Fix RCS1077

.editorconfig

@@ -1023,6 +1023,9 @@ dotnet_diagnostic.RCS1072.severity = warning
 # Remove redundant constructor.
 dotnet_diagnostic.RCS1074.severity = warning
 
+# Optimize LINQ method call.
+dotnet_diagnostic.RCS1077.severity = warning
+
 # Use 'Count' property instead of 'Any' method.
 dotnet_diagnostic.RCS1080.severity = warning
 

OpenRA.Game/FileSystem/FileSystem.cs

@@ -328,7 +328,7 @@ namespace OpenRA.FileSystem
 				if (name == ".")
 					continue;
 
-				resolved = Directory.GetFileSystemEntries(resolved).FirstOrDefault(e => e.Equals(Path.Combine(resolved, name), StringComparison.InvariantCultureIgnoreCase));
+				resolved = Array.Find(Directory.GetFileSystemEntries(resolved), e => e.Equals(Path.Combine(resolved, name), StringComparison.InvariantCultureIgnoreCase));
 
 				if (resolved == null)
 					return null;

OpenRA.Game/GameRules/ActorInfo.cs

@@ -162,7 +162,7 @@ namespace OpenRA
 				throw new YamlException(exceptionString);
 			}
 
-			constructOrderCache = resolved.Select(r => r.Trait).ToList();
+			constructOrderCache = resolved.ConvertAll(r => r.Trait);
 			return constructOrderCache;
 		}
 

OpenRA.Game/MiniYaml.cs

@@ -670,7 +670,7 @@ namespace OpenRA
 		public MiniYamlBuilder(string value, List<MiniYamlNode> nodes)
 		{
 			Value = value;
-			Nodes = nodes == null ? new List<MiniYamlNodeBuilder>() : nodes.Select(x => new MiniYamlNodeBuilder(x)).ToList();
+			Nodes = nodes == null ? new List<MiniYamlNodeBuilder>() : nodes.ConvertAll(x => new MiniYamlNodeBuilder(x));
 		}
 
 		public MiniYaml Build()

OpenRA.Game/Network/UnitOrders.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Server;
@@ -42,7 +43,7 @@ namespace OpenRA.Network
 
 		static Player FindPlayerByClient(this World world, Session.Client c)
 		{
-			return world.Players.FirstOrDefault(p => p.ClientIndex == c.Index && p.PlayerReference.Playable);
+			return Array.Find(world.Players, p => p.ClientIndex == c.Index && p.PlayerReference.Playable);
 		}
 
 		static bool OrderNotFromServerOrWorldIsReplay(int clientId, World world) => clientId != 0 || (world != null && world.IsReplay);
@@ -184,12 +185,12 @@ namespace OpenRA.Network
 					if (!string.IsNullOrEmpty(order.TargetString))
 					{
 						var data = MiniYaml.FromString(order.TargetString);
-						var saveLastOrdersFrame = data.FirstOrDefault(n => n.Key == "SaveLastOrdersFrame");
+						var saveLastOrdersFrame = data.Find(n => n.Key == "SaveLastOrdersFrame");
 						if (saveLastOrdersFrame != null)
 							orderManager.GameSaveLastFrame =
 								FieldLoader.GetValue<int>("saveLastOrdersFrame", saveLastOrdersFrame.Value.Value);
 
-						var saveSyncFrame = data.FirstOrDefault(n => n.Key == "SaveSyncFrame");
+						var saveSyncFrame = data.Find(n => n.Key == "SaveSyncFrame");
 						if (saveSyncFrame != null)
 							orderManager.GameSaveLastSyncFrame =
 								FieldLoader.GetValue<int>("SaveSyncFrame", saveSyncFrame.Value.Value);
@@ -374,7 +375,7 @@ namespace OpenRA.Network
 						var strings = node.Key.Split('@');
 						if (strings[0] == "ConnectionQuality")
 						{
-							var client = orderManager.LobbyInfo.Clients.FirstOrDefault(c => c.Index == Exts.ParseInt32Invariant(strings[1]));
+							var client = orderManager.LobbyInfo.Clients.Find(c => c.Index == Exts.ParseInt32Invariant(strings[1]));
 							if (client != null)
 								client.ConnectionQuality = FieldLoader.GetValue<Session.ConnectionQuality>("ConnectionQuality", node.Value.Value);
 						}

OpenRA.Game/Player.cs

@@ -109,14 +109,14 @@ namespace OpenRA
 				.Where(f => !requireSelectable || f.Selectable)
 				.ToList();
 
-			var selected = selectableFactions.FirstOrDefault(f => f.InternalName == factionName)
+			var selected = selectableFactions.Find(f => f.InternalName == factionName)
 				?? selectableFactions.Random(playerRandom);
 
 			// Don't loop infinite
 			for (var i = 0; i <= 10 && selected.RandomFactionMembers.Count > 0; i++)
 			{
 				var faction = selected.RandomFactionMembers.Random(playerRandom);
-				selected = selectableFactions.FirstOrDefault(f => f.InternalName == faction);
+				selected = selectableFactions.Find(f => f.InternalName == faction);
 
 				if (selected == null)
 					throw new YamlException($"Unknown faction: {faction}");
@@ -179,7 +179,7 @@ namespace OpenRA
 			else
 			{
 				// Map player
-				ClientIndex = world.LobbyInfo.Clients.FirstOrDefault(c => c.IsAdmin)?.Index ?? 0; // Owned by the host (TODO: fix this)
+				ClientIndex = world.LobbyInfo.Clients.Find(c => c.IsAdmin)?.Index ?? 0; // Owned by the host (TODO: fix this)
 				Color = pr.Color;
 				PlayerName = pr.Name;
 				NonCombatant = pr.NonCombatant;

OpenRA.Game/Scripting/ScriptContext.cs

@@ -211,7 +211,7 @@ namespace OpenRA.Scripting
 			var bindings = Game.ModData.ObjectCreator.GetTypesImplementing<ScriptGlobal>();
 			foreach (var b in bindings)
 			{
-				var ctor = b.GetConstructors(BindingFlags.Public | BindingFlags.Instance).FirstOrDefault(c =>
+				var ctor = Array.Find(b.GetConstructors(BindingFlags.Public | BindingFlags.Instance), c =>
 				{
 					var p = c.GetParameters();
 					return p.Length == 1 && p.First().ParameterType == typeof(ScriptContext);

