Use Null-Propagation Operator

OpenRA.Game/Activities/Activity.cs

@@ -185,8 +185,7 @@ namespace OpenRA.Activities
 		/// </summary>
 		internal void OnActorDisposeOuter(Actor self)
 		{
-			if (ChildActivity != null)
-				ChildActivity.OnActorDisposeOuter(self);
+			ChildActivity?.OnActorDisposeOuter(self);
 
 			OnActorDispose(self);
 		}
@@ -199,8 +198,7 @@ namespace OpenRA.Activities
 			if (!IsInterruptible)
 				return;
 
-			if (ChildActivity != null)
-				ChildActivity.Cancel(self);
+			ChildActivity?.Cancel(self);
 
 			// Directly mark activities that are queued and therefore didn't run yet as done
 			State = State == ActivityState.Queued ? ActivityState.Done : ActivityState.Canceling;
@@ -243,11 +241,9 @@ namespace OpenRA.Activities
 
 				Console.WriteLine(GetType().ToString().Split('.').Last());
 
-				if (ChildActivity != null)
-					ChildActivity.PrintActivityTree(self, origin, level + 1);
+				ChildActivity?.PrintActivityTree(self, origin, level + 1);
 
-				if (NextActivity != null)
-					NextActivity.PrintActivityTree(self, origin, level);
+				NextActivity?.PrintActivityTree(self, origin, level);
 			}
 		}
 

OpenRA.Game/Activities/CallFunc.cs

@@ -26,7 +26,7 @@ namespace OpenRA.Activities
 
 		public override bool Tick(Actor self)
 		{
-			if (a != null) a();
+			a?.Invoke();
 			return true;
 		}
 	}

OpenRA.Game/Actor.cs

@@ -329,8 +329,7 @@ namespace OpenRA
 
 		public void CancelActivity()
 		{
-			if (CurrentActivity != null)
-				CurrentActivity.Cancel(this);
+			CurrentActivity?.Cancel(this);
 		}
 
 		public override int GetHashCode()
@@ -382,8 +381,7 @@ namespace OpenRA
 		{
 			// If CurrentActivity isn't null, run OnActorDisposeOuter in case some cleanups are needed.
 			// This should be done before the FrameEndTask to avoid dependency issues.
-			if (CurrentActivity != null)
-				CurrentActivity.OnActorDisposeOuter(this);
+			CurrentActivity?.OnActorDisposeOuter(this);
 
 			// Allow traits/activities to prevent a race condition when they depend on disposing the actor (e.g. Transforms)
 			WillDispose = true;
@@ -402,8 +400,7 @@ namespace OpenRA
 				World.TraitDict.RemoveActor(this);
 				Disposed = true;
 
-				if (luaInterface != null)
-					luaInterface.Value.OnActorDestroyed();
+				luaInterface?.Value.OnActorDestroyed();
 			});
 		}
 

OpenRA.Game/Download.cs

@@ -90,8 +90,7 @@ namespace OpenRA
 		public void CancelAsync()
 		{
 			lock (syncObject)
-				if (wc != null)
-					wc.CancelAsync();
+				wc?.CancelAsync();
 		}
 	}
 }

OpenRA.Game/FieldLoader.cs

@@ -179,8 +179,7 @@ namespace OpenRA
 
 		public static object GetValue(string fieldName, Type fieldType, MiniYaml yaml, MemberInfo field)
 		{
-			var value = yaml.Value;
-			if (value != null) value = value.Trim();
+			var value = yaml.Value?.Trim();
 
 			if (fieldType == typeof(int))
 			{

OpenRA.Game/FileSystem/FileSystem.cs

@@ -197,10 +197,7 @@ namespace OpenRA.FileSystem
 			var package = fileIndex[filename]
 				.LastOrDefault(x => x.Contains(filename));
 
-			if (package != null)
-				return package.GetStream(filename);
-
-			return null;
+			return package?.GetStream(filename);
 		}
 
 		public Stream Open(string filename)

OpenRA.Game/FileSystem/ZipFile.cs

@@ -66,8 +66,7 @@ namespace OpenRA.FileSystem
 
 			public void Dispose()
 			{
-				if (pkg != null)
-					pkg.Close();
+				pkg?.Close();
 			}
 
 			public IReadOnlyPackage OpenPackage(string filename, FileSystem context)

OpenRA.Game/Game.cs

@@ -80,7 +80,7 @@ namespace OpenRA
 
 		static void JoinInner(OrderManager om)
 		{
-			if (OrderManager != null) OrderManager.Dispose();
+			OrderManager?.Dispose();
 			OrderManager = om;
 			lastConnectionState = ConnectionState.PreConnecting;
 			ConnectionStateChanged(OrderManager);
@@ -154,8 +154,7 @@ namespace OpenRA
 		internal static void StartGame(string mapUID, WorldType type)
 		{
 			// Dispose of the old world before creating a new one.
-			if (worldRenderer != null)
-				worldRenderer.Dispose();
+			worldRenderer?.Dispose();
 
 			Cursor.SetCursor(null);
 			BeforeGameStart();
@@ -330,11 +329,9 @@ namespace OpenRA
 					Log.Write("graphics", "{0}", e);
 					Console.WriteLine("Renderer initialization failed. Check graphics.log for details.");
 
-					if (Renderer != null)
-						Renderer.Dispose();
+					Renderer?.Dispose();
 
-					if (Sound != null)
-						Sound.Dispose();
+					Sound?.Dispose();
 				}
 			}
 
@@ -388,13 +385,10 @@ namespace OpenRA
 
 			Ui.ResetAll();
 
-			if (worldRenderer != null)
-				worldRenderer.Dispose();
+			worldRenderer?.Dispose();
 			worldRenderer = null;
-			if (server != null)
-				server.Shutdown();
-			if (OrderManager != null)
-				OrderManager.Dispose();
+			server?.Shutdown();
+			OrderManager?.Dispose();
 
 			if (ModData != null)
 			{
@@ -430,8 +424,7 @@ namespace OpenRA
 			var grid = ModData.Manifest.Contains<MapGrid>() ? ModData.Manifest.Get<MapGrid>() : null;
 			Renderer.InitializeDepthBuffer(grid);
 
-			if (Cursor != null)
-				Cursor.Dispose();
+			Cursor?.Dispose();
 
 			Cursor = new CursorManager(ModData.CursorProvider);
 
@@ -446,8 +439,7 @@ namespace OpenRA
 
 			try
 			{
-				if (discoverNat != null)
-					discoverNat.Wait();
+				discoverNat?.Wait();
 			}
 			catch (Exception e)
 			{
@@ -610,8 +602,7 @@ namespace OpenRA
 						Sync.RunUnsynced(Settings.Debug.SyncCheckUnsyncedCode, world, () => world.TickRender(worldRenderer));
 				}
 
