveStore(store);
         }
 
-        [CanBeNull]
         public ITexturedCharacterGlyph Get(string fontName, char character)
         {
             var key = (fontName, character);

osu.Framework/IO/Stores/GlyphStore.cs

@@ -1,4 +1,4 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// 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
@@ -118,7 +118,6 @@ protected string GetFilenameForPage(int page)
             return $@"{AssetName}_{page.ToString().PadLeft((Font.Pages.Count - 1).ToString().Length, '0')}.png";
         }
 
-        [CanBeNull]
         public CharacterGlyph Get(char character)
         {
             if (Font == null)

osu.Framework/IO/Stores/IGlyphStore.cs

@@ -36,7 +36,7 @@ public interface IGlyphStore : IResourceStore<CharacterGlyph>
         /// </summary>
         /// <param name="character">The character to retrieve the <see cref="CharacterGlyph"/> for.</param>
         /// <returns>The <see cref="CharacterGlyph"/> containing associated spacing information for <paramref name="character"/>.</returns>
-        CharacterGlyph Get(char character);
+        CharacterGlyph? Get(char character);
 
         /// <summary>
         /// Retrieves the kerning for a pair of characters.

osu.Framework/Input/Events/FocusEvent.cs

@@ -1,7 +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.
 
-using JetBrains.Annotations;
 using osu.Framework.Graphics;
 using osu.Framework.Input.States;
 
@@ -15,8 +14,7 @@ public class FocusEvent : UIEvent
         /// <summary>
         /// The <see cref="Drawable"/> that has lost focus, or <c>null</c> if nothing was previously focused.
         /// </summary>
-        [CanBeNull]
-        public readonly Drawable PreviouslyFocused;
+        public readonly Drawable? PreviouslyFocused;
 
         public FocusEvent(InputState state, Drawable previouslyFocused)
             : base(state)

osu.Framework/Input/Events/FocusLostEvent.cs

@@ -1,7 +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.
 
-using JetBrains.Annotations;
 using osu.Framework.Graphics;
 using osu.Framework.Input.States;
 
@@ -15,8 +14,7 @@ public class FocusLostEvent : UIEvent
         /// <summary>
         /// The <see cref="Drawable"/> that will gain focus, or <c>null</c> if nothing will gain focus.
         /// </summary>
-        [CanBeNull]
-        public readonly Drawable NextFocused;
+        public readonly Drawable? NextFocused;
 
         public FocusLostEvent(InputState state, Drawable nextFocused)
             : base(state)

osu.Framework/Input/Events/JoystickAxisMoveEvent.cs

@@ -1,7 +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.
 
-using JetBrains.Annotations;
 using osu.Framework.Extensions.TypeExtensions;
 using osu.Framework.Input.States;
 
@@ -27,7 +26,7 @@ public class JoystickAxisMoveEvent : JoystickEvent
         /// </summary>
         public float Delta => Axis.Value - LastValue;
 
-        public JoystickAxisMoveEvent([NotNull] InputState state, JoystickAxis axis, float lastValue)
+        public JoystickAxisMoveEvent(InputState state, JoystickAxis axis, float lastValue)
             : base(state)
         {
             LastValue = lastValue;

osu.Framework/Input/Events/JoystickEvent.cs

@@ -3,14 +3,13 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using JetBrains.Annotations;
 using osu.Framework.Input.States;
 
 namespace osu.Framework.Input.Events
 {
     public abstract class JoystickEvent : UIEvent
     {
-        protected JoystickEvent([NotNull] InputState state)
+        protected JoystickEvent(InputState state)
             : base(state)
         {
         }

osu.Framework/Input/Events/MidiDownEvent.cs

@@ -1,14 +1,13 @@
 // 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 JetBrains.Annotations;
 using osu.Framework.Input.States;
 
 namespace osu.Framework.Input.Events
 {
     public class MidiDownEvent : MidiEvent
     {
-        public MidiDownEvent([NotNull] InputState state, MidiKey key, byte velocity)
+        public MidiDownEvent(InputState state, MidiKey key, byte velocity)
             : base(state, key, velocity)
         {
         }

osu.Framework/Input/Events/MidiEvent.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
-using JetBrains.Annotations;
 using osu.Framework.Extensions.TypeExtensions;
 using osu.Framework.Input.States;
 