OpenRA.Game/Server/Server.cs

@@ -1160,7 +1160,7 @@ namespace OpenRA.Server
 		}
 
 		public bool HasClientWonOrLost(Session.Client client) =>
-			worldPlayers.FirstOrDefault(p => p?.ClientIndex == client.Index)?.Outcome != WinState.Undefined;
+			worldPlayers.Find(p => p?.ClientIndex == client.Index)?.Outcome != WinState.Undefined;
 
 		public void DropClient(Connection toDrop)
 		{
@@ -1169,7 +1169,7 @@ namespace OpenRA.Server
 				orderBuffer?.RemovePlayer(toDrop.PlayerIndex);
 				Conns.Remove(toDrop);
 
-				var dropClient = LobbyInfo.Clients.FirstOrDefault(c => c.Index == toDrop.PlayerIndex);
+				var dropClient = LobbyInfo.Clients.Find(c => c.Index == toDrop.PlayerIndex);
 				if (dropClient == null)
 				{
 					toDrop.Dispose();
@@ -1251,7 +1251,7 @@ namespace OpenRA.Server
 			lock (LobbyInfo)
 			{
 				// TODO: Only need to sync the specific client that has changed to avoid conflicts!
-				var clientData = LobbyInfo.Clients.Select(client => client.Serialize()).ToList();
+				var clientData = LobbyInfo.Clients.ConvertAll(client => client.Serialize());
 
 				DispatchServerOrdersToClients(Order.FromTargetString("SyncLobbyClients", clientData.WriteToString(), true));
 

OpenRA.Game/Settings.cs

@@ -348,7 +348,7 @@ namespace OpenRA
 							LoadSectionYaml(yamlSection.Value, settingsSection);
 					}
 
-					var keysNode = yamlCache.FirstOrDefault(n => n.Key == "Keys");
+					var keysNode = yamlCache.Find(n => n.Key == "Keys");
 					if (keysNode != null)
 						foreach (var node in keysNode.Value.Nodes)
 							if (node.Key != null)
@@ -370,10 +370,10 @@ namespace OpenRA
 
 		public void Save()
 		{
-			var yamlCacheBuilder = yamlCache.Select(n => new MiniYamlNodeBuilder(n)).ToList();
+			var yamlCacheBuilder = yamlCache.ConvertAll(n => new MiniYamlNodeBuilder(n));
 			foreach (var kv in Sections)
 			{
-				var sectionYaml = yamlCacheBuilder.FirstOrDefault(x => x.Key == kv.Key);
+				var sectionYaml = yamlCacheBuilder.Find(x => x.Key == kv.Key);
 				if (sectionYaml == null)
 				{
 					sectionYaml = new MiniYamlNodeBuilder(kv.Key, new MiniYamlBuilder(""));
@@ -403,7 +403,7 @@ namespace OpenRA
 				}
 			}
 
-			var keysYaml = yamlCacheBuilder.FirstOrDefault(x => x.Key == "Keys");
+			var keysYaml = yamlCacheBuilder.Find(x => x.Key == "Keys");
 			if (keysYaml == null)
 			{
 				keysYaml = new MiniYamlNodeBuilder("Keys", new MiniYamlBuilder(""));

OpenRA.Game/UtilityCommands/ExtractChromeStrings.cs

@@ -59,7 +59,7 @@ namespace OpenRA.UtilityCommands
 					modData.ModFiles.TryGetPackageContaining(chrome, out var chromePackage, out var chromeName);
 					var chromePath = Path.Combine(chromePackage.Name, chromeName);
 
-					var yaml = MiniYaml.FromFile(chromePath, false).Select(n => new MiniYamlNodeBuilder(n)).ToList();
+					var yaml = MiniYaml.FromFile(chromePath, false).ConvertAll(n => new MiniYamlNodeBuilder(n));
 					chromeFiles.Add((chromePath, yaml));
 
 					var translationCandidates = new List<TranslationCandidate>();

OpenRA.Mods.Cnc/Scripting/Properties/InfiltrateProperties.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Linq;
 using Eluant;
 using OpenRA.Mods.Cnc.Activities;
@@ -32,7 +33,7 @@ namespace OpenRA.Mods.Cnc.Scripting
 		[Desc("Infiltrate the target actor.")]
 		public void Infiltrate(Actor target)
 		{
-			var infiltrates = infiltratesTraits.FirstOrDefault(x => !x.IsTraitDisabled && x.Info.Types.Overlaps(target.GetEnabledTargetTypes()));
+			var infiltrates = Array.Find(infiltratesTraits, x => !x.IsTraitDisabled && x.Info.Types.Overlaps(target.GetEnabledTargetTypes()));
 
 			if (infiltrates == null)
 				throw new LuaException($"{Self} tried to infiltrate invalid target {target}!");

OpenRA.Mods.Cnc/Traits/SupportPowers/GrantPrerequisiteChargeDrainPower.cs

@@ -161,7 +161,7 @@ namespace OpenRA.Mods.Cnc.Traits
 				if (!available || order.ExtraData != 1)
 					return;
 
-				var power = Instances.FirstOrDefault(i => !i.IsTraitPaused);
+				var power = Instances.Find(i => !i.IsTraitPaused);
 				if (power == null)
 					return;
 

OpenRA.Mods.Cnc/UtilityCommands/ConvertPngToShpCommand.cs

@@ -35,7 +35,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 			var inputFiles = GlobArgs(args).OrderBy(a => a).ToList();
 			var dest = inputFiles[0].Split('-').First() + ".shp";
 
-			var frames = inputFiles.Select(a => new Png(File.OpenRead(a))).ToList();
+			var frames = inputFiles.ConvertAll(a => new Png(File.OpenRead(a)));
 			if (frames.Any(f => f.Type != SpriteFrameType.Indexed8))
 				throw new InvalidOperationException("All frames must be paletted");
 

