diff --git a/OpenRA.Game/Actor.cs b/OpenRA.Game/Actor.cs
index f90d0b3465..c795758372 100644
--- a/OpenRA.Game/Actor.cs
+++ b/OpenRA.Game/Actor.cs
@@ -359,8 +359,7 @@ namespace OpenRA
 
 		public override bool Equals(object obj)
 		{
-			var o = obj as Actor;
-			return o != null && Equals(o);
+			return obj is Actor o && Equals(o);
 		}
 
 		public bool Equals(Actor other)
diff --git a/OpenRA.Game/Exts.cs b/OpenRA.Game/Exts.cs
index 9b41efe7b8..8fe5fa5f1a 100644
--- a/OpenRA.Game/Exts.cs
+++ b/OpenRA.Game/Exts.cs
@@ -511,8 +511,7 @@ namespace OpenRA
 
 		public static bool IsTraitEnabled<T>(this T trait)
 		{
-			var disabledTrait = trait as IDisabledTrait;
-			return disabledTrait == null || !disabledTrait.IsTraitDisabled;
+			return !(trait is IDisabledTrait disabledTrait) || !disabledTrait.IsTraitDisabled;
 		}
 
 		public static T FirstEnabledTraitOrDefault<T>(this IEnumerable<T> ts)
diff --git a/OpenRA.Game/GameRules/Ruleset.cs b/OpenRA.Game/GameRules/Ruleset.cs
index 97d4ab5fa9..0035496c71 100644
--- a/OpenRA.Game/GameRules/Ruleset.cs
+++ b/OpenRA.Game/GameRules/Ruleset.cs
@@ -67,8 +67,7 @@ namespace OpenRA
 
 			foreach (var weapon in Weapons)
 			{
-				var projectileLoaded = weapon.Value.Projectile as IRulesetLoaded<WeaponInfo>;
-				if (projectileLoaded != null)
+				if (weapon.Value.Projectile is IRulesetLoaded<WeaponInfo> projectileLoaded)
 				{
 					try
 					{
@@ -82,8 +81,7 @@ namespace OpenRA
 
 				foreach (var warhead in weapon.Value.Warheads)
 				{
-					var cacher = warhead as IRulesetLoaded<WeaponInfo>;
-					if (cacher != null)
+					if (warhead is IRulesetLoaded<WeaponInfo> cacher)
 					{
 						try
 						{
diff --git a/OpenRA.Game/Graphics/Util.cs b/OpenRA.Game/Graphics/Util.cs
index 74a626818f..29239854ec 100644
--- a/OpenRA.Game/Graphics/Util.cs
+++ b/OpenRA.Game/Graphics/Util.cs
@@ -41,8 +41,7 @@ namespace OpenRA.Graphics
 			// See combined.vert for documentation on the channel attribute format
 			var attribC = r.Channel == TextureChannel.RGBA ? 0x02 : ((byte)r.Channel) << 1 | 0x01;
 			attribC |= samplers.X << 6;
-			var ss = r as SpriteWithSecondaryData;
-			if (ss != null)
+			if (r is SpriteWithSecondaryData ss)
 			{
 				sl = ss.SecondaryLeft;
 				st = ss.SecondaryTop;
diff --git a/OpenRA.Game/Input/Hotkey.cs b/OpenRA.Game/Input/Hotkey.cs
index b510cebaca..106a8883d6 100644
--- a/OpenRA.Game/Input/Hotkey.cs
+++ b/OpenRA.Game/Input/Hotkey.cs
@@ -81,8 +81,7 @@ namespace OpenRA
 
 		public override bool Equals(object obj)
 		{
-			var o = obj as Hotkey?;
-			return o != null && o == this;
+			return obj is Hotkey o && (Hotkey?)o == this;
 		}
 