-				if (benchmark != null)
-					benchmark.Tick(LocalTick);
+				benchmark?.Tick(LocalTick);
 			}
 		}
 
@@ -836,12 +827,10 @@ namespace OpenRA
 			finally
 			{
 				// Ensure that the active replay is properly saved
-				if (OrderManager != null)
-					OrderManager.Dispose();
+				OrderManager?.Dispose();
 			}
 
-			if (worldRenderer != null)
-				worldRenderer.Dispose();
+			worldRenderer?.Dispose();
 			ModData.Dispose();
 			ChromeProvider.Deinitialize();
 
@@ -880,8 +869,7 @@ namespace OpenRA
 
 		public static void Disconnect()
 		{
-			if (OrderManager.World != null)
-				OrderManager.World.TraitDict.PrintReport();
+			OrderManager.World?.TraitDict.PrintReport();
 
 			OrderManager.Dispose();
 			CloseServer();
@@ -890,8 +878,7 @@ namespace OpenRA
 
 		public static void CloseServer()
 		{
-			if (server != null)
-				server.Shutdown();
+			server?.Shutdown();
 		}
 
 		public static T CreateObject<T>(string name)

OpenRA.Game/Graphics/Animation.cs

@@ -156,7 +156,7 @@ namespace OpenRA.Graphics
 				{
 					frame = CurrentSequence.Length - 1;
 					tickFunc = () => { };
-					if (after != null) after();
+					after?.Invoke();
 				}
 			};
 		}

OpenRA.Game/Graphics/Sheet.cs

@@ -146,8 +146,7 @@ namespace OpenRA.Graphics
 
 		public void Dispose()
 		{
-			if (texture != null)
-				texture.Dispose();
+			texture?.Dispose();
 		}
 	}
 }

OpenRA.Game/Graphics/WorldRenderer.cs

@@ -97,8 +97,8 @@ namespace OpenRA.Graphics
 				var oldHeight = palette.Height;
 				palette.AddPalette(name, pal, allowModifiers);
 
-				if (oldHeight != palette.Height && PaletteInvalidated != null)
-					PaletteInvalidated();
+				if (oldHeight != palette.Height)
+					PaletteInvalidated?.Invoke();
 			}
 		}
 
@@ -258,8 +258,7 @@ namespace OpenRA.Graphics
 			if (enableDepthBuffer)
 				Game.Renderer.Context.EnableDepthBuffer();
 
-			if (terrainRenderer != null)
-				terrainRenderer.RenderTerrain(this, Viewport);
+			terrainRenderer?.RenderTerrain(this, Viewport);
 
 			Game.Renderer.Flush();
 

OpenRA.Game/InstalledMods.cs

@@ -78,8 +78,7 @@ namespace OpenRA
 				Log.Write("debug", "Load mod '{0}': {1}".F(path, e));
 			}
 
-			if (package != null)
-				package.Dispose();
+			package?.Dispose();
 
 			return null;
 		}

OpenRA.Game/LocalPlayerProfile.cs

@@ -108,8 +108,7 @@ namespace OpenRA
 				}
 				finally
 				{
-					if (onComplete != null)
-						onComplete();
+					onComplete?.Invoke();
 				}
 			};
 

OpenRA.Game/Manifest.cs

@@ -245,8 +245,7 @@ namespace OpenRA
 			foreach (var module in modules)
 			{
 				var disposableModule = module as IDisposable;
-				if (disposableModule != null)
-					disposableModule.Dispose();
+				disposableModule?.Dispose();
 			}
 		}
 	}

OpenRA.Game/Map/CellLayer.cs

@@ -73,8 +73,7 @@ namespace OpenRA
 			{
 				entries[Index(cell)] = value;
 
-				if (CellEntryChanged != null)
-					CellEntryChanged(cell);
+				CellEntryChanged?.Invoke(cell);
 			}
 		}
 
@@ -90,8 +89,7 @@ namespace OpenRA
 			{
 				entries[Index(uv)] = value;
 
-				if (CellEntryChanged != null)
-					CellEntryChanged(uv.ToCPos(GridType));
+				CellEntryChanged?.Invoke(uv.ToCPos(GridType));
 			}
 		}
 

OpenRA.Game/Map/MapCache.cs

@@ -111,8 +111,7 @@ namespace OpenRA
 					}
 					catch (Exception e)
 					{
-						if (mapPackage != null)
-							mapPackage.Dispose();
+						mapPackage?.Dispose();
 						Console.WriteLine("Failed to load map: {0}", map);
 						Console.WriteLine("Details: {0}", e);
 						Log.Write("debug", "Failed to load map: {0}", map);
@@ -192,8 +191,7 @@ namespace OpenRA
 					foreach (var p in maps.Values)
 						p.UpdateRemoteSearch(MapStatus.Unavailable, null);
 
-					if (queryFailed != null)
-						queryFailed();
+					queryFailed?.Invoke();
 
 					return;
 				}
@@ -213,8 +211,7 @@ namespace OpenRA
 				{
 					Log.Write("debug", "Can't parse remote map search data:\n{0}", data);
 					Log.Write("debug", "Exception: {0}", e);
-					if (queryFailed != null)
-						queryFailed();
+					queryFailed?.Invoke();
 				}
 			};
 
@@ -298,8 +295,7 @@ namespace OpenRA
 				Game.RunAfterTick(() =>
 				{
 					// Wait for any existing thread to exit before starting a new one.
-					if (previewLoaderThread != null)
-						previewLoaderThread.Join();
+					previewLoaderThread?.Join();
 
 					previewLoaderThread = new Thread(LoadAsyncInternal)
 					{

OpenRA.Game/Map/MapPreview.cs

@@ -412,8 +412,7 @@ namespace OpenRA
 				if (innerData.Preview != null)
 					cache.CacheMinimap(this);
 
-				if (parseMetadata != null)
-					parseMetadata(this);
+				parseMetadata?.Invoke(this);
 			}
 
 			// Update the status and class unconditionally
@@ -522,9 +521,7 @@ namespace OpenRA
 		public void Delete()
 		{
 			Invalidate();
-			var deleteFromPackage = parentPackage as IReadWritePackage;
-			if (deleteFromPackage != null)
-				deleteFromPackage.Delete(Package.Name);
+			(parentPackage as IReadWritePackage)?.Delete(Package.Name);
 		}
 
 		Stream IReadOnlyFileSystem.Open(string filename)

OpenRA.Game/ModData.cs

@@ -177,8 +177,7 @@ namespace OpenRA
 
 		public Map PrepareMap(string uid)
 		{
-			if (LoadScreen != null)
-				LoadScreen.Display();
+			LoadScreen?.Display();
 
 			if (MapCache[uid].Status != MapStatus.Available)
 				throw new InvalidDataException("Invalid map uid: {0}".F(uid));
@@ -202,12 +201,10 @@ namespace OpenRA
 
 		public void Dispose()
 		{
-			if (LoadScreen != null)
-				LoadScreen.Dispose();
+			LoadScreen?.Dispose();
 			MapCache.Dispose();
 