OpenRA.Mods.Common/Activities/LayMines.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Activities;
@@ -175,7 +176,7 @@ namespace OpenRA.Mods.Common.Activities
 		{
 			if (ammoPools != null)
 			{
-				var pool = ammoPools.FirstOrDefault(x => x.Info.Name == minelayer.Info.AmmoPoolName);
+				var pool = Array.Find(ammoPools, x => x.Info.Name == minelayer.Info.AmmoPoolName);
 				if (pool == null)
 					return false;
 
@@ -193,7 +194,7 @@ namespace OpenRA.Mods.Common.Activities
 		{
 			if (ammoPools != null)
 			{
-				var pool = ammoPools.FirstOrDefault(x => x.Info.Name == minelayer.Info.AmmoPoolName);
+				var pool = Array.Find(ammoPools, x => x.Info.Name == minelayer.Info.AmmoPoolName);
 				if (pool == null)
 					return false;
 

OpenRA.Mods.Common/Activities/Resupply.cs

@@ -141,7 +141,7 @@ namespace OpenRA.Mods.Common.Activities
 					QueueChild(move.MoveWithinRange(host, closeEnough, targetLineColor: moveInfo.GetTargetLineColor()));
 
 				var delta = (self.CenterPosition - host.CenterPosition).LengthSquared;
-				transportCallers.FirstOrDefault(t => t.MinimumDistance.LengthSquared < delta)?.RequestTransport(self, targetCell);
+				Array.Find(transportCallers, t => t.MinimumDistance.LengthSquared < delta)?.RequestTransport(self, targetCell);
 
 				return false;
 			}
@@ -256,7 +256,7 @@ namespace OpenRA.Mods.Common.Activities
 
 		void RepairTick(Actor self)
 		{
-			var repairsUnits = allRepairsUnits.FirstOrDefault(r => !r.IsTraitDisabled && !r.IsTraitPaused);
+			var repairsUnits = Array.Find(allRepairsUnits, r => !r.IsTraitDisabled && !r.IsTraitPaused);
 			if (repairsUnits == null)
 			{
 				if (!allRepairsUnits.Any(r => r.IsTraitPaused))

OpenRA.Mods.Common/FileFormats/MSCabCompression.cs

@@ -89,7 +89,7 @@ namespace OpenRA.Mods.Common.FileFormats
 
 		public void ExtractFile(string filename, Stream output, Action<int> onProgress = null)
 		{
-			var file = files.FirstOrDefault(f => f.FileName == filename);
+			var file = Array.Find(files, f => f.FileName == filename);
 			if (file == null)
 				throw new FileNotFoundException(filename);
 

OpenRA.Mods.Common/HitShapes/Rectangle.cs

@@ -69,7 +69,7 @@ namespace OpenRA.Mods.Common.HitShapes
 			var topRight = new int2(BottomRight.X, TopLeft.Y);
 			var bottomLeft = new int2(TopLeft.X, BottomRight.Y);
 			var corners = new[] { TopLeft, BottomRight, topRight, bottomLeft };
-			OuterRadius = new WDist(corners.Select(x => x.Length).Max());
+			OuterRadius = new WDist(corners.Max(x => x.Length));
 
 			combatOverlayVertsTop = new WVec[]
 			{

OpenRA.Mods.Common/Scripting/Global/PlayerGlobal.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Linq;
 using Eluant;
 using OpenRA.Scripting;
@@ -24,7 +25,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Returns the player with the specified internal name, or nil if a match is not found.")]
 		public Player GetPlayer(string name)
 		{
-			return Context.World.Players.FirstOrDefault(p => p.InternalName == name);
+			return Array.Find(Context.World.Players, p => p.InternalName == name);
 		}
 
 		[Desc("Returns a table of players filtered by the specified function.")]

OpenRA.Mods.Common/Scripting/Properties/AmmoPoolProperties.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Linq;
 using Eluant;
 using OpenRA.Mods.Common.Traits;
@@ -33,7 +34,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Returns the count of the actor's specified ammopool.")]
 		public int AmmoCount(string poolName = "primary")
 		{
-			var pool = ammoPools.FirstOrDefault(a => a.Info.Name == poolName);
+			var pool = Array.Find(ammoPools, a => a.Info.Name == poolName);
 			if (pool == null)
 				throw new LuaException($"Invalid ammopool name {poolName} queried on actor {self}.");
 
@@ -43,7 +44,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Returns the maximum count of ammo the actor can load.")]
 		public int MaximumAmmoCount(string poolName = "primary")
 		{
-			var pool = ammoPools.FirstOrDefault(a => a.Info.Name == poolName);
+			var pool = Array.Find(ammoPools, a => a.Info.Name == poolName);
 			if (pool == null)
 				throw new LuaException($"Invalid ammopool name {poolName} queried on actor {self}.");
 
@@ -54,7 +55,7 @@ namespace OpenRA.Mods.Common.Scripting
 			"(Use a negative amount to remove ammo.)")]
 		public void Reload(string poolName = "primary", int amount = 1)
 		{
-			var pool = ammoPools.FirstOrDefault(a => a.Info.Name == poolName);
+			var pool = Array.Find(ammoPools, a => a.Info.Name == poolName);
 			if (pool == null)
 				throw new LuaException($"Invalid ammopool name {poolName} queried on actor {self}.");
 

OpenRA.Mods.Common/Scripting/Properties/ConditionProperties.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Linq;
 using Eluant;
 using OpenRA.Mods.Common.Traits;
@@ -33,8 +34,7 @@ namespace OpenRA.Mods.Common.Scripting
 			"If duration > 0 the condition will be automatically revoked after the defined number of ticks.")]
 		public int GrantCondition(string condition, int duration = 0)
 		{
-			var external = externalConditions
+			var external = Array.Find(externalConditions, t => t.Info.Condition == condition && t.CanGrantCondition(this));
-				.FirstOrDefault(t => t.Info.Condition == condition && t.CanGrantCondition(this));
 
 			if (external == null)
 				throw new LuaException($"Condition `{condition}` has not been listed on an enabled ExternalCondition trait");