 		public override string ToString() { return "{0} {1}".F(Key, Modifiers.ToString("F")); }
diff --git a/OpenRA.Game/Map/MapCache.cs b/OpenRA.Game/Map/MapCache.cs
index 7ea2a59280..1cf099d506 100644
--- a/OpenRA.Game/Map/MapCache.cs
+++ b/OpenRA.Game/Map/MapCache.cs
@@ -148,8 +148,7 @@ namespace OpenRA
 				{
 					foreach (var map in package.Contents)
 					{
-						var mapPackage = package.OpenPackage(map, modData.ModFiles) as IReadWritePackage;
-						if (mapPackage != null)
+						if (package.OpenPackage(map, modData.ModFiles) is IReadWritePackage mapPackage)
 							yield return mapPackage;
 					}
 				}
diff --git a/OpenRA.Game/Primitives/SegmentStream.cs b/OpenRA.Game/Primitives/SegmentStream.cs
index f1bdce4f30..8b1a1c1c46 100644
--- a/OpenRA.Game/Primitives/SegmentStream.cs
+++ b/OpenRA.Game/Primitives/SegmentStream.cs
@@ -131,8 +131,7 @@ namespace OpenRA.Primitives
 		{
 			var offset = 0L;
 			overallBaseStream = stream;
-			var segmentStream = stream as SegmentStream;
-			if (segmentStream != null)
+			if (stream is SegmentStream segmentStream)
 				offset += segmentStream.BaseOffset + GetOverallNestedOffset(segmentStream.BaseStream, out overallBaseStream);
 			return offset;
 		}
diff --git a/OpenRA.Game/Primitives/float3.cs b/OpenRA.Game/Primitives/float3.cs
index 45de826ff5..94253dc8f2 100644
--- a/OpenRA.Game/Primitives/float3.cs
+++ b/OpenRA.Game/Primitives/float3.cs
@@ -55,8 +55,7 @@ namespace OpenRA
 
 		public override bool Equals(object obj)
 		{
-			var o = obj as float3?;
-			return o != null && o == this;
+			return obj is float3 o && (float3?)o == this;
 		}
 
 		public override string ToString() { return "{0},{1},{2}".F(X, Y, Z); }
diff --git a/OpenRA.Game/Support/ExceptionHandler.cs b/OpenRA.Game/Support/ExceptionHandler.cs
index bed6f3dee4..7db23ec89f 100644
--- a/OpenRA.Game/Support/ExceptionHandler.cs
+++ b/OpenRA.Game/Support/ExceptionHandler.cs
@@ -63,13 +63,11 @@ namespace OpenRA
 
 			sb.AppendIndentedFormatLine(indent, "Exception of type `{0}`: {1}", ex.GetType().FullName, ex.Message);
 
-			var tle = ex as TypeLoadException;
-			var oom = ex as OutOfMemoryException;
-			if (tle != null)
+			if (ex is TypeLoadException tle)
 			{
 				sb.AppendIndentedFormatLine(indent, "TypeName=`{0}`", tle.TypeName);
 			}
-			else if (oom != null)
+			else if (ex is OutOfMemoryException)
 			{
 				var gcMemoryBeforeCollect = GC.GetTotalMemory(false);
 				GC.Collect();
diff --git a/OpenRA.Game/Widgets/Widget.cs b/OpenRA.Game/Widgets/Widget.cs
index e32c114a9a..737d69cf33 100644
--- a/OpenRA.Game/Widgets/Widget.cs
+++ b/OpenRA.Game/Widgets/Widget.cs
@@ -73,11 +73,10 @@ namespace OpenRA.Widgets
 
 		public static T LoadWidget<T>(string id, Widget parent, WidgetArgs args) where T : Widget
 		{
-			var widget = LoadWidget(id, parent, args) as T;
-			if (widget == null)
-				throw new InvalidOperationException(
-					"Widget {0} is not of type {1}".F(id, typeof(T).Name));
-			return widget;
+			if (LoadWidget(id, parent, args) is T widget)
+				return widget;
+
+			throw new InvalidOperationException("Widget {0} is not of type {1}".F(id, typeof(T).Name));
 		}
 
 		public static Widget LoadWidget(string id, Widget parent, WidgetArgs args)
diff --git a/OpenRA.Game/World.cs b/OpenRA.Game/World.cs
index 718ba0c274..3afaa404e7 100644
--- a/OpenRA.Game/World.cs
+++ b/OpenRA.Game/World.cs
@@ -273,8 +273,7 @@ namespace OpenRA
 
 			gameInfo.DisabledSpawnPoints = OrderManager.LobbyInfo.DisabledSpawnPoints;
 
-			var echo = OrderManager.Connection as EchoConnection;
-			var rc = echo != null ? echo.Recorder : null;
+			var rc = (OrderManager.Connection as EchoConnection)?.Recorder;
 
 			if (rc != null)
 				rc.Metadata = new ReplayMetadata(gameInfo);
@@ -326,12 +325,10 @@ namespace OpenRA
 		{
 			effects.Add(e);
 
