Reduce error count.

osu.Desktop.Deploy/GitHubObject.cs

@@ -5,7 +5,7 @@ using Newtonsoft.Json;
 
 namespace osu.Desktop.Deploy
 {
-    internal class GitHubObject
+    public class GitHubObject
     {
         [JsonProperty(@"id")]
         public int Id;

osu.Desktop.Deploy/GitHubRelease.cs

@@ -5,7 +5,7 @@ using Newtonsoft.Json;
 
 namespace osu.Desktop.Deploy
 {
-    internal class GitHubRelease
+    public class GitHubRelease
     {
         [JsonProperty(@"id")]
         public int Id;

osu.Desktop/OsuGameDesktop.cs

@@ -76,10 +76,7 @@ namespace osu.Desktop
             if (isFile)
             {
                 var paths = ((object[])e.Data.GetData(DataFormats.FileDrop)).Select(f => f.ToString()).ToArray();
-                if (allowed_extensions.Any(ext => paths.All(p => p.EndsWith(ext))))
+                e.Effect = allowed_extensions.Any(ext => paths.All(p => p.EndsWith(ext))) ? DragDropEffects.Copy : DragDropEffects.None;
-                    e.Effect = DragDropEffects.Copy;
-                else
-                    e.Effect = DragDropEffects.None;
             }
         }
     }

osu.Game.Modes.Mania/UI/ManiaComboCounter.cs

@@ -31,7 +31,7 @@ namespace osu.Game.Modes.Mania.UI
 
             PopOutCount.Anchor = Anchor.BottomCentre;
             PopOutCount.Origin = Anchor.Centre;
-            PopOutCount.FadeColour(PopOutColor, 0);
+            PopOutCount.FadeColour(PopOutColor);
             OriginalColour = DisplayedCountSpriteText.Colour;
         }
 

osu.Game.Modes.Osu/Objects/CircularArcApproximator.cs

@@ -79,12 +79,9 @@ namespace osu.Game.Modes.Osu.Objects
             // We select the amount of points for the approximation by requiring the discrete curvature
             // to be smaller than the provided tolerance. The exact angle required to meet the tolerance
             // is: 2 * Math.Acos(1 - TOLERANCE / r)
-            if (2 * r <= tolerance)
+            // The special case is required for extremely short sliders where the radius is smaller than
-                // This special case is required for extremely short sliders where the radius is smaller than
+            // the tolerance. This is a pathological rather than a realistic case.
-                // the tolerance. This is a pathological rather than a realistic case.
+            amountPoints = 2 * r <= tolerance ? 2 : Math.Max(2, (int)Math.Ceiling(thetaRange / (2 * Math.Acos(1 - tolerance / r))));
-                amountPoints = 2;
-            else
-                amountPoints = Math.Max(2, (int)Math.Ceiling(thetaRange / (2 * Math.Acos(1 - tolerance / r))));
 
             List<Vector2> output = new List<Vector2>(amountPoints);
 

osu.Game.Modes.Osu/Objects/Drawables/Connections/FollowPointRenderer.cs

@@ -1,12 +1,11 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using OpenTK;
-using osu.Game.Modes.Osu.Objects.Drawables.Connections;
 using System;
 using System.Collections.Generic;
+using OpenTK;
 
-namespace osu.Game.Modes.Osu.Objects.Drawables
+namespace osu.Game.Modes.Osu.Objects.Drawables.Connections
 {
     public class FollowPointRenderer : ConnectionRenderer<OsuHitObject>
     {

osu.Game.Modes.Osu/Objects/OsuHitObjectParser.cs

@@ -34,11 +34,11 @@ namespace osu.Game.Modes.Osu.Objects
                     List<Vector2> points = new List<Vector2> { new Vector2(int.Parse(split[0]), int.Parse(split[1])) };
 
                     string[] pointsplit = split[5].Split('|');
-                    for (int i = 0; i < pointsplit.Length; i++)
+                    foreach (string t in pointsplit)
                     {
-                        if (pointsplit[i].Length == 1)
+                        if (t.Length == 1)
                         {
-                            switch (pointsplit[i])
+                            switch (t)
                             {
                                 case @"C":
                                     curveType = CurveTypes.Catmull;
@@ -56,7 +56,7 @@ namespace osu.Game.Modes.Osu.Objects
                             continue;
                         }
 