OpenRA.Mods.Common/Scripting/Properties/PlayerConditionProperties.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Linq;
 using Eluant;
 using OpenRA.Mods.Common.Traits;
@@ -32,8 +33,7 @@ namespace OpenRA.Mods.Common.Scripting
 			"If duration > 0 the condition will be automatically revoked after the defined number of ticks.")]
 		public int GrantCondition(string condition, int duration = 0)
 		{
-			var external = externalConditions
+			var external = Array.Find(externalConditions, t => t.Info.Condition == condition && t.CanGrantCondition(this));
-				.FirstOrDefault(t => t.Info.Condition == condition && t.CanGrantCondition(this));
 
 			if (external == null)
 				throw new LuaException($"Condition `{condition}` has not been listed on an enabled ExternalCondition trait");

OpenRA.Mods.Common/Scripting/Properties/PlayerProperties.cs

@@ -47,7 +47,7 @@ namespace OpenRA.Mods.Common.Scripting
 		{
 			get
 			{
-				var c = Player.World.LobbyInfo.Clients.FirstOrDefault(i => i.Index == Player.ClientIndex);
+				var c = Player.World.LobbyInfo.Clients.Find(i => i.Index == Player.ClientIndex);
 				return c?.Team ?? 0;
 			}
 		}
@@ -57,7 +57,7 @@ namespace OpenRA.Mods.Common.Scripting
 		{
 			get
 			{
-				var c = Player.World.LobbyInfo.Clients.FirstOrDefault(i => i.Index == Player.ClientIndex);
+				var c = Player.World.LobbyInfo.Clients.Find(i => i.Index == Player.ClientIndex);
 				return c?.Handicap ?? 0;
 			}
 		}

OpenRA.Mods.Common/Scripting/Properties/ProductionProperties.cs

@@ -187,8 +187,7 @@ namespace OpenRA.Mods.Common.Scripting
 			if (triggers.HasAnyCallbacksFor(Trigger.OnProduction))
 				return true;
 
-			return queues.Where(q => GetBuildableInfo(actorType).Queue.Contains(q.Info.Type))
+			return queues.Any(q => GetBuildableInfo(actorType).Queue.Contains(q.Info.Type) && q.AllQueued().Any());
-				.Any(q => q.AllQueued().Any());
 		}
 
 		BuildableInfo GetBuildableInfo(string actorType)

OpenRA.Mods.Common/ServerTraits/LobbyCommands.cs

@@ -278,7 +278,7 @@ namespace OpenRA.Mods.Common.Server
 				{
 					// Client 0 will always be the Host
 					// In some cases client 0 doesn't exist, so we untick all players
-					var host = server.LobbyInfo.Clients.FirstOrDefault(c => c.Index == 0);
+					var host = server.LobbyInfo.Clients.Find(c => c.Index == 0);
 					if (host != null)
 						host.State = Session.ClientState.NotReady;
 					else
@@ -442,7 +442,7 @@ namespace OpenRA.Mods.Common.Server
 					}
 					else
 					{
-						var occupantConn = server.Conns.FirstOrDefault(c => c.PlayerIndex == occupant.Index);
+						var occupantConn = server.Conns.Find(c => c.PlayerIndex == occupant.Index);
 						if (occupantConn != null)
 						{
 							server.SendOrderTo(conn, "ServerError", SlotClosed);
@@ -1143,7 +1143,7 @@ namespace OpenRA.Mods.Common.Server
 			if (spawnPoint == 0)
 				return true;
 
-			var existingClient = server.LobbyInfo.Clients.FirstOrDefault(cc => cc.SpawnPoint == spawnPoint);
+			var existingClient = server.LobbyInfo.Clients.Find(cc => cc.SpawnPoint == spawnPoint);
 			if (client != existingClient && !client.IsAdmin)
 			{
 				server.SendLocalizedMessageTo(conn, AdminClearSpawn);
@@ -1200,7 +1200,7 @@ namespace OpenRA.Mods.Common.Server
 					return true;
 				}
 
-				if (server.LobbyInfo.Clients.Where(cc => cc != client).Any(cc => (cc.SpawnPoint == spawnPoint) && (cc.SpawnPoint != 0)))
+				if (server.LobbyInfo.Clients.Any(cc => cc != client && (cc.SpawnPoint == spawnPoint) && (cc.SpawnPoint != 0)))
 				{
 					server.SendLocalizedMessageTo(conn, SpawnOccupied);
 					return true;

OpenRA.Mods.Common/ServerTraits/SkirmishLogic.cs

@@ -165,7 +165,7 @@ namespace OpenRA.Mods.Common.Server
 
 			var slot = server.LobbyInfo.FirstEmptyBotSlot();
 			var bot = server.Map.PlayerActorInfo.TraitInfos<IBotInfo>().Select(t => t.Type).FirstOrDefault();
-			var botController = server.LobbyInfo.Clients.FirstOrDefault(c => c.IsAdmin);
+			var botController = server.LobbyInfo.Clients.Find(c => c.IsAdmin);
 			if (slot != null && bot != null)
 				server.InterpretCommand($"slot_bot {slot} {botController.Index} {bot}", conn);
 		}

OpenRA.Mods.Common/Traits/AttackMove.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.Common.Activities;
@@ -162,7 +163,7 @@ namespace OpenRA.Mods.Common.Traits
 				if (world.Map.Contains(cell))
 				{
 					var explored = subject.Actor.Owner.Shroud.IsExplored(cell);
-					var cannotMove = subjects.FirstOrDefault(a => !a.Trait.Info.MoveIntoShroud).Trait;
+					var cannotMove = Array.Find(subjects, a => !a.Trait.Info.MoveIntoShroud).Trait;
 					var blocked = !explored && cannotMove != null;
 
 					if (isAssaultMove)

OpenRA.Mods.Common/Traits/BotModules/SquadManagerBotModule.cs

@@ -305,7 +305,7 @@ namespace OpenRA.Mods.Common.Traits
 		// HACK: Use of this function requires that there is one squad of this type.
 		Squad GetSquadOfType(SquadType type)
 		{
-			return Squads.FirstOrDefault(s => s.Type == type);
+			return Squads.Find(s => s.Type == type);
 		}
 
 		Squad RegisterNewSquad(IBot bot, SquadType type, (Actor Actor, WVec Offset) target = default)
@@ -446,7 +446,7 @@ namespace OpenRA.Mods.Common.Traits
 					ownUnits.First())
 					.ToList();
 