@@ -28,7 +27,7 @@ public abstract class MidiEvent : UIEvent
         /// </summary>
         public IEnumerable<MidiKey> PressedKeys => CurrentState.Midi.Keys;
 
-        protected MidiEvent([NotNull] InputState state, MidiKey key, byte velocity)
+        protected MidiEvent(InputState state, MidiKey key, byte velocity)
             : base(state)
         {
             Key = key;

osu.Framework/Input/Events/MidiUpEvent.cs

@@ -1,14 +1,13 @@
 // 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 JetBrains.Annotations;
 using osu.Framework.Input.States;
 
 namespace osu.Framework.Input.Events
 {
     public class MidiUpEvent : MidiEvent
     {
-        public MidiUpEvent([NotNull] InputState state, MidiKey key)
+        public MidiUpEvent(InputState state, MidiKey key)
             : base(state, key, 0)
         {
         }

osu.Framework/Input/Events/TabletEvent.cs

@@ -2,14 +2,13 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
-using JetBrains.Annotations;
 using osu.Framework.Input.States;
 
 namespace osu.Framework.Input.Events
 {
     public abstract class TabletEvent : UIEvent
     {
-        protected TabletEvent([NotNull] InputState state)
+        protected TabletEvent(InputState state)
             : base(state)
         {
         }

osu.Framework/Input/JoystickButtonEventManager.cs

@@ -17,12 +17,7 @@ public JoystickButtonEventManager(JoystickButton button)
 
         protected override Drawable HandleButtonDown(InputState state, List<Drawable> targets) => PropagateButtonEvent(targets, new JoystickPressEvent(state, Button));
 
-        protected override void HandleButtonUp(InputState state, List<Drawable> targets)
-        {
-            if (targets == null)
-                return;
-
+        protected override void HandleButtonUp(InputState state, List<Drawable> targets) =>
             PropagateButtonEvent(targets, new JoystickReleaseEvent(state, Button));
-        }
     }
 }

osu.Framework/Input/KeyEventManager.cs

@@ -31,12 +31,7 @@ public void HandleRepeat(InputState state)
 
         protected override Drawable HandleButtonDown(InputState state, List<Drawable> targets) => PropagateButtonEvent(targets, new KeyDownEvent(state, Button));
 
-        protected override void HandleButtonUp(InputState state, List<Drawable> targets)
-        {
-            if (targets == null)
-                return;
-
+        protected override void HandleButtonUp(InputState state, List<Drawable> targets) =>
             PropagateButtonEvent(targets, new KeyUpEvent(state, Button));
-        }
     }
 }

osu.Framework/Input/MidiKeyEventManager.cs

@@ -17,12 +17,7 @@ public MidiKeyEventManager(MidiKey button)
 
         protected override Drawable HandleButtonDown(InputState state, List<Drawable> targets) => PropagateButtonEvent(targets, new MidiDownEvent(state, Button, state.Midi.Velocities[Button]));
 
-        protected override void HandleButtonUp(InputState state, List<Drawable> targets)
-        {
-            if (targets == null)
-                return;
-
+        protected override void HandleButtonUp(InputState state, List<Drawable> targets) =>
             PropagateButtonEvent(targets, new MidiUpEvent(state, Button));
-        }
     }
 }

osu.Framework/Input/SDL2WindowTextInput.cs

@@ -30,7 +30,7 @@ private void handleTextInput(string text)
             }
         }
 
-        private void handleTextEditing(string text, int selectionStart, int selectionLength)
+        private void handleTextEditing(string? text, int selectionStart, int selectionLength)
         {
             if (text == null) return;
 

osu.Framework/Input/StateChanges/ButtonInput.cs

@@ -41,7 +41,7 @@ protected ButtonInput(TButton button, bool isPressed)
         /// </remarks>
         /// <param name="current">The newer <see cref="ButtonStates{TButton}"/>.</param>
         /// <param name="previous">The older <see cref="ButtonStates{TButton}"/>.</param>
-        protected ButtonInput(ButtonStates<TButton> current, ButtonStates<TButton> previous)
+        protected ButtonInput(ButtonStates<TButton>? current, ButtonStates<TButton>? previous)
         {
             var difference = (current ?? new ButtonStates<TButton>()).EnumerateDifference(previous ?? new ButtonStates<TButton>());