-			if (ObjectCreator != null)
-				ObjectCreator.Dispose();
+			ObjectCreator?.Dispose();
 
 			Manifest.Dispose();
 		}

OpenRA.Game/Network/Connection.cs

@@ -174,23 +174,21 @@ namespace OpenRA.Network
 			foreach (var p in packets)
 			{
 				packetFn(p.FromClient, p.Data);
-				if (Recorder != null)
-					Recorder.Receive(p.FromClient, p.Data);
+				Recorder?.Receive(p.FromClient, p.Data);
 			}
 		}
 
 		public void StartRecording(Func<string> chooseFilename)
 		{
 			// If we have a previous recording then save/dispose it and start a new one.
-			if (Recorder != null)
-				Recorder.Dispose();
+			Recorder?.Dispose();
 			Recorder = new ReplayRecorder(chooseFilename);
 		}
 
 		protected virtual void Dispose(bool disposing)
 		{
-			if (disposing && Recorder != null)
-				Recorder.Dispose();
+			if (disposing)
+				Recorder?.Dispose();
 		}
 
 		public void Dispose()
@@ -372,8 +370,7 @@ namespace OpenRA.Network
 
 			// Closing the stream will cause any reads on the receiving thread to throw.
 			// This will mark the connection as no longer connected and the thread will terminate cleanly.
-			if (tcp != null)
-				tcp.Close();
+			tcp?.Close();
 
 			base.Dispose(disposing);
 		}

OpenRA.Game/Network/OrderManager.cs

@@ -206,8 +206,7 @@ namespace OpenRA.Network
 		public void Dispose()
 		{
 			disposed = true;
-			if (Connection != null)
-				Connection.Dispose();
+			Connection?.Dispose();
 		}
 	}
 

OpenRA.Game/Network/ReplayRecorder.cs

@@ -100,8 +100,7 @@ namespace OpenRA.Network
 				Metadata.Write(writer);
 			}
 
-			if (preStartBuffer != null)
-				preStartBuffer.Dispose();
+			preStartBuffer?.Dispose();
 			writer.Close();
 		}
 	}

OpenRA.Game/Network/UnitOrders.cs

@@ -145,8 +145,7 @@ namespace OpenRA.Network
 						var data = MiniYaml.FromString(order.TargetString)[0];
 						var traitIndex = int.Parse(data.Key);
 
-						if (world != null)
-							world.AddGameSaveTraitData(traitIndex, data.Value);
+						world?.AddGameSaveTraitData(traitIndex, data.Value);
 
 						break;
 					}

OpenRA.Game/ObjectCreator.cs

@@ -67,10 +67,7 @@ namespace OpenRA
 				if (a.FullName == e.Name)
 					return a;
 
-			if (assemblies == null)
-				return null;
-
-			return assemblies.Select(a => a.Assembly).FirstOrDefault(a => a.FullName == e.Name);
+			return assemblies?.Select(a => a.Assembly).FirstOrDefault(a => a.FullName == e.Name);
 		}
 
 		// Only used by the linter to prevent exceptions from being thrown during a lint run

OpenRA.Game/Renderer.cs

@@ -115,8 +115,7 @@ namespace OpenRA
 					font.Dispose();
 			using (new PerfTimer("SpriteFonts"))
 			{
-				if (fontSheetBuilder != null)
-					fontSheetBuilder.Dispose();
+				fontSheetBuilder?.Dispose();
 				fontSheetBuilder = new SheetBuilder(SheetType.BGRA, 512);
 				Fonts = modData.Manifest.Get<Fonts>().FontList.ToDictionary(x => x.Key,
 					x => new SpriteFont(x.Value.Font, modData.DefaultFileSystem.Open(x.Value.Font).ReadAllBytes(),
@@ -156,8 +155,7 @@ namespace OpenRA
 
 			if (screenSprite == null || screenSprite.Sheet.Size != surfaceBufferSize)
 			{
-				if (screenBuffer != null)
-					screenBuffer.Dispose();
+				screenBuffer?.Dispose();
 
 				// Render the screen into a frame buffer to simplify reading back screenshots
 				screenBuffer = Context.CreateFrameBuffer(surfaceBufferSize, Color.FromArgb(0xFF, 0, 0, 0));
@@ -195,8 +193,7 @@ namespace OpenRA
 			var worldBufferSize = worldViewport.Size.NextPowerOf2();
 			if (worldSprite == null || worldSprite.Sheet.Size != worldBufferSize)
 			{
-				if (worldBuffer != null)
-					worldBuffer.Dispose();
+				worldBuffer?.Dispose();
 
 				// Render the world into a framebuffer at 1:1 scaling to allow the depth buffer to match the artwork at all zoom levels
 				worldBuffer = Context.CreateFrameBuffer(worldBufferSize);
@@ -329,8 +326,7 @@ namespace OpenRA
 			{
 				if (currentBatchRenderer == value)
 					return;
-				if (currentBatchRenderer != null)
-					currentBatchRenderer.Flush();
+				currentBatchRenderer?.Flush();
 				currentBatchRenderer = value;
 			}
 		}
@@ -460,8 +456,7 @@ namespace OpenRA
 		{
 			WorldModelRenderer.Dispose();
 			tempBuffer.Dispose();
-			if (fontSheetBuilder != null)
-				fontSheetBuilder.Dispose();
+			fontSheetBuilder?.Dispose();
 			if (Fonts != null)
 				foreach (var font in Fonts.Values)
 					font.Dispose();

OpenRA.Game/Scripting/ScriptContext.cs

@@ -267,8 +267,7 @@ namespace OpenRA.Scripting
 				return;
 
 			disposed = true;
-			if (runtime != null)
-				runtime.Dispose();
+			runtime?.Dispose();
 		}
 
 		static IEnumerable<Type> ExtractRequiredTypes(Type t)

OpenRA.Game/Scripting/ScriptTypes.cs

@@ -168,8 +168,7 @@ namespace OpenRA.Scripting
 			{
 				// Object needs additional notification / context
 				var notify = obj as IScriptNotifyBind;
-				if (notify != null)
-					notify.OnScriptBind(context);
+				notify?.OnScriptBind(context);
 
 				return new LuaCustomClrObject(obj);
 			}

OpenRA.Game/Server/Server.cs

@@ -244,8 +244,7 @@ namespace OpenRA.Server
 						}
 
 						var conn = Conns.SingleOrDefault(c => c.Socket == s);
-						if (conn != null)
-							conn.ReadData(this);
+						conn?.ReadData(this);
 					}
 
 					delayedActions.PerformActions(0);