-			var sp = e as ISpatiallyPartitionable;
-			if (sp == null)
+			if (!(e is ISpatiallyPartitionable))
 				unpartitionedEffects.Add(e);
 
-			var se = e as ISync;
-			if (se != null)
+			if (e is ISync se)
 				syncedEffects.Add(se);
 		}
 
@@ -339,12 +336,10 @@ namespace OpenRA
 		{
 			effects.Remove(e);
 
-			var sp = e as ISpatiallyPartitionable;
-			if (sp == null)
+			if (!(e is ISpatiallyPartitionable))
 				unpartitionedEffects.Remove(e);
 
-			var se = e as ISync;
-			if (se != null)
+			if (e is ISync se)
 				syncedEffects.Remove(se);
 		}
 
diff --git a/OpenRA.Mods.Cnc/Traits/SupportPowers/GrantPrerequisiteChargeDrainPower.cs b/OpenRA.Mods.Cnc/Traits/SupportPowers/GrantPrerequisiteChargeDrainPower.cs
index beea440fce..798938622d 100644
--- a/OpenRA.Mods.Cnc/Traits/SupportPowers/GrantPrerequisiteChargeDrainPower.cs
+++ b/OpenRA.Mods.Cnc/Traits/SupportPowers/GrantPrerequisiteChargeDrainPower.cs
@@ -183,19 +183,19 @@ namespace OpenRA.Mods.Cnc.Traits
 
 			public override string IconOverlayTextOverride()
 			{
-				var info = Info as GrantPrerequisiteChargeDrainPowerInfo;
-				if (info == null || !Active)
+				if (!Active)
 					return null;
 
+				var info = (GrantPrerequisiteChargeDrainPowerInfo)Info;
 				return active ? info.ActiveText : available ? info.AvailableText : null;
 			}
 
 			public override string TooltipTimeTextOverride()
 			{
-				var info = Info as GrantPrerequisiteChargeDrainPowerInfo;
-				if (info == null || !Active)
+				if (!Active)
 					return null;
 
+				var info = (GrantPrerequisiteChargeDrainPowerInfo)Info;
 				return active ? info.ActiveText : available ? info.AvailableText : null;
 			}
 		}
diff --git a/OpenRA.Mods.Common/Activities/Attack.cs b/OpenRA.Mods.Common/Activities/Attack.cs
index 15dbfa1295..db96a02b25 100644
--- a/OpenRA.Mods.Common/Activities/Attack.cs
+++ b/OpenRA.Mods.Common/Activities/Attack.cs
@@ -197,10 +197,9 @@ namespace OpenRA.Mods.Common.Activities
 			maxRange = armaments.Min(a => a.MaxRange());
 
 			var pos = self.CenterPosition;
-			var mobile = move as Mobile;
 			if (!target.IsInRange(pos, maxRange)
 				|| (minRange.Length != 0 && target.IsInRange(pos, minRange))
-				|| (mobile != null && !mobile.CanInteractWithGroundLayer(self)))
+				|| (move is Mobile mobile && !mobile.CanInteractWithGroundLayer(self)))
 			{
 				// Try to move within range, drop the target otherwise
 				if (move == null)
diff --git a/OpenRA.Mods.Common/ActorInitializer.cs b/OpenRA.Mods.Common/ActorInitializer.cs
index 06ffbfc345..90fa82b052 100644
--- a/OpenRA.Mods.Common/ActorInitializer.cs
+++ b/OpenRA.Mods.Common/ActorInitializer.cs
@@ -102,12 +102,8 @@ namespace OpenRA.Mods.Common
 
 		public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
 		{
-			if (destinationType == typeof(string))
-			{
-				var reference = value as ActorInitActorReference;
-				if (reference != null)
-					return reference.InternalName;
-			}
+			if (destinationType == typeof(string) && value is ActorInitActorReference reference)
+				return reference.InternalName;
 
