Fixed unnecessary zero-length array allocations

Changed all currently present zero-length array allocations in the codebase to use `Array.Empty` instead.

OpenRA.Game/Graphics/HardwarePalette.cs

@@ -24,8 +24,8 @@ namespace OpenRA.Graphics
 		readonly Dictionary<string, ImmutablePalette> palettes = new Dictionary<string, ImmutablePalette>();
 		readonly Dictionary<string, MutablePalette> mutablePalettes = new Dictionary<string, MutablePalette>();
 		readonly Dictionary<string, int> indices = new Dictionary<string, int>();
-		byte[] buffer = new byte[0];
-		float[] colorShiftBuffer = new float[0];
+		byte[] buffer = Array.Empty<byte>();
+		float[] colorShiftBuffer = Array.Empty<float>();
 
 		public HardwarePalette()
 		{

OpenRA.Game/Graphics/SpriteRenderable.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using OpenRA.Primitives;
 
@@ -16,7 +17,7 @@ namespace OpenRA.Graphics
 {
 	public class SpriteRenderable : IPalettedRenderable, IModifyableRenderable, IFinalizedRenderable
 	{
-		public static readonly IEnumerable<IRenderable> None = new IRenderable[0];
+		public static readonly IEnumerable<IRenderable> None = Array.Empty<IRenderable>();
 
 		readonly Sprite sprite;
 		readonly WPos pos;

OpenRA.Game/Map/MapPreview.cs

@@ -370,11 +370,11 @@ namespace OpenRA
 					newData.SpawnPoints = spawns.ToArray();
 				}
 				else
-					newData.SpawnPoints = new CPos[0];
+					newData.SpawnPoints = Array.Empty<CPos>();
 			}
 			catch (Exception)
 			{
-				newData.SpawnPoints = new CPos[0];
+				newData.SpawnPoints = Array.Empty<CPos>();
 				newData.Status = MapStatus.Unavailable;
 			}
 

OpenRA.Game/Primitives/TypeDictionary.cs

@@ -77,7 +77,7 @@ namespace OpenRA.Primitives
 		{
 			if (data.TryGetValue(typeof(T), out var objs))
 				return objs.Cast<T>();
-			return new T[0];
+			return Array.Empty<T>();
 		}
 
 		public void Remove<T>(T val)

OpenRA.Game/Scripting/ScriptContext.cs

@@ -279,7 +279,7 @@ namespace OpenRA.Scripting
 			return outer.SelectMany(i => i.GetGenericArguments());
 		}
 
-		static readonly object[] NoArguments = new object[0];
+		static readonly object[] NoArguments = Array.Empty<object>();
 		Type[] FilterActorCommands(ActorInfo ai)
 		{
 			return FilterCommands(ai, knownActorCommands);

OpenRA.Game/StreamExts.cs

@@ -229,7 +229,7 @@ namespace OpenRA
 			if (!string.IsNullOrEmpty(text))
 				bytes = encoding.GetBytes(text);
 			else
-				bytes = new byte[0];
+				bytes = Array.Empty<byte>();
 
 			s.Write(bytes.Length);
 			s.WriteArray(bytes);

OpenRA.Game/Traits/Player/FrozenActorLayer.cs

@@ -72,8 +72,8 @@ namespace OpenRA.Traits
 
 		public Polygon MouseBounds = Polygon.Empty;
 
-		static readonly IRenderable[] NoRenderables = new IRenderable[0];
-		static readonly Rectangle[] NoBounds = new Rectangle[0];
+		static readonly IRenderable[] NoRenderables = Array.Empty<IRenderable>();
+		static readonly Rectangle[] NoBounds = Array.Empty<Rectangle>();
 
 		int flashTicks;
 		TintModifiers flashModifiers;

OpenRA.Game/Traits/World/ScreenMap.cs

@@ -41,7 +41,7 @@ namespace OpenRA.Traits
 
 	public class ScreenMap : IWorldLoaded
 	{
-		static readonly IEnumerable<FrozenActor> NoFrozenActors = new FrozenActor[0];
+		static readonly IEnumerable<FrozenActor> NoFrozenActors = Array.Empty<FrozenActor>();
 		readonly Func<FrozenActor, bool> frozenActorIsValid = fa => fa.IsValid;
 		readonly Func<Actor, bool> actorIsInWorld = a => a.IsInWorld;
 		readonly Func<Actor, ActorBoundsPair> selectActorAndBounds;

OpenRA.Game/World.cs

@@ -51,7 +51,7 @@ namespace OpenRA
 		public LongBitSet<PlayerBitMask> AllPlayersMask = default(LongBitSet<PlayerBitMask>);
 		public readonly LongBitSet<PlayerBitMask> NoPlayersMask = default(LongBitSet<PlayerBitMask>);
 
-		public Player[] Players = new Player[0];
+		public Player[] Players = Array.Empty<Player>();
 
 		public event Action<Player> RenderPlayerChanged;