OpenRA.Game/Sound/Sound.cs

@@ -88,8 +88,7 @@ namespace OpenRA
 
 			if (sounds != null)
 				foreach (var soundSource in sounds.Values)
-					if (soundSource != null)
-						soundSource.Dispose();
+					soundSource?.Dispose();
 
 			this.loaders = loaders;
 			this.fileSystem = fileSystem;
@@ -430,8 +429,8 @@ namespace OpenRA
 			StopAudio();
 			if (sounds != null)
 				foreach (var soundSource in sounds.Values)
-					if (soundSource != null)
-						soundSource.Dispose();
+					soundSource?.Dispose();
+
 			soundEngine.Dispose();
 		}
 	}

OpenRA.Game/Widgets/Widget.cs

@@ -113,11 +113,9 @@ namespace OpenRA.Widgets
 
 			if (wasMouseOver != MouseOverWidget)
 			{
-				if (wasMouseOver != null)
-					wasMouseOver.MouseExited();
+				wasMouseOver?.MouseExited();
 
-				if (MouseOverWidget != null)
-					MouseOverWidget.MouseEntered();
+				MouseOverWidget?.MouseEntered();
 			}
 
 			return handled;

OpenRA.Game/Widgets/WidgetLoader.cs

@@ -50,8 +50,7 @@ namespace OpenRA
 
 			var widget = NewWidget(node.Key, args);
 
-			if (parent != null)
-				parent.AddChild(widget);
+			parent?.AddChild(widget);
 
 			if (node.Key.Contains("@"))
 				FieldLoader.LoadField(widget, "Id", node.Key.Split('@')[1]);

OpenRA.Game/World.cs

@@ -89,8 +89,7 @@ namespace OpenRA
 				{
 					renderPlayer = value;
 
-					if (RenderPlayerChanged != null)
-						RenderPlayerChanged(value);
+					RenderPlayerChanged?.Invoke(value);
 				}
 			}
 		}
@@ -159,8 +158,7 @@ namespace OpenRA
 			set
 			{
 				Sync.AssertUnsynced("The current order generator may not be changed from synced code");
-				if (orderGenerator != null)
-					orderGenerator.Deactivate();
+				orderGenerator?.Deactivate();
 
 				orderGenerator = value;
 			}
@@ -581,8 +579,7 @@ namespace OpenRA
 		{
 			Disposing = true;
 
-			if (OrderGenerator != null)
-				OrderGenerator.Deactivate();
+			OrderGenerator?.Deactivate();
 
 			frameEndActions.Clear();
 

OpenRA.Mods.Cnc/Activities/Infiltrate.cs

@@ -65,8 +65,7 @@ namespace OpenRA.Mods.Cnc.Activities
 				t.Infiltrated(targetActor, self, infiltrates.Info.Types);
 
 			var exp = self.Owner.PlayerActor.TraitOrDefault<PlayerExperience>();
-			if (exp != null)
-				exp.GiveExperience(infiltrates.Info.PlayerExperience);
+			exp?.GiveExperience(infiltrates.Info.PlayerExperience);
 
 			if (!string.IsNullOrEmpty(infiltrates.Info.Notification))
 				Game.Sound.PlayNotification(self.World.Map.Rules, self.Owner, "Speech",

OpenRA.Mods.Cnc/Activities/Teleport.cs

@@ -97,8 +97,8 @@ namespace OpenRA.Mods.Cnc.Activities
 			}
 
 			// Consume teleport charges if this wasn't triggered via chronosphere
-			if (teleporter == self && pc != null)
-				pc.ResetChargeTime();
+			if (teleporter == self)
+				pc?.ResetChargeTime();
 
 			// Trigger screen desaturate effect
 			if (screenFlash)

OpenRA.Mods.Cnc/Graphics/VoxelLoader.cs

@@ -194,8 +194,7 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 		public void RefreshBuffer()
 		{
-			if (vertexBuffer != null)
-				vertexBuffer.Dispose();
+			vertexBuffer?.Dispose();
 			vertexBuffer = Game.Renderer.CreateVertexBuffer(totalVertexCount);
 			vertexBuffer.SetData(vertices.SelectMany(v => v).ToArray(), totalVertexCount);
 			cachedVertexCount = totalVertexCount;
@@ -234,8 +233,7 @@ namespace OpenRA.Mods.Cnc.Graphics
 
 		public void Dispose()
 		{
-			if (vertexBuffer != null)
-				vertexBuffer.Dispose();
+			vertexBuffer?.Dispose();
 			sheetBuilder.Dispose();
 		}
 	}

OpenRA.Mods.Cnc/Traits/DrainPrerequisitePowerOnDamage.cs

@@ -52,13 +52,8 @@ namespace OpenRA.Mods.Cnc.Traits
 			if (!IsTraitDisabled && damage != null)
 			{
 				var damageSubTicks = (int)(damage.Value * 100L * Info.DamageMultiplier / Info.DamageDivisor);
-
 				if (spm.Powers.TryGetValue(Info.OrderName, out var spi))
-				{
-					var dspi = spi as GrantPrerequisiteChargeDrainPower.DischargeableSupportPowerInstance;
-					if (dspi != null)
-						dspi.Discharge(damageSubTicks);
-				}
+					(spi as GrantPrerequisiteChargeDrainPower.DischargeableSupportPowerInstance)?.Discharge(damageSubTicks);
 			}
 
 			return 100;

OpenRA.Mods.Cnc/Traits/MadTank.cs

@@ -240,9 +240,7 @@ namespace OpenRA.Mods.Cnc.Traits
 					new LocationInit(self.Location),
 					new OwnerInit(self.Owner)
 				});
-				var driverMobile = driver.TraitOrDefault<Mobile>();
-				if (driverMobile != null)
-					driverMobile.Nudge(driver);
+				driver.TraitOrDefault<Mobile>()?.Nudge(driver);
 			}
 		}
 	}

OpenRA.Mods.Cnc/Traits/TransferTimedExternalConditionOnTransform.cs

@@ -49,8 +49,7 @@ namespace OpenRA.Mods.Cnc.Traits
 			var external = toActor.TraitsImplementing<ExternalCondition>()
 				.FirstOrDefault(t => t.Info.Condition == info.Condition && t.CanGrantCondition(toActor, this));
 
-			if (external != null)
-				external.GrantCondition(toActor, this, duration, remaining);
+			external?.GrantCondition(toActor, this, duration, remaining);
 		}
 
 		void IConditionTimerWatcher.Update(int duration, int remaining)

OpenRA.Mods.Common/Activities/Air/FlyAttack.cs

@@ -128,8 +128,8 @@ namespace OpenRA.Mods.Common.Activities
 					return true;
 
 				// AbortOnResupply cancels the current activity (after resupplying) plus any queued activities
-				if (attackAircraft.Info.AbortOnResupply && NextActivity != null)
-					NextActivity.Cancel(self);
+				if (attackAircraft.Info.AbortOnResupply)
+					NextActivity?.Cancel(self);
 
