diff --git a/.editorconfig b/.editorconfig
index ae322722d9..b50db22e9b 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -147,6 +147,9 @@ dotnet_diagnostic.IDE0044.severity = warning
 # Unused private member.
 dotnet_diagnostic.IDE0052.severity = warning
 
+# Unnecessary value assignment.
+dotnet_diagnostic.IDE0059.severity = warning
+
 # Unused parameter.
 dotnet_diagnostic.IDE0060.severity = warning
 
diff --git a/OpenRA.Game/WDist.cs b/OpenRA.Game/WDist.cs
index 7388f1dd34..a46940e2b0 100644
--- a/OpenRA.Game/WDist.cs
+++ b/OpenRA.Game/WDist.cs
@@ -66,7 +66,7 @@ namespace OpenRA
 			s = s.ToLowerInvariant();
 			var components = s.Split('c');
 			var cell = 0;
-			var subcell = 0;
+			int subcell;
 
 			switch (components.Length)
 			{
diff --git a/OpenRA.Mods.Cnc/FileFormats/BlowfishKeyProvider.cs b/OpenRA.Mods.Cnc/FileFormats/BlowfishKeyProvider.cs
index ff43999991..75eaa2952c 100644
--- a/OpenRA.Mods.Cnc/FileFormats/BlowfishKeyProvider.cs
+++ b/OpenRA.Mods.Cnc/FileFormats/BlowfishKeyProvider.cs
@@ -224,13 +224,11 @@ namespace OpenRA.Mods.Cnc.FileFormats
 			uint nTwoByteLen, bit;
 			int nTwoBitLen;
 
-			var j = 0;
-
 			InitBigNum(nTmp, 0, len);
 			InitBigNum(n1, 0, len);
 			nTwoBitLen = (int)BitLenBigNum(n2, len);
 			bit = 1U << (nTwoBitLen % 32);
-			j = ((nTwoBitLen + 32) / 32) - 1;
+			var j = ((nTwoBitLen + 32) / 32) - 1;
 			nTwoByteLen = (uint)((nTwoBitLen - 1) / 32) * 4;
 			nTmp[nTwoByteLen / 4] |= 1U << ((nTwoBitLen - 1) & 0x1f);
 
diff --git a/OpenRA.Mods.Cnc/FileFormats/WsaVideo.cs b/OpenRA.Mods.Cnc/FileFormats/WsaVideo.cs
index 678eca8752..fc1b17f4eb 100644
--- a/OpenRA.Mods.Cnc/FileFormats/WsaVideo.cs
+++ b/OpenRA.Mods.Cnc/FileFormats/WsaVideo.cs
@@ -51,7 +51,7 @@ namespace OpenRA.Mods.Cnc.FileFormats
 			Width = stream.ReadUInt16();
 			Height = stream.ReadUInt16();
 
-			var delta = stream.ReadUInt16() + 37;
+			/*var delta = */stream.ReadUInt16(); /* + 37*/
 			var flags = stream.ReadUInt16();
 
 			frameOffsets = new uint[FrameCount + 2];
diff --git a/OpenRA.Mods.Cnc/Graphics/TeslaZapRenderable.cs b/OpenRA.Mods.Cnc/Graphics/TeslaZapRenderable.cs
index d670794705..20cf122541 100644
--- a/OpenRA.Mods.Cnc/Graphics/TeslaZapRenderable.cs
+++ b/OpenRA.Mods.Cnc/Graphics/TeslaZapRenderable.cs
@@ -109,7 +109,6 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 		static IEnumerable<IFinalizedRenderable> DrawZapWandering(WorldRenderer wr, float2 from, float2 to, ISpriteSequence s, string pal)
 		{
-			var z = float2.Zero;	/* hack */
 			var dist = to - from;
 			var norm = (1f / dist.Length) * new float2(-dist.Y, dist.X);
 