-                        string[] temp = pointsplit[i].Split(':');
+                        string[] temp = t.Split(':');
                         Vector2 v = new Vector2(
                             (int)Convert.ToDouble(temp[0], CultureInfo.InvariantCulture),
                             (int)Convert.ToDouble(temp[1], CultureInfo.InvariantCulture)

osu.Game/IO/Legacy/SerializationReader.cs

@@ -173,9 +173,11 @@ namespace osu.Game.IO.Legacy
             private static void initialize()
             {
                 versionBinder = new VersionConfigToNamespaceAssemblyObjectBinder();
-                formatter = new BinaryFormatter();
+                formatter = new BinaryFormatter
-                formatter.AssemblyFormat = FormatterAssemblyStyle.Simple;
+                {
-                formatter.Binder = versionBinder;
+                    AssemblyFormat = FormatterAssemblyStyle.Simple,
+                    Binder = versionBinder
+                };
             }
 
             public static object Deserialize(Stream stream)

osu.Game/IO/Legacy/SerializationWriter.cs

@@ -73,13 +73,16 @@ namespace osu.Game.IO.Legacy
             }
         }
 
-        /// <summary> Writes a DateTime to the buffer. <summary>
+        /// <summary>
+        /// Writes DateTime to the buffer.
+        /// </summary>
+        /// <param name="dt"></param>
         public void Write(DateTime dt)
         {
             Write(dt.ToUniversalTime().Ticks);
         }
 
-        /// <summary> Writes a generic ICollection (such as an IList<T>) to the buffer. </summary>
+        /// <summary> Writes a generic ICollection (such as an IList(T)) to the buffer.</summary>
         public void Write<T>(List<T> c) where T : ILegacySerializable
         {
             if (c == null)
@@ -212,9 +215,11 @@ namespace osu.Game.IO.Legacy
 
                     default:
                         Write((byte)ObjType.otherType);
-                        BinaryFormatter b = new BinaryFormatter();
+                        BinaryFormatter b = new BinaryFormatter
-                        b.AssemblyFormat = FormatterAssemblyStyle.Simple;
+                        {
-                        b.TypeFormat = FormatterTypeStyle.TypesWhenNeeded;
+                            AssemblyFormat = FormatterAssemblyStyle.Simple,
+                            TypeFormat = FormatterTypeStyle.TypesWhenNeeded
+                        };
                         b.Serialize(BaseStream, obj);
                         break;
                 } // switch

osu.Game/IPC/BeatmapIPCChannel.cs

@@ -16,7 +16,7 @@ namespace osu.Game.IPC
             : base(host)
         {
             this.beatmaps = beatmaps;
-            MessageReceived += (msg) =>
+            MessageReceived += msg =>
             {
                 Debug.Assert(beatmaps != null);
                 ImportAsync(msg.Path);

osu.Game/IPC/ScoreIPCChannel.cs

@@ -16,10 +16,13 @@ namespace osu.Game.IPC
             : base(host)
         {
             this.scores = scores;
-            MessageReceived += (msg) =>
+            MessageReceived += msg =>
             {
                 Debug.Assert(scores != null);
-                ImportAsync(msg.Path);
+                ImportAsync(msg.Path).ContinueWith(t =>
+                {
+                    if (t.Exception != null) throw t.Exception;
+                }, TaskContinuationOptions.OnlyOnFaulted);
             };
         }
 

osu.Game/Modes/LegacyReplay.cs

@@ -253,7 +253,7 @@ namespace osu.Game.Modes
 
             public void ReadFromStream(SerializationReader sr)
             {
-                throw new System.NotImplementedException();
+                throw new NotImplementedException();
             }
 
             public void WriteToStream(SerializationWriter sw)

osu.Game/Modes/UI/ComboCounter.cs

@@ -134,19 +134,11 @@ namespace osu.Game.Modes.UI
             updateCount(Count);
         }
 