 			return base.ConvertTo(context, culture, value, destinationType);
 		}
diff --git a/OpenRA.Mods.Common/Effects/FlashTarget.cs b/OpenRA.Mods.Common/Effects/FlashTarget.cs
index 95431eb8a1..3daf44501e 100644
--- a/OpenRA.Mods.Common/Effects/FlashTarget.cs
+++ b/OpenRA.Mods.Common/Effects/FlashTarget.cs
@@ -34,8 +34,7 @@ namespace OpenRA.Mods.Common.Effects
 
 			target.World.RemoveAll(effect =>
 			{
-				var flashTarget = effect as FlashTarget;
-				return flashTarget != null && flashTarget.target == target;
+				return effect is FlashTarget flashTarget && flashTarget.target == target;
 			});
 		}
 
diff --git a/OpenRA.Mods.Common/Lint/CheckAngle.cs b/OpenRA.Mods.Common/Lint/CheckAngle.cs
index 6737d33445..3dfa4f9441 100644
--- a/OpenRA.Mods.Common/Lint/CheckAngle.cs
+++ b/OpenRA.Mods.Common/Lint/CheckAngle.cs
@@ -20,8 +20,7 @@ namespace OpenRA.Mods.Common.Lint
 		{
 			foreach (var weaponInfo in rules.Weapons)
 			{
-				var missile = weaponInfo.Value.Projectile as MissileInfo;
-				if (missile != null)
+				if (weaponInfo.Value.Projectile is MissileInfo missile)
 				{
 					var minAngle = missile.MinimumLaunchAngle.Angle;
 					var maxAngle = missile.MaximumLaunchAngle.Angle;
@@ -31,8 +30,7 @@ namespace OpenRA.Mods.Common.Lint
 					CheckLaunchAngles(weaponInfo.Key, minAngle, testMaxAngle, maxAngle, emitError);
 				}
 
-				var bullet = weaponInfo.Value.Projectile as BulletInfo;
-				if (bullet != null)
+				if (weaponInfo.Value.Projectile is BulletInfo bullet)
 				{
 					var minAngle = bullet.LaunchAngle[0].Angle;
 					var maxAngle = bullet.LaunchAngle.Length > 1 ? bullet.LaunchAngle[1].Angle : minAngle;
diff --git a/OpenRA.Mods.Common/Lint/CheckRangeLimit.cs b/OpenRA.Mods.Common/Lint/CheckRangeLimit.cs
index 132cf25f3b..9cc4539725 100644
--- a/OpenRA.Mods.Common/Lint/CheckRangeLimit.cs
+++ b/OpenRA.Mods.Common/Lint/CheckRangeLimit.cs
@@ -21,9 +21,8 @@ namespace OpenRA.Mods.Common.Lint
 			foreach (var weaponInfo in rules.Weapons)
 			{
 				var range = weaponInfo.Value.Range;
-				var missile = weaponInfo.Value.Projectile as MissileInfo;
 
-				if (missile != null && missile.RangeLimit > WDist.Zero && missile.RangeLimit < range)
+				if (weaponInfo.Value.Projectile is MissileInfo missile && missile.RangeLimit > WDist.Zero && missile.RangeLimit < range)
 					emitError("Weapon `{0}`: projectile RangeLimit lower than weapon range!"
 						.F(weaponInfo.Key));
 			}
diff --git a/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs b/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs
index a55b7a3d6c..581a4237e3 100644
--- a/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs
+++ b/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs
@@ -325,8 +325,7 @@ namespace OpenRA.Mods.Common.Orders
 			foreach (var blocker in blockers)
 			{
 				CPos moveCell;
-				var mobile = blocker.Trait as Mobile;
-				if (mobile != null)
+				if (blocker.Trait is Mobile mobile)
 				{
 					var availableCells = adjacentTiles.Where(t => mobile.CanEnterCell(t)).ToList();
 					if (availableCells.Count == 0)
diff --git a/OpenRA.Mods.Common/Scripting/Global/ActorGlobal.cs b/OpenRA.Mods.Common/Scripting/Global/ActorGlobal.cs
index 3a808d8783..6d20230d44 100644
--- a/OpenRA.Mods.Common/Scripting/Global/ActorGlobal.cs
+++ b/OpenRA.Mods.Common/Scripting/Global/ActorGlobal.cs
@@ -40,9 +40,7 @@ namespace OpenRA.Mods.Common.Scripting
 			if (initInstance.Length > 1)
 				initType.GetField("InstanceName").SetValue(init, initInstance[1]);
 
