CA1825: use Array.Empty.

CodeAnalysis/osu.ruleset

@@ -57,7 +57,4 @@
     <Rule Id="CA2213" Action="None" />
     <Rule Id="CA2235" Action="None" />
   </Rules>
-  <Rules AnalyzerId="Microsoft.NetCore.CSharp.Analyzers" RuleNamespace="Microsoft.NetCore.CSharp.Analyzers">
-    <Rule Id="CA1825" Action="None" />
-  </Rules>
 </RuleSet>

osu.Game.Rulesets.Catch/CatchRuleset.cs

@@ -18,6 +18,7 @@ using osu.Game.Rulesets.Catch.Beatmaps;
 using osu.Game.Rulesets.Catch.Difficulty;
 using osu.Game.Rulesets.Difficulty;
 using osu.Game.Scoring;
+using System;
 
 namespace osu.Game.Rulesets.Catch
 {
@@ -112,7 +113,7 @@ namespace osu.Game.Rulesets.Catch
                     };
 
                 default:
-                    return new Mod[] { };
+                    return Array.Empty<Mod>();
             }
         }
 

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -158,7 +158,7 @@ namespace osu.Game.Rulesets.Mania
                     };
 
                 default:
-                    return new Mod[] { };
+                    return Array.Empty<Mod>();
             }
         }
 
@@ -268,7 +268,7 @@ namespace osu.Game.Rulesets.Mania
                     return stage1Bindings.Concat(stage2Bindings);
             }
 
-            return new KeyBinding[0];
+            return Array.Empty<KeyBinding>();
         }
 
         public override string GetVariantName(int variant)

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -26,6 +26,7 @@ using osu.Game.Rulesets.Osu.Difficulty;
 using osu.Game.Rulesets.Osu.Skinning;
 using osu.Game.Scoring;
 using osu.Game.Skinning;
+using System;
 
 namespace osu.Game.Rulesets.Osu
 {
@@ -149,7 +150,7 @@ namespace osu.Game.Rulesets.Osu
                     };
 
                 default:
-                    return new Mod[] { };
+                    return Array.Empty<Mod>();
             }
         }
 

osu.Game.Rulesets.Taiko/TaikoRuleset.cs

@@ -18,6 +18,7 @@ using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Taiko.Beatmaps;
 using osu.Game.Rulesets.Taiko.Difficulty;
 using osu.Game.Scoring;
+using System;
 
 namespace osu.Game.Rulesets.Taiko
 {
@@ -111,7 +112,7 @@ namespace osu.Game.Rulesets.Taiko
                     };
 
                 default:
-                    return new Mod[] { };
+                    return Array.Empty<Mod>();
             }
         }
 

osu.Game.Tests/Visual/Gameplay/TestSceneSkipOverlay.cs

@@ -1,6 +1,7 @@
 // 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 System.Linq;
 using NUnit.Framework;
 using osu.Framework.Graphics;
@@ -31,7 +32,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             requestCount = 0;
             increment = skip_time;
 
-            Child = gameplayClockContainer = new GameplayClockContainer(CreateWorkingBeatmap(CreateBeatmap(new OsuRuleset().RulesetInfo)), new Mod[] { }, 0)
+            Child = gameplayClockContainer = new GameplayClockContainer(CreateWorkingBeatmap(CreateBeatmap(new OsuRuleset().RulesetInfo)), Array.Empty<Mod>(), 0)
             {
                 RelativeSizeAxes = Axes.Both,
                 Children = new Drawable[]

osu.Game.Tests/Visual/Multiplayer/TestSceneMatchParticipants.cs

@@ -45,7 +45,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             });
 
             AddStep(@"set max", () => Room.MaxParticipants.Value = 10);
-            AddStep(@"clear users", () => Room.Participants.Value = new User[] { });
+            AddStep(@"clear users", () => Room.Participants.Value = System.Array.Empty<User>());
             AddStep(@"set max to null", () => Room.MaxParticipants.Value = null);
         }
     }

osu.Game.Tests/Visual/Online/TestSceneUserProfileOverlay.cs

@@ -70,7 +70,7 @@ namespace osu.Game.Tests.Visual.Online
             },
             Title = "osu!volunteer",
             Colour = "ff0000",
-            Achievements = new User.UserAchievement[0],
+            Achievements = Array.Empty<User.UserAchievement>(),
         };
 
         public TestSceneUserProfileOverlay()

osu.Game.Tests/Visual/Online/TestSceneUserProfilePreviousUsernames.cs

@@ -42,7 +42,7 @@ namespace osu.Game.Tests.Visual.Online
                 new User { PreviousUsernames = new[] { "longusername", "longerusername" } },
                 new User { PreviousUsernames = new[] { "test", "angelsim", "verylongusername" } },
                 new User { PreviousUsernames = new[] { "ihavenoidea", "howcani", "makethistext", "anylonger" } },
-                new User { PreviousUsernames = new string[0] },
+                new User { PreviousUsernames = Array.Empty<string>() },
                 null
             };
 

osu.Game.Tournament/Screens/Editors/LadderEditorScreen.cs

@@ -49,7 +49,7 @@ namespace osu.Game.Tournament.Screens.Editors
             get
             {
                 if (editorInfo == null)
-                    return new MenuItem[0];
+                    return Array.Empty<MenuItem>();
 
                 return new MenuItem[]
                 {

osu.Game.Tournament/Screens/Ladder/Components/DrawableMatchTeam.cs

@@ -192,7 +192,7 @@ namespace osu.Game.Tournament.Screens.Ladder.Components
             get
             {
                 if (editorInfo == null)
-                    return new MenuItem[0];
+                    return Array.Empty<MenuItem>();
 
                 return new MenuItem[]
                 {

osu.Game/Beatmaps/BeatmapInfo.cs

@@ -98,7 +98,7 @@ namespace osu.Game.Beatmaps
             {
                 if (string.IsNullOrEmpty(value))
                 {
-                    Bookmarks = new int[0];
+                    Bookmarks = Array.Empty<int>();
                     return;
                 }
 