 				QueueChild(new ReturnToBase(self));
 				returnToBase = true;

OpenRA.Mods.Common/Activities/CaptureActor.cs

@@ -112,11 +112,7 @@ namespace OpenRA.Mods.Common.Activities
 					t.OnCapture(enterActor, self, oldOwner, self.Owner, captures.Info.CaptureTypes);
 
 				if (self.Owner.Stances[oldOwner].HasStance(captures.Info.PlayerExperienceStances))
-				{
-					var exp = self.Owner.PlayerActor.TraitOrDefault<PlayerExperience>();
-					if (exp != null)
-						exp.GiveExperience(captures.Info.PlayerExperience);
-				}
+					self.Owner.PlayerActor.TraitOrDefault<PlayerExperience>()?.GiveExperience(captures.Info.PlayerExperience);
 
 				if (captures.Info.ConsumedByCapture)
 					self.Dispose();

OpenRA.Mods.Common/Activities/Move/Move.cs

@@ -177,8 +177,7 @@ namespace OpenRA.Mods.Common.Activities
 
 			if (IsCanceling && mobile.CanStayInCell(mobile.ToCell))
 			{
-				if (path != null)
-					path.Clear();
+				path?.Clear();
 
 				return true;
 			}

OpenRA.Mods.Common/Activities/Resupply.cs

@@ -138,9 +138,7 @@ namespace OpenRA.Mods.Common.Activities
 					QueueChild(move.MoveTo(targetCell, targetLineColor: Color.Green));
 
 				var delta = (self.CenterPosition - host.CenterPosition).LengthSquared;
-				var transport = transportCallers.FirstOrDefault(t => t.MinimumDistance.LengthSquared < delta);
-				if (transport != null)
-					transport.RequestTransport(self, targetCell);
+				transportCallers.FirstOrDefault(t => t.MinimumDistance.LengthSquared < delta)?.RequestTransport(self, targetCell);
 
 				return false;
 			}
@@ -261,11 +259,7 @@ namespace OpenRA.Mods.Common.Activities
 			if (health.DamageState == DamageState.Undamaged)
 			{
 				if (host.Actor.Owner != self.Owner)
-				{
-					var exp = host.Actor.Owner.PlayerActor.TraitOrDefault<PlayerExperience>();
-					if (exp != null)
-						exp.GiveExperience(repairsUnits.Info.PlayerExperience);
-				}
+					host.Actor.Owner.PlayerActor.TraitOrDefault<PlayerExperience>()?.GiveExperience(repairsUnits.Info.PlayerExperience);
 
 				Game.Sound.PlayNotification(self.World.Map.Rules, self.Owner, "Speech", repairsUnits.Info.FinishRepairingNotification, self.Owner.Faction.InternalName);
 

OpenRA.Mods.Common/ColorValidator.cs

@@ -60,8 +60,7 @@ namespace OpenRA.Mods.Common
 			askedColor.ToAhsv(out _, out _, out var s, out var v);
 			if (s < HsvSaturationRange[0] || s > HsvSaturationRange[1] || v < HsvValueRange[0] || v > HsvValueRange[1])
 			{
-				if (errorMessages != null)
-					errorMessages.Add("Color was adjusted to be inside the allowed range.");
+				errorMessages?.Add("Color was adjusted to be inside the allowed range.");
 				forbiddenColor = askedColor;
 				return false;
 			}
@@ -69,16 +68,14 @@ namespace OpenRA.Mods.Common
 			// Validate color against the current map tileset
 			if (!IsValid(askedColor, terrainColors, out forbiddenColor))
 			{
-				if (errorMessages != null)
-					errorMessages.Add("Color was adjusted to be less similar to the terrain.");
+				errorMessages?.Add("Color was adjusted to be less similar to the terrain.");
 				return false;
 			}
 
 			// Validate color against other clients
 			if (!IsValid(askedColor, playerColors, out forbiddenColor))
 			{
-				if (errorMessages != null)
-					errorMessages.Add("Color was adjusted to be less similar to another player.");
+				errorMessages?.Add("Color was adjusted to be less similar to another player.");
 				return false;
 			}
 

OpenRA.Mods.Common/DiscordService.cs

@@ -178,37 +178,27 @@ namespace OpenRA.Mods.Common
 
 		public static void UpdateStatus(DiscordState state, string details = null, string secret = null, int? players = null, int? slots = null)
 		{
-			var service = GetService();
-			if (service != null)
-				service.SetStatus(state, details, secret, players, slots);
+			GetService()?.SetStatus(state, details, secret, players, slots);
 		}
 
 		public static void SetPlayers(int players, int slots)
 		{
-			var service = GetService();
-			if (service != null)
+			GetService()?.client.UpdateParty(new Party
 			{
-				service.client.UpdateParty(new Party
-				{
-					ID = Secrets.CreateFriendlySecret(new Random()),
-					Size = players,
-					Max = slots
-				});
-			}
+				ID = Secrets.CreateFriendlySecret(new Random()),
+				Size = players,
+				Max = slots
+			});
 		}
 
 		public static void UpdatePlayers(int players, int slots)
 		{
-			var service = GetService();
-			if (service != null)
-				service.client.UpdatePartySize(players, slots);
+			GetService()?.client.UpdatePartySize(players, slots);
 		}
 
 		public static void UpdateDetails(string details)
 		{
-			var service = GetService();
-			if (service != null)
-				service.client.UpdateDetails(details);
+			GetService()?.client.UpdateDetails(details);
 		}
 	}
 }

OpenRA.Mods.Common/Effects/Beacon.cs

@@ -96,17 +96,10 @@ namespace OpenRA.Mods.Common.Effects
 				arrowSpeed *= -1;
 			}
 
-			if (arrow != null)
-				arrow.Tick();
-
-			if (beacon != null)
-				beacon.Tick();
-
-			if (circles != null)
-				circles.Tick();
-
-			if (clock != null)
-				clock.Tick();
+			arrow?.Tick();
+			beacon?.Tick();
+			circles?.Tick();
+			clock?.Tick();
 
 			if (duration > 0 && duration <= tick++)
 				owner.World.AddFrameEndTask(w => w.Remove(this));

OpenRA.Mods.Common/Effects/RallyPointIndicator.cs

@@ -48,18 +48,15 @@ namespace OpenRA.Mods.Common.Effects
 
 		void IEffect.Tick(World world)
 		{
-			if (flag != null)
-				flag.Tick();
+			flag?.Tick();
 
-			if (circles != null)
-				circles.Tick();
+			circles?.Tick();
 
 			if (cachedLocations == null || !cachedLocations.SequenceEqual(rp.Path))
 			{
 				UpdateTargetLineNodes(world);
 
-				if (circles != null)
-					circles.Play(rp.Info.CirclesSequence);
+				circles?.Play(rp.Info.CirclesSequence);
 			}
 
 			if (!building.IsInWorld || building.IsDead)