-			var compositeInit = init as CompositeActorInit;
-			var tableValue = value as LuaTable;
-			if (tableValue != null && compositeInit != null)
+			if (value is LuaTable tableValue && init is CompositeActorInit compositeInit)
 			{
 				var args = compositeInit.InitializeArgs();
 				var initValues = new Dictionary<string, object>();
@@ -74,8 +72,7 @@ namespace OpenRA.Mods.Common.Scripting
 			}
 
 			// HACK: Backward compatibility for legacy int facings
-			var facingInit = init as FacingInit;
-			if (facingInit != null)
+			if (init is FacingInit facingInit)
 			{
 				if (value.TryGetClrValue(out int facing))
 				{
diff --git a/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs b/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs
index a37ddd921a..7f2ef22312 100644
--- a/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs
+++ b/OpenRA.Mods.Common/Traits/BotModules/HarvesterBotModule.cs
@@ -117,10 +117,8 @@ namespace OpenRA.Mods.Common.Traits
 			{
 				if (!h.Key.IsIdle)
 				{
-					var act = h.Key.CurrentActivity as FindAndDeliverResources;
-
 					// Ignore this actor if FindAndDeliverResources is working fine or it is performing a different activity
-					if (act == null || !act.LastSearchFailed)
+					if (!(h.Key.CurrentActivity is FindAndDeliverResources act) || !act.LastSearchFailed)
 						continue;
 				}
 
diff --git a/OpenRA.Mods.Common/Traits/Buildings/TransformsIntoTransforms.cs b/OpenRA.Mods.Common/Traits/Buildings/TransformsIntoTransforms.cs
index b672cb40d5..f0216fb430 100644
--- a/OpenRA.Mods.Common/Traits/Buildings/TransformsIntoTransforms.cs
+++ b/OpenRA.Mods.Common/Traits/Buildings/TransformsIntoTransforms.cs
@@ -36,8 +36,7 @@ namespace OpenRA.Mods.Common.Traits
 			// The DeployTransform order does not have a position associated with it,
 			// so we can only queue a new transformation if something else has
 			// already triggered the undeploy.
-			var currentTransform = self.CurrentActivity as Transform;
-			if (!order.Queued || currentTransform == null)
+			if (!order.Queued || !(self.CurrentActivity is Transform currentTransform))
 				return;
 
 			if (!order.Queued)
diff --git a/OpenRA.Mods.Common/Traits/CombatDebugOverlay.cs b/OpenRA.Mods.Common/Traits/CombatDebugOverlay.cs
index 94b2197e42..7185aba9fb 100644
--- a/OpenRA.Mods.Common/Traits/CombatDebugOverlay.cs
+++ b/OpenRA.Mods.Common/Traits/CombatDebugOverlay.cs
@@ -91,8 +91,7 @@ namespace OpenRA.Mods.Common.Traits
 		IEnumerable<IRenderable> RenderArmaments(Actor self, AttackBase attack)
 		{
 			// Fire ports on garrisonable structures
-			var garrison = attack as AttackGarrisoned;
-			if (garrison != null)
+			if (attack is AttackGarrisoned garrison)
 			{
 				var bodyOrientation = coords.Value.QuantizeOrientation(self, self.Orientation);
 				foreach (var p in garrison.Info.Ports)
diff --git a/OpenRA.Mods.Common/Traits/World/EditorActorPreview.cs b/OpenRA.Mods.Common/Traits/World/EditorActorPreview.cs
index 6db86f7b4c..ba844cd03e 100644
--- a/OpenRA.Mods.Common/Traits/World/EditorActorPreview.cs
+++ b/OpenRA.Mods.Common/Traits/World/EditorActorPreview.cs
@@ -209,12 +209,10 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			Func<object, bool> saveInit = init =>
 			{
-				var factionInit = init as FactionInit;
-				if (factionInit != null && factionInit.Value == Owner.Faction)
+				if (init is FactionInit factionInit && factionInit.Value == Owner.Faction)
 					return false;
 
-				var healthInit = init as HealthInit;
-				if (healthInit != null && healthInit.Value == 100)
+				if (init is HealthInit healthInit && healthInit.Value == 100)
 					return false;
 