-				if (AttackOrFleeFuzzy.Rush.CanAttack(ownUnits, enemies.Select(x => x.Actor).ToList()))
+				if (AttackOrFleeFuzzy.Rush.CanAttack(ownUnits, enemies.ConvertAll(x => x.Actor)))
 				{
 					var target = enemies.Count > 0 ? enemies.Random(World.LocalRandom) : enemyBaseBuilder;
 					var rush = GetSquadOfType(SquadType.Rush);
@@ -508,7 +508,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			return new List<MiniYamlNode>()
 			{
-				new("Squads", "", Squads.Select(s => new MiniYamlNode("Squad", s.Serialize())).ToList()),
+				new("Squads", "", Squads.ConvertAll(s => new MiniYamlNode("Squad", s.Serialize()))),
 				new("InitialBaseCenter", FieldSaver.FormatValue(initialBaseCenter)),
 				new("UnitsHangingAroundTheBase", FieldSaver.FormatValue(unitsHangingAroundTheBase
 					.Where(a => !unitCannotBeOrdered(a))

OpenRA.Mods.Common/Traits/Buildings/Exit.cs

@@ -57,7 +57,9 @@ namespace OpenRA.Mods.Common.Traits
 				.ThenBy(e => (actor.World.Map.CenterOfCell(actor.Location + e.Info.ExitCell) - pos).LengthSquared)
 				.ToList();
 
+#pragma warning disable RCS1077 // Optimize LINQ method call.
 			return p != null ? all.FirstOrDefault(p) : all.FirstOrDefault();
+#pragma warning restore RCS1077 // Optimize LINQ method call.
 		}
 
 		public static IEnumerable<Exit> Exits(this Actor actor, string productionType = null)

OpenRA.Mods.Common/Traits/Buildings/TransformsIntoAircraft.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.Common.Activities;
@@ -142,7 +143,7 @@ namespace OpenRA.Mods.Common.Traits
 				return;
 
 			var currentTransform = self.CurrentActivity as Transform;
-			var transform = transforms.FirstOrDefault(t => !t.IsTraitDisabled && !t.IsTraitPaused);
+			var transform = Array.Find(transforms, t => !t.IsTraitDisabled && !t.IsTraitPaused);
 			if (transform == null && currentTransform == null)
 				return;
 

OpenRA.Mods.Common/Traits/Buildings/TransformsIntoEntersTunnels.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.Common.Activities;
@@ -94,7 +95,7 @@ namespace OpenRA.Mods.Common.Traits
 				return;
 
 			var currentTransform = self.CurrentActivity as Transform;
-			var transform = transforms.FirstOrDefault(t => !t.IsTraitDisabled && !t.IsTraitPaused);
+			var transform = Array.Find(transforms, t => !t.IsTraitDisabled && !t.IsTraitPaused);
 			if (transform == null && currentTransform == null)
 				return;
 

OpenRA.Mods.Common/Traits/Buildings/TransformsIntoMobile.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.Common.Activities;
@@ -120,7 +121,7 @@ namespace OpenRA.Mods.Common.Traits
 					return;
 
 				var currentTransform = self.CurrentActivity as Transform;
-				var transform = transforms.FirstOrDefault(t => !t.IsTraitDisabled && !t.IsTraitPaused);
+				var transform = Array.Find(transforms, t => !t.IsTraitDisabled && !t.IsTraitPaused);
 				if (transform == null && currentTransform == null)
 					return;
 

OpenRA.Mods.Common/Traits/Buildings/TransformsIntoPassenger.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.Common.Activities;
@@ -128,7 +129,7 @@ namespace OpenRA.Mods.Common.Traits
 				return;
 
 			var currentTransform = self.CurrentActivity as Transform;
-			var transform = transforms.FirstOrDefault(t => !t.IsTraitDisabled && !t.IsTraitPaused);
+			var transform = Array.Find(transforms, t => !t.IsTraitDisabled && !t.IsTraitPaused);
 			if (transform == null && currentTransform == null)
 				return;
 

OpenRA.Mods.Common/Traits/Buildings/TransformsIntoRepairable.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.Common.Activities;
@@ -122,7 +123,7 @@ namespace OpenRA.Mods.Common.Traits
 				return;
 
 			var currentTransform = self.CurrentActivity as Transform;
-			var transform = transforms.FirstOrDefault(t => !t.IsTraitDisabled && !t.IsTraitPaused);
+			var transform = Array.Find(transforms, t => !t.IsTraitDisabled && !t.IsTraitPaused);
 			if (transform == null && currentTransform == null)
 				return;
 

OpenRA.Mods.Common/Traits/Crates/GrantExternalConditionCrateAction.cs

@@ -84,7 +84,7 @@ namespace OpenRA.Mods.Common.Traits
 			{
 				if (external == null || !external.CanGrantCondition(self))
 				{
-					external = externals.FirstOrDefault(t => t.CanGrantCondition(self));
+					external = externals.Find(t => t.CanGrantCondition(self));
 					if (external == null)
 						break;
 				}

OpenRA.Mods.Common/Traits/Minelayer.cs

@@ -310,7 +310,7 @@ namespace OpenRA.Mods.Common.Traits
 			protected override IEnumerable<IRenderable> Render(WorldRenderer wr, World world) { yield break; }
 			protected override IEnumerable<IRenderable> RenderAboveShroud(WorldRenderer wr, World world)
 			{
-				var minelayer = minelayers.FirstOrDefault(m => m.IsInWorld && !m.IsDead);
+				var minelayer = minelayers.Find(m => m.IsInWorld && !m.IsDead);
 				if (minelayer == null)
 					yield break;
 

OpenRA.Mods.Common/Traits/Player/ClassicParallelProductionQueue.cs

@@ -84,7 +84,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (allProductionPaused)
 				return;
 
-			var item = Queue.FirstOrDefault(i => !i.Paused);
+			var item = Queue.Find(i => !i.Paused);
 			if (item == null)
 				return;
 

OpenRA.Mods.Common/Traits/Player/GameSaveViewportManager.cs

@@ -9,8 +9,8 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
-using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Traits;
 