OpenRA.Mods.Common/FileFormats/Blast.cs

@@ -107,8 +107,7 @@ namespace OpenRA.Mods.Common.FileFormats
 						for (var i = 0; i < next; i++)
 							output.WriteByte(outBuffer[i]);
 
-						if (onProgress != null)
-							onProgress(input.Position - inputStart, output.Position - outputStart);
+						onProgress?.Invoke(input.Position - inputStart, output.Position - outputStart);
 						break;
 					}
 
@@ -155,8 +154,7 @@ namespace OpenRA.Mods.Common.FileFormats
 							next = 0;
 							first = false;
 
-							if (onProgress != null)
-								onProgress(input.Position - inputStart, output.Position - outputStart);
+							onProgress?.Invoke(input.Position - inputStart, output.Position - outputStart);
 						}
 					}
 					while (len != 0);
@@ -173,8 +171,7 @@ namespace OpenRA.Mods.Common.FileFormats
 						next = 0;
 						first = false;
 
-						if (onProgress != null)
-							onProgress(input.Position - inputStart, output.Position - outputStart);
+						onProgress?.Invoke(input.Position - inputStart, output.Position - outputStart);
 					}
 				}
 			}

OpenRA.Mods.Common/FileFormats/InstallShieldCABCompression.cs

@@ -243,8 +243,7 @@ namespace OpenRA.Mods.Common.FileFormats
 						toExtract -= bytesToExtract;
 						while (!inf.IsNeedingInput)
 						{
-							if (onProgress != null)
-								onProgress((int)(100 * output.Position / file.ExpandedSize));
+							onProgress?.Invoke((int)(100 * output.Position / file.ExpandedSize));
 
 							var inflated = inf.Inflate(buffer);
 							output.Write(buffer, 0, inflated);
@@ -258,8 +257,7 @@ namespace OpenRA.Mods.Common.FileFormats
 				{
 					do
 					{
-						if (onProgress != null)
-							onProgress((int)(100 * output.Position / file.ExpandedSize));
+						onProgress?.Invoke((int)(100 * output.Position / file.ExpandedSize));
 
 						toExtract -= remainingInArchive;
 						output.Write(GetBytes(remainingInArchive), 0, (int)remainingInArchive);

OpenRA.Mods.Common/FileFormats/MSCabCompression.cs

@@ -101,8 +101,7 @@ namespace OpenRA.Mods.Common.FileFormats
 			var decompressedBytes = 0;
 			for (var i = 0; i < folder.BlockCount; i++)
 			{
-				if (onProgress != null)
-					onProgress((int)(100 * output.Position / file.DecompressedLength));
+				onProgress?.Invoke((int)(100 * output.Position / file.DecompressedLength));
 
 				// Ignore checksums
 				stream.Position += 4;

OpenRA.Mods.Common/LoadScreens/SheetLoadScreen.cs

@@ -52,8 +52,7 @@ namespace OpenRA.Mods.Common.LoadScreens
 				dpiScale = scale;
 
 				// Force images to be reloaded on the next display
-				if (sheet != null)
-					sheet.Dispose();
+				sheet?.Dispose();
 
 				sheet = null;
 			}
@@ -94,8 +93,8 @@ namespace OpenRA.Mods.Common.LoadScreens
 
 		protected override void Dispose(bool disposing)
 		{
-			if (disposing && sheet != null)
-				sheet.Dispose();
+			if (disposing)
+				sheet?.Dispose();
 
 			base.Dispose(disposing);
 		}

OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs

@@ -218,8 +218,7 @@ namespace OpenRA.Mods.Common.Orders
 				world.CancelInputMode();
 
 			foreach (var v in variants)
-				if (v.Preview != null)
-					v.Preview.Tick();
+				v.Preview?.Tick();
 		}
 
 		void IOrderGenerator.SelectionChanged(World world, IEnumerable<Actor> selected) { }

OpenRA.Mods.Common/Projectiles/Bullet.cs

@@ -197,8 +197,7 @@ namespace OpenRA.Mods.Common.Projectiles
 
 		public void Tick(World world)
 		{
-			if (anim != null)
-				anim.Tick();
+			anim?.Tick();
 
 			lastPos = pos;
 			pos = WPos.LerpQuadratic(source, target, angle, ticks, length);

OpenRA.Mods.Common/Projectiles/GravityBomb.cs

@@ -100,8 +100,7 @@ namespace OpenRA.Mods.Common.Projectiles
 				args.Weapon.Impact(Target.FromPos(pos), warheadArgs);
 			}
 
-			if (anim != null)
-				anim.Tick();
+			anim?.Tick();
 		}
 
 		public IEnumerable<IRenderable> Render(WorldRenderer wr)

OpenRA.Mods.Common/Projectiles/Missile.cs

@@ -792,8 +792,7 @@ namespace OpenRA.Mods.Common.Projectiles
 		public void Tick(World world)
 		{
 			ticks++;
-			if (anim != null)
-				anim.Tick();
+			anim?.Tick();
 
 			// Switch from freefall mode to homing mode
 			if (ticks == info.HomingActivationDelay + 1)

OpenRA.Mods.Common/Projectiles/Railgun.cs

@@ -227,8 +227,7 @@ namespace OpenRA.Mods.Common.Projectiles
 				}
 			}
 
-			if (hitanim != null)
-				hitanim.Tick();
+			hitanim?.Tick();
 
 			if (ticks++ > info.Duration && animationComplete)
 				world.AddFrameEndTask(w => w.Remove(this));

OpenRA.Mods.Common/Scripting/CallLuaFunc.cs

@@ -31,8 +31,7 @@ namespace OpenRA.Mods.Common.Activities
 		{
 			try
 			{
-				if (function != null)
-					function.Call().Dispose();
+				function?.Call().Dispose();
 			}
 			catch (Exception ex)
 			{

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

@@ -29,14 +29,7 @@ namespace OpenRA.Mods.Common.Scripting
 		[Desc("Creates a new radar ping that stays for the specified time at the specified WPos.")]
 		public void Ping(Player player, WPos position, Color color, int duration = 30 * 25)
 		{
-			if (radarPings != null)
-			{
-				radarPings.Add(
-					() => player.World.RenderPlayer == player,
-					position,
-					color,
-					duration);
-			}
+			radarPings?.Add(() => player.World.RenderPlayer == player, position, color, duration);
 		}
 	}
 }

OpenRA.Mods.Common/Scripting/LuaScript.cs

@@ -54,8 +54,7 @@ namespace OpenRA.Mods.Common.Scripting
 			if (disposed)
 				return;
 