@@ -111,7 +111,7 @@ namespace osu.Game.Beatmaps
         }
 
         [NotMapped]
-        public int[] Bookmarks { get; set; } = new int[0];
+        public int[] Bookmarks { get; set; } = Array.Empty<int>();
 
         public double DistanceSpacing { get; set; }
         public int BeatDivisor { get; set; }

osu.Game/Beatmaps/DummyWorkingBeatmap.cs

@@ -55,7 +55,7 @@ namespace osu.Game.Beatmaps
 
             private class DummyRuleset : Ruleset
             {
-                public override IEnumerable<Mod> GetModsFor(ModType type) => new Mod[] { };
+                public override IEnumerable<Mod> GetModsFor(ModType type) => Array.Empty<Mod>();
 
                 public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null)
                 {

osu.Game/Overlays/Mods/ModSection.cs

@@ -81,7 +81,7 @@ namespace osu.Game.Overlays.Mods
             }
         }
 
-        private ModButton[] buttons = { };
+        private ModButton[] buttons = Array.Empty<ModButton>();
 
         protected override bool OnKeyDown(KeyDownEvent e)
         {

osu.Game/Overlays/Music/PlaylistList.cs

@@ -239,7 +239,7 @@ namespace osu.Game.Overlays.Music
 
             private class ItemSearchContainer : FillFlowContainer<PlaylistItem>, IHasFilterableChildren
             {
-                public IEnumerable<string> FilterTerms => new string[] { };
+                public IEnumerable<string> FilterTerms => Array.Empty<string>();
 
                 public bool MatchingFilter
                 {

osu.Game/Overlays/UserProfileOverlay.cs

@@ -1,6 +1,7 @@
 // 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 System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
@@ -55,10 +56,7 @@ namespace osu.Game.Overlays
                     new BeatmapsSection(),
                     new KudosuSection()
                 }
-                : new ProfileSection[]
+                : Array.Empty<ProfileSection>();
-                {
-                    //new AboutSection(),
-                };
 
             tabs = new ProfileTabControl
             {

osu.Game/Rulesets/Mods/Mod.cs

@@ -64,7 +64,7 @@ namespace osu.Game.Rulesets.Mods
         /// The mods this mod cannot be enabled with.
         /// </summary>
         [JsonIgnore]
-        public virtual Type[] IncompatibleMods => new Type[] { };
+        public virtual Type[] IncompatibleMods => Array.Empty<Type>();
 
         /// <summary>
         /// Creates a copy of this <see cref="Mod"/> initialised to a default state.

osu.Game/Rulesets/Ruleset.cs

@@ -42,7 +42,7 @@ namespace osu.Game.Rulesets
         /// </summary>
         /// <param name="mods">The legacy enum which will be converted</param>
         /// <returns>An enumerable of constructed <see cref="Mod"/>s</returns>
-        public virtual IEnumerable<Mod> ConvertLegacyMods(LegacyMods mods) => new Mod[] { };
+        public virtual IEnumerable<Mod> ConvertLegacyMods(LegacyMods mods) => Array.Empty<Mod>();
 
         public ModAutoplay GetAutoplayMod() => GetAllMods().OfType<ModAutoplay>().First();
 
@@ -116,7 +116,7 @@ namespace osu.Game.Rulesets
         /// </summary>
         /// <param name="variant">A variant.</param>
         /// <returns>A list of valid <see cref="KeyBinding"/>s.</returns>
-        public virtual IEnumerable<KeyBinding> GetDefaultKeyBindings(int variant = 0) => new KeyBinding[] { };
+        public virtual IEnumerable<KeyBinding> GetDefaultKeyBindings(int variant = 0) => Array.Empty<KeyBinding>();
 
         /// <summary>
         /// Gets the name for a key binding variant. This is used for display in the settings overlay.

osu.Game/Screens/Play/SquareGraph.cs

@@ -38,7 +38,7 @@ namespace osu.Game.Screens.Play
             }
         }
 
-        private float[] calculatedValues = { }; // values but adjusted to fit the amount of columns
+        private float[] calculatedValues = Array.Empty<float>(); // values but adjusted to fit the amount of columns
 
         private int[] values;
 

osu.Game/Screens/Select/Details/FailRetryGraph.cs

@@ -27,8 +27,8 @@ namespace osu.Game.Screens.Select.Details
 
                 metrics = value;
 
-                var retries = Metrics?.Retries ?? new int[0];
+                var retries = Metrics?.Retries ?? Array.Empty<int>();
-                var fails = Metrics?.Fails ?? new int[0];
+                var fails = Metrics?.Fails ?? Array.Empty<int>();
 
                 float maxValue = fails.Any() ? fails.Zip(retries, (fail, retry) => fail + retry).Max() : 0;
                 failGraph.MaxValue = maxValue;