@@ -34,7 +34,7 @@ namespace OpenRA.Mods.Common.Traits
 			// TODO: This won't make sense for MP saves
 			var localPlayer = worldRenderer.World.LocalPlayer;
 			if ((localPlayer != null && localPlayer.PlayerActor != self) ||
-				(localPlayer == null && self.Owner != self.World.Players.FirstOrDefault(p => p.IsBot)))
+				(localPlayer == null && self.Owner != Array.Find(self.World.Players, p => p.IsBot)))
 				return null;
 
 			var nodes = new List<MiniYamlNode>()

OpenRA.Mods.Common/Traits/Player/ParallelProductionQueue.cs

@@ -27,7 +27,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			CancelUnbuildableItems();
 
-			var item = Queue.FirstOrDefault(i => !i.Paused);
+			var item = Queue.Find(i => !i.Paused);
 			if (item == null)
 				return;
 

OpenRA.Mods.Common/Traits/Player/PlaceBuilding.cs

@@ -175,7 +175,7 @@ namespace OpenRA.Mods.Common.Traits
 							.Where(p => p.AcceptsPlug(plugInfo.Type))
 							.ToList();
 
-						var pluggable = pluggables.FirstOrDefault(p => a.Location + p.Info.Offset == targetLocation)
+						var pluggable = pluggables.Find(p => a.Location + p.Info.Offset == targetLocation)
 							?? pluggables.FirstOrDefault();
 
 						if (pluggable == null)

OpenRA.Mods.Common/Traits/Player/ProductionQueue.cs

@@ -515,7 +515,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		protected virtual void PauseProduction(string itemName, bool paused)
 		{
-			Queue.FirstOrDefault(a => a.Item == itemName)?.Pause(paused);
+			Queue.Find(a => a.Item == itemName)?.Pause(paused);
 		}
 
 		protected virtual void CancelProduction(string itemName, uint numberToCancel)

OpenRA.Mods.Common/Traits/SupportPowers/SelectDirectionalTarget.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Widgets;
 using OpenRA.Orders;
@@ -152,7 +151,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		Arrow GetArrow(double degree)
 		{
-			var arrow = directionArrows.FirstOrDefault(d => d.EndAngle >= degree);
+			var arrow = Array.Find(directionArrows, d => d.EndAngle >= degree);
 			return arrow ?? directionArrows[0];
 		}
 

OpenRA.Mods.Common/Traits/SupportPowers/SupportPowerManager.cs

@@ -222,7 +222,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (!Ready)
 				return;
 
-			var power = Instances.FirstOrDefault(i => !i.IsTraitPaused);
+			var power = Instances.Find(i => !i.IsTraitPaused);
 
 			if (power == null)
 				return;

OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs

@@ -332,7 +332,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		public EditorActorPreview this[string id]
 		{
-			get { return previews.FirstOrDefault(p => p.ID.Equals(id, StringComparison.OrdinalIgnoreCase)); }
+			get { return previews.Find(p => p.ID.Equals(id, StringComparison.OrdinalIgnoreCase)); }
 		}
 	}
 }

OpenRA.Mods.Common/UpdateRules/Rules/20230225/ExplicitSequenceFilenames.cs

@@ -37,7 +37,7 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 		{
 			// Keep a resolved copy of the sequences so we can account for values imported through inheritance or Defaults.
 			// This will be modified during processing, so take a deep copy to avoid side-effects on other update rules.
-			this.resolvedImagesNodes = MiniYaml.FromString(resolvedImagesNodes.WriteToString()).Select(n => new MiniYamlNodeBuilder(n)).ToList();
+			this.resolvedImagesNodes = MiniYaml.FromString(resolvedImagesNodes.WriteToString()).ConvertAll(n => new MiniYamlNodeBuilder(n));
 
 			var requiredMetadata = new HashSet<string>();
 			foreach (var imageNode in resolvedImagesNodes)
@@ -213,7 +213,7 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 					{
 						resolvedDefaultsNode.Value.Nodes.Select(n => n.Build()).ToArray(),
 						resolvedSequenceNode.Value.Nodes.Select(n => n.Build()).ToArray()
-					}).Select(n => new MiniYamlNodeBuilder(n)).ToList();
+					}).ConvertAll(n => new MiniYamlNodeBuilder(n));
 					resolvedSequenceNode.Value.Value ??= resolvedDefaultsNode.Value.Value;
 				}
 			}

OpenRA.Mods.Common/UpdateRules/Rules/20231010/AbstractDocking.cs

@@ -45,7 +45,7 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 					harvesters[actorNode.Key] = harvesterNode.ChildrenMatching("DeliveryBuildings", includeRemovals: false)
 						.FirstOrDefault()?.NodeValue<HashSet<string>>() ?? new HashSet<string>();
 
-				if (actorNode.ChildrenMatching("Refinery", includeRemovals: false).FirstOrDefault() != null)
+				if (actorNode.ChildrenMatching("Refinery", includeRemovals: false).Any())
 					refineries.Add(actorNode.Key.ToLowerInvariant());
 			}
 
@@ -102,7 +102,7 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 					refineryNode.RemoveNode(dockOffsetNode);
 				}
 
-				var buildingNode = actorNode.Value.Nodes.FirstOrDefault(n => buildings.Any(b => n.KeyMatches(b, includeRemovals: false)));
+				var buildingNode = actorNode.Value.Nodes.Find(n => buildings.Any(b => n.KeyMatches(b, includeRemovals: false)));
 				if (buildingNode != null)
 				{
 					var dimensions = buildingNode.ChildrenMatching("Dimensions", includeRemovals: false).FirstOrDefault()?.NodeValue<CVec>() ?? new CVec(1, 1);

OpenRA.Mods.Common/UpdateRules/UpdatePath.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Mods.Common.UpdateRules.Rules;
@@ -98,7 +99,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 			if (namedType != null && namedType.IsSubclassOf(typeof(UpdateRule)))
 				return new[] { (UpdateRule)objectCreator.CreateBasic(namedType) };
 
-			return Paths.FirstOrDefault(p => p.source == source)?.Rules(chain);
+			return Array.Find(Paths, p => p.source == source)?.Rules(chain);
 		}
 
 		public static IEnumerable<string> KnownPaths { get { return Paths.Select(p => p.source); } }

OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs

@@ -35,7 +35,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 					continue;
 				}
 