 				// TODO: Other default values will need to be filtered
diff --git a/OpenRA.Mods.Common/Traits/World/Locomotor.cs b/OpenRA.Mods.Common/Traits/World/Locomotor.cs
index 1a6bfd8264..db36c49a99 100644
--- a/OpenRA.Mods.Common/Traits/World/Locomotor.cs
+++ b/OpenRA.Mods.Common/Traits/World/Locomotor.cs
@@ -303,8 +303,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (check <= BlockedByActor.Immovable && cellFlag.HasCellFlag(CellFlag.HasMovableActor) &&
 				actor.Owner.RelationshipWith(otherActor.Owner) == PlayerRelationship.Ally)
 			{
-				var mobile = otherActor.OccupiesSpace as Mobile;
-				if (mobile != null && !mobile.IsTraitDisabled && !mobile.IsTraitPaused && !mobile.IsImmovable)
+				if (otherActor.OccupiesSpace is Mobile mobile && !mobile.IsTraitDisabled && !mobile.IsTraitPaused && !mobile.IsImmovable)
 					return false;
 			}
 
@@ -324,8 +323,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (cellFlag.HasCellFlag(CellFlag.HasTransitOnlyActor))
 			{
 				// Transit only tiles should not block movement
-				var building = otherActor.OccupiesSpace as Building;
-				if (building != null && building.TransitOnlyCells().Contains(cell))
+				if (otherActor.OccupiesSpace is Building building && building.TransitOnlyCells().Contains(cell))
 					return false;
 			}
 
@@ -346,16 +344,11 @@ namespace OpenRA.Mods.Common.Traits
 		static bool IsMoving(Actor self, Actor other)
 		{
 			// PERF: Because we can be sure that OccupiesSpace is Mobile here we can save some performance by avoiding querying for the trait.
-			var otherMobile = other.OccupiesSpace as Mobile;
-			if (otherMobile == null || !otherMobile.CurrentMovementTypes.HasMovementType(MovementType.Horizontal))
+			if (!(other.OccupiesSpace is Mobile otherMobile) || !otherMobile.CurrentMovementTypes.HasMovementType(MovementType.Horizontal))
 				return false;
 
 			// PERF: Same here.
-			var selfMobile = self.OccupiesSpace as Mobile;
-			if (selfMobile == null)
-				return false;
-
-			return true;
+			return self.OccupiesSpace is Mobile;
 		}
 
 		public void WorldLoaded(World w, WorldRenderer wr)
@@ -466,8 +459,7 @@ namespace OpenRA.Mods.Common.Traits
 					var isMovable = mobile != null && !mobile.IsTraitDisabled && !mobile.IsTraitPaused && !mobile.IsImmovable;
 					var isMoving = isMovable && mobile.CurrentMovementTypes.HasMovementType(MovementType.Horizontal);
 
-					var building = actor.OccupiesSpace as Building;
-					var isTransitOnly = building != null && building.TransitOnlyCells().Contains(cell);
+					var isTransitOnly = actor.OccupiesSpace is Building building && building.TransitOnlyCells().Contains(cell);
 
 					if (isTransitOnly)
 					{
diff --git a/OpenRA.Mods.Common/Traits/World/TerrainRenderer.cs b/OpenRA.Mods.Common/Traits/World/TerrainRenderer.cs
index b60d0179a5..b4b655fda6 100644
--- a/OpenRA.Mods.Common/Traits/World/TerrainRenderer.cs
+++ b/OpenRA.Mods.Common/Traits/World/TerrainRenderer.cs
@@ -158,8 +158,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		IEnumerable<IRenderable> ITiledTerrainRenderer.RenderUIPreview(WorldRenderer wr, TerrainTemplateInfo t, int2 origin, float scale)
 		{
-			var template = t as DefaultTerrainTemplateInfo;
-			if (template == null)
+			if (!(t is DefaultTerrainTemplateInfo template))
 				yield break;
 
 			var ts = map.Grid.TileSize;
diff --git a/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs b/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs
index 744b320129..92eb777d66 100644
--- a/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/UpdateMapCommand.cs
@@ -36,8 +36,8 @@ namespace OpenRA.Mods.Common.UtilityCommands
 			var modData = Game.ModData = utility.ModData;
 
 			// HACK: We know that maps can only be oramap or folders, which are ReadWrite
-			var package = new Folder(Platform.EngineDir).OpenPackage(args[1], modData.ModFiles) as IReadWritePackage;
-			if (package == null)
+			var folder = new Folder(Platform.EngineDir);
+			if (!(folder.OpenPackage(args[1], modData.ModFiles) is IReadWritePackage package))
 				throw new FileNotFoundException(args[1]);
 