@@ -121,14 +120,14 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 				renderables.AddRange(DrawZap(wr, from, p1, s, out p1, pal));
 				renderables.AddRange(DrawZap(wr, p1, p2, s, out p2, pal));
-				renderables.AddRange(DrawZap(wr, p2, to, s, out z, pal));
+				renderables.AddRange(DrawZap(wr, p2, to, s, out _, pal));
 			}
 			else
 			{
 				var p1 = from + (1 / 2f) * dist + WDist.FromPDF(Game.CosmeticRandom, 2).Length * dist.Length / 4096 * norm;
 
 				renderables.AddRange(DrawZap(wr, from, p1, s, out p1, pal));
-				renderables.AddRange(DrawZap(wr, p1, to, s, out z, pal));
+				renderables.AddRange(DrawZap(wr, p1, to, s, out _, pal));
 			}
 
 			return renderables;
diff --git a/OpenRA.Mods.Cnc/Traits/Disguise.cs b/OpenRA.Mods.Cnc/Traits/Disguise.cs
index 77f0f30f6f..336944f055 100644
--- a/OpenRA.Mods.Cnc/Traits/Disguise.cs
+++ b/OpenRA.Mods.Cnc/Traits/Disguise.cs
@@ -162,7 +162,7 @@ namespace OpenRA.Mods.Cnc.Traits
 			if (!Disguised || self.Owner.IsAlliedWith(self.World.RenderPlayer))
 				return color;
 
-			return color = Game.Settings.Game.UsePlayerStanceColors ? AsPlayer.PlayerRelationshipColor(self) : AsPlayer.Color;
+			return Game.Settings.Game.UsePlayerStanceColors ? AsPlayer.PlayerRelationshipColor(self) : AsPlayer.Color;
 		}
 
 		public void DisguiseAs(Actor target)
diff --git a/OpenRA.Mods.Cnc/UtilityCommands/ImportTSMapCommand.cs b/OpenRA.Mods.Cnc/UtilityCommands/ImportTSMapCommand.cs
index 70ffb4cc0b..c037feb83f 100644
--- a/OpenRA.Mods.Cnc/UtilityCommands/ImportTSMapCommand.cs
+++ b/OpenRA.Mods.Cnc/UtilityCommands/ImportTSMapCommand.cs
@@ -621,8 +621,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 			}
 
 			// Merge Ground into Ambient
-			float ground = 0;
-			if (parsed.TryGetValue("Ground", out ground))
+			if (parsed.TryGetValue("Ground", out var ground))
 			{
 				if (!parsed.ContainsKey("Ambient"))
 					parsed["Ambient"] = 1f;
diff --git a/OpenRA.Mods.Cnc/VideoLoaders/WsaLoader.cs b/OpenRA.Mods.Cnc/VideoLoaders/WsaLoader.cs
index 646933ecf8..333126d0b6 100644
--- a/OpenRA.Mods.Cnc/VideoLoaders/WsaLoader.cs
+++ b/OpenRA.Mods.Cnc/VideoLoaders/WsaLoader.cs
@@ -40,15 +40,15 @@ namespace OpenRA.Mods.Cnc.VideoLoaders
 			if (frames <= 1) // TODO: find a better way to differentiate .shp icons
 				return false;
 
-			var x = s.ReadUInt16();
-			var y = s.ReadUInt16();
+			/* var x = */ s.ReadUInt16();
+			/* var y = */ s.ReadUInt16();
 			var width = s.ReadUInt16();
 			var height = s.ReadUInt16();
 
 			if (width <= 0 || height <= 0)
 				return false;
 
-			var delta = s.ReadUInt16() + 37;
+			/*var delta = */ s.ReadUInt16(); /* + 37;*/
 
 			var flags = s.ReadUInt16();
 
@@ -58,7 +58,7 @@ namespace OpenRA.Mods.Cnc.VideoLoaders
 
 			if (flags == 1)
 			{
-				var palette = s.ReadBytes(768);
+				/* var palette = */ s.ReadBytes(768);
 				for (var i = 0; i < offsets.Length; i++)
 					offsets[i] += 768;
 			}
diff --git a/OpenRA.Mods.Common/Activities/Enter.cs b/OpenRA.Mods.Common/Activities/Enter.cs
index 43e610ac53..e1b1415140 100644
--- a/OpenRA.Mods.Common/Activities/Enter.cs
+++ b/OpenRA.Mods.Common/Activities/Enter.cs
@@ -66,7 +66,6 @@ namespace OpenRA.Mods.Common.Activities
 			if (!targetIsHiddenActor && target.Type == TargetType.Actor)
 				lastVisibleTarget = Target.FromTargetPositions(target);
 