-				yaml.Add(((IReadWritePackage)package, name, MiniYaml.FromStream(package.GetStream(name), name, false).Select(n => new MiniYamlNodeBuilder(n)).ToList()));
+				yaml.Add(((IReadWritePackage)package, name, MiniYaml.FromStream(package.GetStream(name), name, false).ConvertAll(n => new MiniYamlNodeBuilder(n))));
 			}
 
 			return yaml;
@@ -68,7 +68,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 			{
 				// Ignore any files that aren't in the map bundle
 				if (!filename.Contains('|') && mapPackage.Contains(filename))
-					fileSet.Add((mapPackage, filename, MiniYaml.FromStream(mapPackage.GetStream(filename), filename, false).Select(n => new MiniYamlNodeBuilder(n)).ToList()));
+					fileSet.Add((mapPackage, filename, MiniYaml.FromStream(mapPackage.GetStream(filename), filename, false).ConvertAll(n => new MiniYamlNodeBuilder(n))));
 				else if (modData.ModFiles.Exists(filename))
 					externalFilenames.Add(filename);
 			}
@@ -177,9 +177,9 @@ namespace OpenRA.Mods.Common.UpdateRules
 			}
 
 			if (mapNode != null && mapNode.Nodes.Count > 0)
-				yaml.Add(mapNode.Nodes.Select(n => n.Build()).ToList());
+				yaml.Add(mapNode.Nodes.ConvertAll(n => n.Build()));
 
-			return MiniYaml.Merge(yaml).Select(n => new MiniYamlNodeBuilder(n)).ToList();
+			return MiniYaml.Merge(yaml).ConvertAll(n => new MiniYamlNodeBuilder(n));
 		}
 
 		static IEnumerable<string> FilterExternalModFiles(ModData modData, IEnumerable<string> files, HashSet<string> externalFilenames)
@@ -241,7 +241,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 			if (rule is IBeforeUpdateActors beforeActors)
 			{
 				var resolvedActors = MiniYaml.Load(modData.DefaultFileSystem, modData.Manifest.Rules, null)
-					.Select(n => new MiniYamlNodeBuilder(n)).ToList();
+					.ConvertAll(n => new MiniYamlNodeBuilder(n));
 				manualSteps.AddRange(beforeActors.BeforeUpdateActors(modData, resolvedActors));
 			}
 
@@ -250,7 +250,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 			if (rule is IBeforeUpdateWeapons beforeWeapons)
 			{
 				var resolvedWeapons = MiniYaml.Load(modData.DefaultFileSystem, modData.Manifest.Weapons, null)
-					.Select(n => new MiniYamlNodeBuilder(n)).ToList();
+					.ConvertAll(n => new MiniYamlNodeBuilder(n));
 				manualSteps.AddRange(beforeWeapons.BeforeUpdateWeapons(modData, resolvedWeapons));
 			}
 
@@ -259,7 +259,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 			if (rule is IBeforeUpdateSequences beforeSequences)
 			{
 				var resolvedImages = MiniYaml.Load(modData.DefaultFileSystem, modData.Manifest.Sequences, null)
-					.Select(n => new MiniYamlNodeBuilder(n)).ToList();
+					.ConvertAll(n => new MiniYamlNodeBuilder(n));
 				manualSteps.AddRange(beforeSequences.BeforeUpdateSequences(modData, resolvedImages));
 			}
 

OpenRA.Mods.Common/UtilityCommands/Utilities.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.IO;
-using System.Linq;
 using OpenRA.FileSystem;
 
 namespace OpenRA.Mods.Common.UtilityCommands
@@ -47,7 +46,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 
 			var fs = map ?? modData.DefaultFileSystem;
 			var topLevelNodes = MiniYaml.Load(fs, manifestNodes, mapProperty);
-			return topLevelNodes.FirstOrDefault(n => n.Key == key);
+			return topLevelNodes.Find(n => n.Key == key);
 		}
 	}
 }

OpenRA.Mods.Common/Warheads/SpreadDamageWarhead.cs

@@ -91,7 +91,7 @@ namespace OpenRA.Mods.Common.Warheads
 						falloffDistance = closestDistance;
 						break;
 					case DamageCalculationType.ClosestTargetablePosition:
-						falloffDistance = victim.GetTargetablePositions().Select(x => (x - pos).Length).Min();
+						falloffDistance = victim.GetTargetablePositions().Min(x => (x - pos).Length);
 						break;
 					case DamageCalculationType.CenterPosition:
 						falloffDistance = (victim.CenterPosition - pos).Length;

OpenRA.Mods.Common/Widgets/Logic/Editor/SaveMapLogic.cs

@@ -146,8 +146,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 				if (map.Package != null)
 				{
-					selectedDirectory = writableDirectories.FirstOrDefault(k => k.Folder.Contains(map.Package.Name));
+					selectedDirectory = writableDirectories.Find(k => k.Folder.Contains(map.Package.Name));
-					selectedDirectory ??= writableDirectories.FirstOrDefault(k => Directory.GetDirectories(k.Folder.Name).Any(f => f.Contains(map.Package.Name)));
+					selectedDirectory ??= writableDirectories.Find(k => Directory.GetDirectories(k.Folder.Name).Any(f => f.Contains(map.Package.Name)));
 				}
 
 				// Prioritize MapClassification.User directories over system directories

OpenRA.Mods.Common/Widgets/Logic/Ingame/ClassicProductionLogic.cs

@@ -33,7 +33,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 			void SelectTab(bool reverse)
 			{
-				palette.CurrentQueue = queues.FirstOrDefault(q => q.Enabled);
+				palette.CurrentQueue = Array.Find(queues, q => q.Enabled);
 
 				// When a tab is selected, scroll to the top because the current row position may be invalid for the new tab
 				palette.ScrollToTop();

OpenRA.Mods.Common/Widgets/Logic/Ingame/GameInfoStatsLogic.cs

@@ -212,7 +212,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			}
 
 			var localClient = orderManager.LocalClient;
-			var localPlayer = localClient == null ? null : world.Players.FirstOrDefault(player => player.ClientIndex == localClient.Index);
+			var localPlayer = localClient == null ? null : Array.Find(world.Players, player => player.ClientIndex == localClient.Index);
 			bool LocalPlayerCanKick() => localClient != null
 				&& (Game.IsHost || ((!orderManager.LocalClient.IsObserver) && localPlayer.WinState == WinState.Undefined));
 			bool CanClientBeKicked(Session.Client client, Func<bool> isVoteKick) =>