-			if (context != null)
-				context.Dispose();
+			context?.Dispose();
 
 			disposed = true;
 		}

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

@@ -172,10 +172,7 @@ namespace OpenRA.Mods.Common.Scripting
 		{
 			get
 			{
-				if (autotarget == null)
-					return null;
-
-				return autotarget.Stance.ToString();
+				return autotarget?.Stance.ToString();
 			}
 
 			set
@@ -197,10 +194,8 @@ namespace OpenRA.Mods.Common.Scripting
 			get
 			{
 				var tooltip = tooltips.FirstEnabledTraitOrDefault();
-				if (tooltip == null)
-					return null;
 
-				return tooltip.Info.Name;
+				return tooltip?.Info.Name;
 			}
 		}
 

OpenRA.Mods.Common/ServerTraits/MasterServerPinger.cs

@@ -98,8 +98,7 @@ namespace OpenRA.Mods.Common.Server
 
 		public void GameEnded(S server)
 		{
-			if (LanGameBeacon != null)
-				LanGameBeacon.Stop();
+			LanGameBeacon?.Stop();
 
 			lastChanged = Game.RunTime;
 		}

OpenRA.Mods.Common/Traits/BotModules/Squads/StateMachine.cs

@@ -18,8 +18,7 @@ namespace OpenRA.Mods.Common.Traits.BotModules.Squads
 
 		public void Update(Squad squad)
 		{
-			if (currentState != null)
-				currentState.Tick(squad);
+			currentState?.Tick(squad);
 		}
 
 		public void ChangeState(Squad squad, IState newState, bool rememberPrevious)
@@ -27,14 +26,12 @@ namespace OpenRA.Mods.Common.Traits.BotModules.Squads
 			if (rememberPrevious)
 				previousState = currentState;
 
-			if (currentState != null)
-				currentState.Deactivate(squad);
+			currentState?.Deactivate(squad);
 
 			if (newState != null)
 				currentState = newState;
 
-			if (currentState != null)
-				currentState.Activate(squad);
+			currentState?.Activate(squad);
 		}
 
 		public void RevertToPreviousState(Squad squad, bool saveCurrentState)

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

@@ -302,8 +302,7 @@ namespace OpenRA.Mods.Common.Traits
 			// If this bridge repair operation connects two pathfinding domains,
 			// update the domain index.
 			var domainIndex = self.World.WorldActor.TraitOrDefault<DomainIndex>();
-			if (domainIndex != null)
-				domainIndex.UpdateCells(self.World, footprint.Keys);
+			domainIndex?.UpdateCells(self.World, footprint.Keys);
 
 			if (LongBridgeSegmentIsDead() && !killedUnits)
 			{

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

@@ -70,9 +70,7 @@ namespace OpenRA.Mods.Common.Traits
 			foreach (var cell in cells)
 				self.World.Map.CustomTerrain[cell] = terrainIndex;
 
-			var domainIndex = self.World.WorldActor.TraitOrDefault<DomainIndex>();
-			if (domainIndex != null)
-				domainIndex.UpdateCells(self.World, cells);
+			self.World.WorldActor.TraitOrDefault<DomainIndex>()?.UpdateCells(self.World, cells);
 		}
 
 		void INotifyAddedToWorld.AddedToWorld(Actor self)

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

@@ -91,10 +91,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		void INotifyLineBuildSegmentsChanged.SegmentRemoved(Actor self, Actor segment)
 		{
-			if (segments == null)
-				return;
-
-			segments.Remove(segment);
+			segments?.Remove(segment);
 		}
 
 		void INotifyAddedToWorld.AddedToWorld(Actor self)

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

@@ -172,9 +172,7 @@ namespace OpenRA.Mods.Common.Traits
 						if (r == self.Owner)
 							return;
 
-						var exp = r.PlayerActor.TraitOrDefault<PlayerExperience>();
-						if (exp != null)
-							exp.GiveExperience(Info.PlayerExperience);
+						r.PlayerActor.TraitOrDefault<PlayerExperience>()?.GiveExperience(Info.PlayerExperience);
 					});
 
 					Repairers.Clear();

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

@@ -131,8 +131,8 @@ namespace OpenRA.Mods.Common.Traits
 
 			// Manually manage the inner activity queue
 			var activity = currentTransform ?? transform.GetTransformActivity(self);
-			if (!order.Queued && activity.NextActivity != null)
-				activity.NextActivity.Cancel(self);
+			if (!order.Queued)
+				activity.NextActivity?.Cancel(self);
 
 			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target, Color.Green));
 

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

@@ -95,8 +95,8 @@ namespace OpenRA.Mods.Common.Traits
 
 			// Manually manage the inner activity queue
 			var activity = currentTransform ?? transform.GetTransformActivity(self);
-			if (!order.Queued && activity.NextActivity != null)
-				activity.NextActivity.Cancel(self);
+			if (!order.Queued)
+				activity.NextActivity?.Cancel(self);
 
 			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target, Color.Green));
 

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

@@ -110,8 +110,8 @@ namespace OpenRA.Mods.Common.Traits
 
 				// Manually manage the inner activity queue
 				var activity = currentTransform ?? transform.GetTransformActivity(self);
-				if (!order.Queued && activity.NextActivity != null)
-					activity.NextActivity.Cancel(self);
+				if (!order.Queued)
+					activity.NextActivity?.Cancel(self);
 
 				activity.Queue(new IssueOrderAfterTransform("Move", order.Target, Color.Green));
 

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

@@ -129,8 +129,8 @@ namespace OpenRA.Mods.Common.Traits
 
 			// Manually manage the inner activity queue
 			var activity = currentTransform ?? transform.GetTransformActivity(self);
-			if (!order.Queued && activity.NextActivity != null)
-				activity.NextActivity.Cancel(self);
+			if (!order.Queued)
+				activity.NextActivity?.Cancel(self);
 
 			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target, Color.Green));
 

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

@@ -123,8 +123,8 @@ namespace OpenRA.Mods.Common.Traits
 
 			// Manually manage the inner activity queue
 			var activity = currentTransform ?? transform.GetTransformActivity(self);
-			if (!order.Queued && activity.NextActivity != null)
-				activity.NextActivity.Cancel(self);
+			if (!order.Queued)
+				activity.NextActivity?.Cancel(self);
 
 			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target, Color.Green));
 

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

@@ -41,8 +41,8 @@ namespace OpenRA.Mods.Common.Traits
 			if (!order.Queued || currentTransform == null)
 				return;
 
-			if (!order.Queued && currentTransform.NextActivity != null)
-				currentTransform.NextActivity.Cancel(self);
+			if (!order.Queued)
+				currentTransform.NextActivity?.Cancel(self);
 
 			currentTransform.Queue(new IssueOrderAfterTransform("DeployTransform", order.Target, Color.Green));
 