-			var oldUseLastVisibleTarget = useLastVisibleTarget;
 			useLastVisibleTarget = targetIsHiddenActor || !target.IsValidFor(self);
 
 			// Cancel immediately if the target died while we were entering it
diff --git a/OpenRA.Mods.Common/Projectiles/Missile.cs b/OpenRA.Mods.Common/Projectiles/Missile.cs
index 82ccb74d66..9c54deede7 100644
--- a/OpenRA.Mods.Common/Projectiles/Missile.cs
+++ b/OpenRA.Mods.Common/Projectiles/Missile.cs
@@ -355,13 +355,12 @@ namespace OpenRA.Mods.Common.Projectiles
 			var tarDistVec = targetPosition + offset - pos;
 			var relTarHorDist = tarDistVec.HorizontalLength;
 
-			int predClfHgt = 0;
-			int predClfDist = 0;
-			int lastHtChg = 0;
-			int lastHt = 0;
+			var predClfHgt = 0;
+			var predClfDist = 0;
+			var lastHt = 0;
 
 			if (info.TerrainHeightAware)
-				InclineLookahead(world, relTarHorDist, out predClfHgt, out predClfDist, out lastHtChg, out lastHt);
+				InclineLookahead(world, relTarHorDist, out predClfHgt, out predClfDist, out _, out lastHt);
 
 			// Height difference between the incline height and missile height
 			var diffClfMslHgt = predClfHgt - pos.Z;
@@ -590,7 +589,7 @@ namespace OpenRA.Mods.Common.Projectiles
 		int HomingInnerTick(int predClfDist, int diffClfMslHgt, int relTarHorDist, int lastHtChg, int lastHt,
 			int relTarHgt, int vFacing, bool targetPassedBy)
 		{
-			int desiredVFacing = vFacing;
+			int desiredVFacing;
 
 			// Incline coming up -> attempt to reach the incline so that after predClfDist
 			// the height above the terrain is positive but as close to 0 as possible
diff --git a/OpenRA.Mods.Common/Traits/BotModules/Squads/States/AirStates.cs b/OpenRA.Mods.Common/Traits/BotModules/Squads/States/AirStates.cs
index b5381d1cd4..2640a8160a 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/Squads/States/AirStates.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/Squads/States/AirStates.cs
@@ -54,8 +54,7 @@ namespace OpenRA.Mods.Common.Traits.BotModules.Squads
 
 		protected static Actor FindDefenselessTarget(Squad owner)
 		{
-			Actor target = null;
-			FindSafePlace(owner, out target, true);
+			FindSafePlace(owner, out var target, true);
 			return target;
 		}
 
diff --git a/OpenRA.Mods.Common/Traits/Carryall.cs b/OpenRA.Mods.Common/Traits/Carryall.cs
index 398a76fc3c..1d038fb3e1 100644
--- a/OpenRA.Mods.Common/Traits/Carryall.cs
+++ b/OpenRA.Mods.Common/Traits/Carryall.cs
@@ -97,7 +97,6 @@ namespace OpenRA.Mods.Common.Traits
 		readonly AircraftInfo aircraftInfo;
 		readonly Aircraft aircraft;
 		readonly BodyOrientation body;
-		readonly IMove move;
 		readonly IFacing facing;
 		readonly Actor self;
 
@@ -125,7 +124,6 @@ namespace OpenRA.Mods.Common.Traits
 			aircraftInfo = self.Info.TraitInfoOrDefault<AircraftInfo>();
 			aircraft = self.Trait<Aircraft>();
 			body = self.Trait<BodyOrientation>();
-			move = self.Trait<IMove>();
 			facing = self.Trait<IFacing>();
 			this.self = self;
 
@@ -347,7 +345,6 @@ namespace OpenRA.Mods.Common.Traits
 				if (!aircraftInfo.MoveIntoShroud && !self.Owner.Shroud.IsExplored(cell))
 					return;
 