OpenRA.Mods.Common/Widgets/Logic/Installation/ModContentPromptLogic.cs

@@ -80,7 +80,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				var downloadYaml = MiniYaml.Load(modFileSystem, content.Downloads, null);
 				modFileSystem.UnmountAll();
 
-				var download = downloadYaml.FirstOrDefault(n => n.Key == content.QuickDownload);
+				var download = downloadYaml.Find(n => n.Key == content.QuickDownload);
 				if (download == null)
 					throw new InvalidOperationException($"Mod QuickDownload `{content.QuickDownload}` definition not found.");
 

OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs

@@ -274,7 +274,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 					var botTypes = map.PlayerActorInfo.TraitInfos<IBotInfo>().Select(t => t.Type);
 					var options = new Dictionary<string, IEnumerable<DropDownOption>>();
 
-					var botController = orderManager.LobbyInfo.Clients.FirstOrDefault(c => c.IsAdmin);
+					var botController = orderManager.LobbyInfo.Clients.Find(c => c.IsAdmin);
 					if (orderManager.LobbyInfo.Slots.Values.Any(s => s.AllowBots))
 					{
 						var botOptions = new List<DropDownOption>()

OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs

@@ -74,7 +74,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			{
 				foreach (var b in map.PlayerActorInfo.TraitInfos<IBotInfo>())
 				{
-					var botController = orderManager.LobbyInfo.Clients.FirstOrDefault(c => c.IsAdmin);
+					var botController = orderManager.LobbyInfo.Clients.Find(c => c.IsAdmin);
 					bots.Add(new SlotDropDownOption(b.Name,
 						$"slot_bot {slot.PlayerReference} {botController.Index} {b.Type}",
 						() => client != null && client.Bot == b.Type));
@@ -266,7 +266,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		static void ClearPlayerSpawnPoint(OrderManager orderManager, MapPreviewWidget mapPreview, MapPreview preview, MouseInput mi)
 		{
 			var selectedSpawn = DetermineSelectedSpawnPoint(mapPreview, preview, mi);
-			if (Game.IsHost || orderManager.LobbyInfo.Clients.FirstOrDefault(cc => cc.SpawnPoint == selectedSpawn) == orderManager.LocalClient)
+			if (Game.IsHost || orderManager.LobbyInfo.Clients.Find(cc => cc.SpawnPoint == selectedSpawn) == orderManager.LocalClient)
 				orderManager.IssueOrder(Order.Command($"clear_spawn {selectedSpawn}"));
 		}
 

OpenRA.Mods.Common/Widgets/Logic/MapChooserLogic.cs

@@ -356,7 +356,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 				gameModeDropdown.GetText = () =>
 				{
-					var item = categories.FirstOrDefault(m => m.Category == category);
+					var item = categories.Find(m => m.Category == category);
 					if (item == default((string, int)))
 						item.Category = TranslationProvider.GetString(NoMatches);
 

OpenRA.Mods.Common/Widgets/Logic/ReplayBrowserLogic.cs

@@ -696,7 +696,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 		void SelectFirstVisibleReplay()
 		{
-			SelectReplay(replays.FirstOrDefault(r => replayState[r].Visible));
+			SelectReplay(replays.Find(r => replayState[r].Visible));
 		}
 
 		void SelectReplay(ReplayMetadata replay)

OpenRA.Mods.Common/Widgets/Logic/Settings/AudioSettingsLogic.cs

@@ -103,7 +103,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			videoVolumeSlider.OnChange += x => Game.Sound.VideoVolume = x;
 
 			var devices = Game.Sound.AvailableDevices();
-			soundDevice = devices.FirstOrDefault(d => d.Device == ss.Device) ?? devices.First();
+			soundDevice = Array.Find(devices, d => d.Device == ss.Device) ?? devices.First();
 
 			var audioDeviceDropdown = panel.Get<DropDownButtonWidget>("AUDIO_DEVICE");
 			audioDeviceDropdown.OnMouseDown = _ => ShowAudioDeviceDropdown(audioDeviceDropdown, devices, scrollPanel);

OpenRA.Mods.Common/Widgets/ResourcePreviewWidget.cs

@@ -38,7 +38,7 @@ namespace OpenRA.Mods.Common.Widgets
 			{
 				resourceType = value;
 				if (resourceType != null)
-					resourceRenderer = resourceRenderers.FirstOrDefault(r => r.ResourceTypes.Contains(resourceType));
+					resourceRenderer = Array.Find(resourceRenderers, r => r.ResourceTypes.Contains(resourceType));
 				else
 					resourceRenderer = null;
 			}

OpenRA.Mods.Common/Widgets/ScrollPanelWidget.cs

@@ -10,7 +10,6 @@
 #endregion
 
 using System;
-using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Primitives;
 using OpenRA.Widgets;
@@ -284,7 +283,7 @@ namespace OpenRA.Mods.Common.Widgets
 
 		public void ScrollToItem(string itemKey, bool smooth = false)
 		{
-			var item = Children.FirstOrDefault(c => c is ScrollItemWidget si && si.ItemKey == itemKey);
+			var item = Children.Find(c => c is ScrollItemWidget si && si.ItemKey == itemKey);
 
 			if (item != null)
 				ScrollToItem(item, smooth);
@@ -292,7 +291,7 @@ namespace OpenRA.Mods.Common.Widgets
 
 		public void ScrollToSelectedItem()
 		{
-			var item = Children.FirstOrDefault(c => c is ScrollItemWidget si && si.IsSelected());
+			var item = Children.Find(c => c is ScrollItemWidget si && si.IsSelected());
 
 			if (item != null)
 				ScrollToItem(item);
@@ -469,7 +468,7 @@ namespace OpenRA.Mods.Common.Widgets
 				if (collection != col)
 					return;
 
-				var widget = Children.FirstOrDefault(w => widgetItemEquals(w, item));
+				var widget = Children.Find(w => widgetItemEquals(w, item));
 				if (widget != null)
 					RemoveChild(widget);
 			});