 			IEnumerable<UpdateRule> rules = null;
diff --git a/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
index 1c6cbce502..ef83c18ba2 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
@@ -371,9 +371,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				currentPackage = package;
 				currentFilename = filename;
 				var prefix = "";
-				var fs = modData.DefaultFileSystem as OpenRA.FileSystem.FileSystem;
 
-				if (fs != null)
+				if (modData.DefaultFileSystem is OpenRA.FileSystem.FileSystem fs)
 				{
 					prefix = fs.GetPrefix(package);
 					if (prefix != null)
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Editor/SaveMapLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Editor/SaveMapLogic.cs
index 0fdd42b775..cbf5ba190c 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Editor/SaveMapLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Editor/SaveMapLogic.cs
@@ -180,8 +180,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 
 				try
 				{
-					var package = map.Package as IReadWritePackage;
-					if (package == null || package.Name != combinedPath)
+					if (!(map.Package is IReadWritePackage package) || package.Name != combinedPath)
 					{
 						selectedDirectory.Folder.Delete(combinedPath);
 						if (fileType == MapFileType.OraMap)
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Ingame/CommandBarLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Ingame/CommandBarLogic.cs
index 9096042f86..6b286c9337 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Ingame/CommandBarLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Ingame/CommandBarLogic.cs
@@ -273,12 +273,10 @@ namespace OpenRA.Mods.Common.Widgets
 
 		bool IsForceModifiersActive(Modifiers modifiers)
 		{
-			var fmog = world.OrderGenerator as ForceModifiersOrderGenerator;
-			if (fmog != null && fmog.Modifiers.HasFlag(modifiers))
+			if (world.OrderGenerator is ForceModifiersOrderGenerator fmog && fmog.Modifiers.HasFlag(modifiers))
 				return true;
 
-			var uog = world.OrderGenerator as UnitOrderGenerator;
-			if (uog != null && Game.GetModifierKeys().HasFlag(modifiers))
+			if (world.OrderGenerator is UnitOrderGenerator uog && Game.GetModifierKeys().HasFlag(modifiers))
 				return true;
 
 			return false;
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Ingame/GameTimerLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Ingame/GameTimerLogic.cs
index 57a48b1c74..ad83c2b72a 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Ingame/GameTimerLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Ingame/GameTimerLogic.cs
@@ -65,8 +65,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				status.GetText = statusText;
 			}
 
-			var timerTooltip = timer as LabelWithTooltipWidget;
-			if (timerTooltip != null)
+			if (timer is LabelWithTooltipWidget timerTooltip)
 			{
 				var connection = orderManager.Connection as ReplayConnection;
 				if (connection != null && connection.FinalGameTick != 0)
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Ingame/OrderButtonsChromeLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Ingame/OrderButtonsChromeLogic.cs
index 2817f2b1f0..3d031702a3 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Ingame/OrderButtonsChromeLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Ingame/OrderButtonsChromeLogic.cs
@@ -19,8 +19,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		[ObjectCreator.UseCtor]
 		public SellOrderButtonLogic(Widget widget, World world)
 		{
-			var sell = widget as ButtonWidget;
-			if (sell != null)
+			if (widget is ButtonWidget sell)
 				OrderButtonsChromeUtils.BindOrderButton<SellOrderGenerator>(world, sell, "sell");
 		}
 	}
@@ -30,8 +29,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		[ObjectCreator.UseCtor]
 		public RepairOrderButtonLogic(Widget widget, World world)
 		{
-			var repair = widget as ButtonWidget;
-			if (repair != null)
+			if (widget is ButtonWidget repair)
 				OrderButtonsChromeUtils.BindOrderButton<RepairOrderGenerator>(world, repair, "repair");
 		}
 	}
@@ -41,8 +39,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		[ObjectCreator.UseCtor]
 		public PowerdownOrderButtonLogic(Widget widget, World world)
 		{
-			var power = widget as ButtonWidget;
-			if (power != null)
+			if (widget is ButtonWidget power)
 				OrderButtonsChromeUtils.BindOrderButton<PowerDownOrderGenerator>(world, power, "power");
 		}
 	}
@@ -52,8 +49,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 		[ObjectCreator.UseCtor]
 		public BeaconOrderButtonLogic(Widget widget, World world)
 		{
-			var beacon = widget as ButtonWidget;
-			if (beacon != null)
+			if (widget is ButtonWidget beacon)
 				OrderButtonsChromeUtils.BindOrderButton<BeaconOrderGenerator>(world, beacon, "beacon");
 		}
 	}
diff --git a/OpenRA.Mods.Common/Widgets/ScrollPanelWidget.cs b/OpenRA.Mods.Common/Widgets/ScrollPanelWidget.cs
index 76b4f7d432..5263c8a3cf 100644
--- a/OpenRA.Mods.Common/Widgets/ScrollPanelWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/ScrollPanelWidget.cs
@@ -282,8 +282,7 @@ namespace OpenRA.Mods.Common.Widgets
 		{
 			var item = Children.FirstOrDefault(c =>
 			{
-				var si = c as ScrollItemWidget;
-				return si != null && si.ItemKey == itemKey;
+				return c is ScrollItemWidget si && si.ItemKey == itemKey;
 			});
 