-				var targetLocation = move.NearestMoveableCell(cell);
 				self.QueueActivity(order.Queued, new DeliverUnit(self, order.Target, Info.DropRange, Info.TargetLineColor));
 				self.ShowTargetLines();
 			}
@@ -435,9 +432,7 @@ namespace OpenRA.Mods.Common.Traits
 				if (!info.AllowDropOff || !modifiers.HasModifier(TargetModifiers.ForceMove))
 					return false;
 
-				cursor = info.DropOffCursor;
 				var type = target.Type;
-
 				if ((type == TargetType.Actor && target.Actor.Info.HasTraitInfo<BuildingInfo>())
 					|| (target.Type == TargetType.FrozenActor && target.FrozenActor.Info.HasTraitInfo<BuildingInfo>()))
 				{
diff --git a/OpenRA.Mods.Common/UpdateRules/Rules/20200503/MoveClassicFacingFudge.cs b/OpenRA.Mods.Common/UpdateRules/Rules/20200503/MoveClassicFacingFudge.cs
index d46f65d494..3d35b9b264 100644
--- a/OpenRA.Mods.Common/UpdateRules/Rules/20200503/MoveClassicFacingFudge.cs
+++ b/OpenRA.Mods.Common/UpdateRules/Rules/20200503/MoveClassicFacingFudge.cs
@@ -38,8 +38,6 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 
 		public override IEnumerable<string> UpdateActorNode(ModData modData, MiniYamlNode actorNode)
 		{
-			var modId = modData.Manifest.Id;
-
 			foreach (var bo in actorNode.ChildrenMatching("BodyOrientation"))
 			{
 				var usesClassicFacings = false;
diff --git a/OpenRA.Mods.Common/UpdateRules/Rules/20200503/RenameSelfHealing.cs b/OpenRA.Mods.Common/UpdateRules/Rules/20200503/RenameSelfHealing.cs
index 24903302bc..648f8630dc 100644
--- a/OpenRA.Mods.Common/UpdateRules/Rules/20200503/RenameSelfHealing.cs
+++ b/OpenRA.Mods.Common/UpdateRules/Rules/20200503/RenameSelfHealing.cs
@@ -23,8 +23,6 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 
 		public override IEnumerable<string> UpdateActorNode(ModData modData, MiniYamlNode actorNode)
 		{
-			var modId = modData.Manifest.Id;
-
 			foreach (var sh in actorNode.ChildrenMatching("SelfHealing"))
 			{
 				sh.RenameChildrenMatching("HealIfBelow", "StartIfBelow");
diff --git a/OpenRA.Mods.Common/UtilityCommands/DumpSequenceSheetsCommand.cs b/OpenRA.Mods.Common/UtilityCommands/DumpSequenceSheetsCommand.cs
index e1304a99f5..006e9df687 100644
--- a/OpenRA.Mods.Common/UtilityCommands/DumpSequenceSheetsCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/DumpSequenceSheetsCommand.cs
@@ -34,7 +34,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 
 			var palette = new ImmutablePalette(args[1], new[] { 0 }, Array.Empty<int>());
 
-			SequenceProvider sequences = null;
+			SequenceProvider sequences;
 			var mapPackage = new Folder(Platform.EngineDir).OpenPackage(args[2], modData.ModFiles);
 			if (mapPackage != null)
 				sequences = new Map(modData, mapPackage).Rules.Sequences;
diff --git a/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs b/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
index ced97796b5..82d7fd0c72 100644
--- a/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
@@ -118,8 +118,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 		{
 			var iniFormat = basicSection.GetValue("NewINIFormat", "0");
 