-        /// <summary>
-        /// Animates roll-back to 0.
-        /// </summary>
-        public void Roll()
-        {
-            Roll(0);
-        }
-
         /// <summary>
         /// Animates roll-up/roll-back to an specific value.
         /// </summary>
         /// <param name="newValue">Target value.</param>
-        public virtual void Roll(ulong newValue)
+        public virtual void Roll(ulong newValue = 0)
         {
             updateCount(newValue, true);
         }

osu.Game/Online/API/APIRequest.cs

@@ -89,5 +89,5 @@ namespace osu.Game.Online.API
 
     public delegate void APIFailureHandler(Exception e);
     public delegate void APISuccessHandler();
-    public delegate void APISuccessHandler<T>(T content);
+    public delegate void APISuccessHandler<in T>(T content);
 }

osu.Game/Overlays/Mods/ModSelectOverlay.cs

@@ -167,7 +167,7 @@ namespace osu.Game.Overlays.Mods
             // 1.05x
             // 1.20x
 
-            multiplierLabel.Text = string.Format("{0:N2}x", multiplier);
+            multiplierLabel.Text = $"{multiplier:N2}x";
             string rankedString = ranked ? "Ranked" : "Unranked";
             rankedLabel.Text = $@"{rankedString}, Score Multiplier: ";
 

osu.Game/Overlays/Options/OptionDropDown.cs

@@ -39,7 +39,7 @@ namespace osu.Game.Overlays.Options
                 bindable.ValueChanged += bindable_ValueChanged;
                 bindable_ValueChanged(null, null);
 
-                if (bindable?.Disabled ?? true)
+                if ((bool)bindable?.Disabled)
                     Alpha = 0.3f;
             }
         }

osu.Game/Overlays/Toolbar/ToolbarModeSelector.cs

@@ -64,11 +64,8 @@ namespace osu.Game.Overlays.Toolbar
                 }
             };
 
-            int amountButtons = 0;
             foreach (PlayMode m in Enum.GetValues(typeof(PlayMode)))
             {
-                ++amountButtons;
-
                 var localMode = m;
                 modeButtons.Add(new ToolbarModeButton
                 {

osu.Game/Overlays/Toolbar/ToolbarUserButton.cs

@@ -94,11 +94,7 @@ namespace osu.Game.Overlays.Toolbar
 
                     userId = value;
 
-                    Sprite newSprite;
+                    var newSprite = userId > 1 ? new OnlineSprite($@"https://a.ppy.sh/{userId}") : new Sprite { Texture = guestTexture };
-                    if (userId > 1)
-                        newSprite = new OnlineSprite($@"https://a.ppy.sh/{userId}");
-                    else
-                        newSprite = new Sprite { Texture = guestTexture };
 
                     newSprite.FillMode = FillMode.Fit;
 

osu.Game/Screens/Backgrounds/BackgroundScreenBeatmap.cs

@@ -30,11 +30,7 @@ namespace osu.Game.Screens.Backgrounds
 
                 Schedule(() =>
                 {
-                    Background newBackground;
+                    var newBackground = beatmap == null ? new Background(@"Backgrounds/bg1") : new BeatmapBackground(beatmap);
-                    if (beatmap == null)
-                        newBackground = new Background(@"Backgrounds/bg1");
-                    else
-                        newBackground = new BeatmapBackground(beatmap);
 
                     newBackground.LoadAsync(Game, delegate
                     {

osu.Game/Screens/GameScreenWhiteBox.cs

@@ -25,7 +25,6 @@ namespace osu.Game.Screens
 
         protected virtual IEnumerable<Type> PossibleChildren => null;
 
-        private FillFlowContainer childModeButtons;
         private Container textContainer;
         private Box box;
 
@@ -80,6 +79,8 @@ namespace osu.Game.Screens
 
         public ScreenWhiteBox()
         {
+            FillFlowContainer childModeButtons;
+
             Children = new Drawable[]
             {
                 box = new Box

osu.Game/Screens/Menu/Button.cs

@@ -234,9 +234,7 @@ namespace osu.Game.Screens.Menu
         [BackgroundDependencyLoader]
         private void load(AudioManager audio)
         {
-            sampleClick = audio.Sample.Get($@"Menu/menu-{internalName}-click");
+            sampleClick = audio.Sample.Get($@"Menu/menu-{internalName}-click") ?? audio.Sample.Get(internalName.Contains(@"back") ? @"Menu/menuback" : @"Menu/menuhit");
-            if (sampleClick == null)
-                sampleClick = audio.Sample.Get(internalName.Contains(@"back") ? @"Menu/menuback" : @"Menu/menuhit");
         }
 
         protected override bool OnMouseDown(InputState state, MouseDownEventArgs args)

osu.Game/Screens/Menu/ButtonSystem.cs

@@ -19,7 +19,7 @@ using OpenTK.Input;
 