 			if (item != null)
@@ -294,8 +293,7 @@ namespace OpenRA.Mods.Common.Widgets
 		{
 			var item = Children.FirstOrDefault(c =>
 			{
-				var si = c as ScrollItemWidget;
-				return si != null && si.IsSelected();
+				return c is ScrollItemWidget si && si.IsSelected();
 			});
 
 			if (item != null)
diff --git a/OpenRA.Mods.Common/Widgets/WorldInteractionControllerWidget.cs b/OpenRA.Mods.Common/Widgets/WorldInteractionControllerWidget.cs
index d8995e269d..3c7a92c8d5 100644
--- a/OpenRA.Mods.Common/Widgets/WorldInteractionControllerWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/WorldInteractionControllerWidget.cs
@@ -88,9 +88,8 @@ namespace OpenRA.Mods.Common.Widgets
 			var useClassicMouseStyle = Game.Settings.Game.UseClassicMouseStyle;
 
 			var multiClick = mi.MultiTapCount >= 2;
-			var uog = World.OrderGenerator as UnitOrderGenerator;
 
-			if (uog == null)
+			if (!(World.OrderGenerator is UnitOrderGenerator uog))
 			{
 				ApplyOrders(World, mi);
 				isDragging = false;
diff --git a/OpenRA.Mods.D2k/Traits/Buildings/D2kBuilding.cs b/OpenRA.Mods.D2k/Traits/Buildings/D2kBuilding.cs
index 5ac636d1ce..0dc9b6acb5 100644
--- a/OpenRA.Mods.D2k/Traits/Buildings/D2kBuilding.cs
+++ b/OpenRA.Mods.D2k/Traits/Buildings/D2kBuilding.cs
@@ -83,8 +83,7 @@ namespace OpenRA.Mods.D2k.Traits.Buildings
 			{
 				var map = self.World.Map;
 
-				var terrainInfo = self.World.Map.Rules.TerrainInfo as ITemplatedTerrainInfo;
-				if (terrainInfo == null)
+				if (!(self.World.Map.Rules.TerrainInfo is ITemplatedTerrainInfo terrainInfo))
 					throw new InvalidDataException("D2kBuilding requires a template-based tileset.");
 
 				var template = terrainInfo.Templates[info.ConcreteTemplate];
diff --git a/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs b/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
index b856773f35..345b228e8c 100644
--- a/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
+++ b/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
@@ -354,14 +354,13 @@ namespace OpenRA.Platforms.Default
 		public void SetHardwareCursor(IHardwareCursor cursor)
 		{
 			VerifyThreadAffinity();
-			var c = cursor as Sdl2HardwareCursor;
-			if (c == null)
-				SDL.SDL_ShowCursor((int)SDL.SDL_bool.SDL_FALSE);
-			else
+			if (cursor is Sdl2HardwareCursor c)
 			{
 				SDL.SDL_ShowCursor((int)SDL.SDL_bool.SDL_TRUE);
 				SDL.SDL_SetCursor(c.Cursor);
 			}
+			else
+				SDL.SDL_ShowCursor((int)SDL.SDL_bool.SDL_FALSE);
 		}
 
 		public void SetRelativeMouseMode(bool mode)