-			var iniFormatVersion = 0;
-			Exts.TryParseIntegerInvariant(iniFormat, out iniFormatVersion);
+			Exts.TryParseIntegerInvariant(iniFormat, out var iniFormatVersion);
 
 			return iniFormatVersion;
 		}
diff --git a/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs b/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs
index d9557c022b..eb025a49ce 100644
--- a/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs
@@ -18,8 +18,6 @@ using OpenRA.Mods.Common.UpdateRules;
 
 namespace OpenRA.Mods.Common.UtilityCommands
 {
-	using YamlFileSet = List<(IReadWritePackage, string, List<MiniYamlNode>)>;
-
 	class UpdateMapCommand : IUtilityCommand
 	{
 		string IUtilityCommand.Name => "--update-map";
@@ -102,15 +100,23 @@ namespace OpenRA.Mods.Common.UtilityCommands
 			var externalFilenames = new HashSet<string>();
 			foreach (var rule in rules)
 			{
-				Console.WriteLine("{0}: {1}", rule.GetType().Name, rule.Name);
-				var mapFiles = new YamlFileSet();
-				var manualSteps = new List<string>();
-
+				Console.WriteLine($"{rule.GetType().Name}: {rule.Name}");
 				Console.Write("   Updating map... ");
 
 				try
 				{
-					manualSteps = UpdateUtils.UpdateMap(modData, mapPackage, rule, out mapFiles, externalFilenames);
+					var manualSteps = UpdateUtils.UpdateMap(modData, mapPackage, rule, out var mapFiles, externalFilenames);
+
+					// Files are saved after each successful automated rule update
+					mapFiles.Save();
+					Console.WriteLine("COMPLETE");
+
+					if (manualSteps.Count > 0)
+					{
+						Console.WriteLine("   Manual changes are required to complete this update:");
+						foreach (var manualStep in manualSteps)
+							Console.WriteLine("    * " + manualStep.Replace("\n", "\n      "));
+					}
 				}
 				catch (Exception ex)
 				{
@@ -119,24 +125,13 @@ namespace OpenRA.Mods.Common.UtilityCommands
 					Console.WriteLine();
 					Console.WriteLine("   The automated changes for this rule were not applied because of an error.");
 					Console.WriteLine("   After the issue reported below is resolved you should run the updater");
-					Console.WriteLine("   with SOURCE set to {0} to retry these changes", rule.GetType().Name);
+					Console.WriteLine($"   with SOURCE set to {rule.GetType().Name} to retry these changes");
 					Console.WriteLine();
 					Console.WriteLine("   The exception reported was:");
 					Console.WriteLine("     " + ex.ToString().Replace("\n", "\n     "));
 					continue;
 				}
 
-				// Files are saved after each successful automated rule update
-				mapFiles.Save();
-				Console.WriteLine("COMPLETE");
-
-				if (manualSteps.Count > 0)
-				{
-					Console.WriteLine("   Manual changes are required to complete this update:");
-					foreach (var manualStep in manualSteps)
-						Console.WriteLine("    * " + manualStep.Replace("\n", "\n      "));
-				}
-
 				Console.WriteLine();
 			}
 
diff --git a/OpenRA.Mods.Common/UtilityCommands/UpdateModCommand.cs b/OpenRA.Mods.Common/UtilityCommands/UpdateModCommand.cs
index a22c8b7767..d6979474c6 100644
--- a/OpenRA.Mods.Common/UtilityCommands/UpdateModCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/UpdateModCommand.cs
@@ -167,9 +167,9 @@ namespace OpenRA.Mods.Common.UtilityCommands
 			foreach (var rule in rules)
 			{
 				var manualSteps = new List<string>();
-				var allFiles = new YamlFileSet();
+				YamlFileSet allFiles;
 
-				LogLine(logWriter, "{0}: {1}", rule.GetType().Name, rule.Name);
+				LogLine(logWriter, $"{rule.GetType().Name}: {rule.Name}");
 
 				try
 				{
diff --git a/OpenRA.Platforms.Default/Sdl2Input.cs b/OpenRA.Platforms.Default/Sdl2Input.cs
index 7f8ba1ec29..d2d77e06e8 100644
--- a/OpenRA.Platforms.Default/Sdl2Input.cs
+++ b/OpenRA.Platforms.Default/Sdl2Input.cs
@@ -221,10 +221,7 @@ namespace OpenRA.Platforms.Default
 			}
 
 			if (pendingMotion != null)
-			{
 				inputHandler.OnMouseInput(pendingMotion.Value);
-				pendingMotion = null;
-			}
 		}
 	}
 }