 namespace osu.Game.Screens.Menu
 {
-    public partial class ButtonSystem : Container, IStateful<MenuState>
+    public class ButtonSystem : Container, IStateful<MenuState>
     {
         public Action OnEdit;
         public Action OnExit;

osu.Game/Screens/Play/KeyCounter.cs

@@ -53,7 +53,7 @@ namespace osu.Game.Screens.Play
         //further: change default values here and in KeyCounterCollection if needed, instead of passing them in every constructor
         public Color4 KeyDownTextColor { get; set; } = Color4.DarkGray;
         public Color4 KeyUpTextColor { get; set; } = Color4.White;
-        public int FadeTime { get; set; } = 0;
+        public int FadeTime { get; set; }
 
         protected KeyCounter(string name)
         {

osu.Game/Screens/Play/PauseOverlay.cs

@@ -50,7 +50,7 @@ namespace osu.Game.Screens.Play
                         },
                         new OsuSpriteText
                         {
-                            Text = String.Format("{0:n0}", value),
+                            Text = $"{value:n0}",
                             Font = @"Exo2.0-Bold",
                             Shadow = true,
                             ShadowColour = new Color4(0, 0, 0, 0.25f),

osu.Game/Screens/Play/Player.cs

@@ -58,7 +58,7 @@ namespace osu.Game.Screens.Play
         private PauseOverlay pauseOverlay;
 
         [BackgroundDependencyLoader]
-        private void load(AudioManager audio, BeatmapDatabase beatmaps, OsuGameBase game, OsuConfigManager config)
+        private void load(AudioManager audio, BeatmapDatabase beatmaps, OsuConfigManager config)
         {
             var beatmap = Beatmap.Beatmap;
 

osu.Game/Screens/Select/FilterControl.cs

@@ -9,7 +9,6 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Primitives;
 using osu.Framework.Graphics.Sprites;
-using osu.Framework.Graphics.UserInterface;
 using osu.Framework.Input;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
@@ -60,7 +59,7 @@ namespace osu.Game.Screens.Select
                     {
                         searchTextBox = new SearchTextBox {
                             RelativeSizeAxes = Axes.X,
-                            OnChange = (TextBox sender, bool newText) =>
+                            OnChange = (sender, newText) =>
                             {
                                 if (newText)
                                     FilterChanged?.Invoke();

osu.Game/Screens/Select/Footer.cs

@@ -95,7 +95,7 @@ namespace osu.Game.Screens.Select
                 {
                     Anchor = Anchor.BottomLeft,
                     Origin = Anchor.BottomLeft,
-                    Position = new Vector2(BackButton.SIZE_EXTENDED.X + padding, 0),
+                    Position = new Vector2(TwoLayerButton.SIZE_EXTENDED.X + padding, 0),
                     RelativeSizeAxes = Axes.Y,
                     AutoSizeAxes = Axes.X,
                     Direction = FillDirection.Horizontal,

osu.Game/Screens/Select/PlaySongSelect.cs

@@ -341,7 +341,7 @@ namespace osu.Game.Screens.Select
 
             //todo: change background in selectionChanged instead; support per-difficulty backgrounds.
             changeBackground(beatmap);
-            carousel.SelectBeatmap(beatmap?.BeatmapInfo);
+            carousel.SelectBeatmap(beatmap.BeatmapInfo);
         }
 
         /// <summary>

osu.Game/Screens/Tournament/Drawings.cs

@@ -267,10 +267,7 @@ namespace osu.Game.Screens.Tournament
                 }
             };
 
-            if (writeOp == null)
+            writeOp = writeOp?.ContinueWith(t => { writeAction(); }) ?? Task.Run(writeAction);
-                writeOp = Task.Run(writeAction);
-            else
-                writeOp = writeOp.ContinueWith(t => { writeAction(); });
         }
 
         private void reloadTeams()

osu.Game/Screens/Tournament/ScrollingTeamContainer.cs

@@ -263,9 +263,9 @@ namespace osu.Game.Screens.Tournament
 
         private void addFlags()
         {
-            for (int i = 0; i < availableTeams.Count; i++)
+            foreach (Team t in availableTeams)
             {
-                Add(new ScrollingTeam(availableTeams[i])
+                Add(new ScrollingTeam(t)
                 {
                     X = leftPos + DrawWidth
                 });