OpenRA.Mods.Common/Traits/Conditions/GrantExternalConditionToCrusher.cs

@@ -44,20 +44,16 @@ namespace OpenRA.Mods.Common.Traits
 
 		void INotifyCrushed.OnCrush(Actor self, Actor crusher, BitSet<CrushClass> crushClasses)
 		{
-			var external = crusher.TraitsImplementing<ExternalCondition>()
-				.FirstOrDefault(t => t.Info.Condition == Info.OnCrushCondition && t.CanGrantCondition(crusher, self));
-
-			if (external != null)
-				external.GrantCondition(crusher, self, Info.OnCrushDuration);
+			crusher.TraitsImplementing<ExternalCondition>()
+				.FirstOrDefault(t => t.Info.Condition == Info.OnCrushCondition && t.CanGrantCondition(crusher, self))
+				?.GrantCondition(crusher, self, Info.OnCrushDuration);
 		}
 
 		void INotifyCrushed.WarnCrush(Actor self, Actor crusher, BitSet<CrushClass> crushClasses)
 		{
-			var external = crusher.TraitsImplementing<ExternalCondition>()
-				.FirstOrDefault(t => t.Info.Condition == Info.WarnCrushCondition && t.CanGrantCondition(crusher, self));
-
-			if (external != null)
-				external.GrantCondition(crusher, self, Info.WarnCrushDuration);
+			crusher.TraitsImplementing<ExternalCondition>()
+				.FirstOrDefault(t => t.Info.Condition == Info.WarnCrushCondition && t.CanGrantCondition(crusher, self))
+				?.GrantCondition(crusher, self, Info.WarnCrushDuration);
 		}
 	}
 }

OpenRA.Mods.Common/Traits/Conditions/GrantExternalConditionToProduced.cs

@@ -36,11 +36,9 @@ namespace OpenRA.Mods.Common.Traits
 			if (IsTraitDisabled || other.IsDead)
 				return;
 
-			var external = other.TraitsImplementing<ExternalCondition>()
-				.FirstOrDefault(t => t.Info.Condition == Info.Condition && t.CanGrantCondition(other, self));
-
-			if (external != null)
-				external.GrantCondition(other, self, Info.Duration);
+			other.TraitsImplementing<ExternalCondition>()
+				.FirstOrDefault(t => t.Info.Condition == Info.Condition && t.CanGrantCondition(other, self))
+				?.GrantCondition(other, self, Info.Duration);
 		}
 	}
 }

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

@@ -248,9 +248,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			self.World.AddToMaps(self, this);
 
-			var cs = self.World.WorldActor.TraitOrDefault<CrateSpawner>();
-			if (cs != null)
-				cs.IncrementCrates();
+			self.World.WorldActor.TraitOrDefault<CrateSpawner>()?.IncrementCrates();
 
 			if (self.World.Map.DistanceAboveTerrain(CenterPosition) > WDist.Zero && self.TraitOrDefault<Parachutable>() != null)
 				self.QueueActivity(new Parachute(self));
@@ -260,9 +258,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			self.World.RemoveFromMaps(self, this);
 
-			var cs = self.World.WorldActor.TraitOrDefault<CrateSpawner>();
-			if (cs != null)
-				cs.DecrementCrates();
+			self.World.WorldActor.TraitOrDefault<CrateSpawner>()?.DecrementCrates();
 		}
 	}
 }

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

@@ -72,9 +72,7 @@ namespace OpenRA.Mods.Common.Traits
 				var recipient = actor;	// loop variable in closure hazard
 				recipient.World.AddFrameEndTask(w =>
 				{
-					var gainsExperience = recipient.TraitOrDefault<GainsExperience>();
-					if (gainsExperience != null)
-						gainsExperience.GiveLevels(info.Levels);
+					recipient.TraitOrDefault<GainsExperience>()?.GiveLevels(info.Levels);
 				});
 			}
 

OpenRA.Mods.Common/Traits/EjectOnDeath.cs

@@ -90,11 +90,7 @@ namespace OpenRA.Mods.Common.Traits
 				var pilot = self.World.CreateActor(true, Info.PilotActor.ToLowerInvariant(), td);
 
 				if (!inAir)
-				{
-					var pilotMobile = pilot.TraitOrDefault<Mobile>();
-					if (pilotMobile != null)
-						pilotMobile.Nudge(pilot);
-				}
+					pilot.TraitOrDefault<Mobile>()?.Nudge(pilot);
 				else
 					Game.Sound.Play(SoundType.World, Info.ChuteSound, cp);
 			});

OpenRA.Mods.Common/Traits/GivesExperience.cs

@@ -66,9 +66,8 @@ namespace OpenRA.Mods.Common.Traits
 				killer.GiveExperience(Util.ApplyPercentageModifiers(exp, killerExperienceModifier));
 			}
 
-			var attackerExp = e.Attacker.Owner.PlayerActor.TraitOrDefault<PlayerExperience>();
-			if (attackerExp != null)
-				attackerExp.GiveExperience(Util.ApplyPercentageModifiers(exp, new[] { info.PlayerExperienceModifier }));
+			e.Attacker.Owner.PlayerActor.TraitOrDefault<PlayerExperience>()
+				?.GiveExperience(Util.ApplyPercentageModifiers(exp, new[] { info.PlayerExperienceModifier }));
 		}
 	}
 }

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

@@ -26,9 +26,7 @@ namespace OpenRA.Mods.Common.Traits
 				if (!building.AppearsFriendlyTo(self))
 					return;
 
-				var rb = building.TraitOrDefault<RepairableBuilding>();
-				if (rb != null)
-					rb.RepairBuilding(building, self.Owner);
+				building.TraitOrDefault<RepairableBuilding>()?.RepairBuilding(building, self.Owner);
 			}
 		}
 	}

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

@@ -80,8 +80,7 @@ namespace OpenRA.Mods.Common.Traits
 						if (p != self.Owner && p.IsAlliedWith(self.Owner) && p != e.Attacker.Owner)
 							Game.Sound.PlayNotification(rules, p, "Speech", info.AllyNotification, p.Faction.InternalName);
 
-				if (radarPings != null)
-					radarPings.Add(() => self.Owner.IsAlliedWith(self.World.RenderPlayer), self.CenterPosition, info.RadarPingColor, info.RadarPingDuration);
+				radarPings?.Add(() => self.Owner.IsAlliedWith(self.World.RenderPlayer), self.CenterPosition, info.RadarPingColor, info.RadarPingDuration);
 			}
 
 			lastAttackTime = self.World.WorldTick;

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

@@ -244,10 +244,7 @@ namespace OpenRA.Mods.Common.Traits
 
 				case "DevPlayerExperience":
 				{
-					var playerExperience = self.Owner.PlayerActor.TraitOrDefault<PlayerExperience>();
-					if (playerExperience != null)
-						playerExperience.GiveExperience((int)order.ExtraData);
-
+					self.Owner.PlayerActor.TraitOrDefault<PlayerExperience>()?.GiveExperience((int)order.ExtraData);
 					break;
 				}
 

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

@@ -61,8 +61,7 @@ namespace OpenRA.Mods.Common.Traits
 			{
 				Game.Sound.PlayNotification(self.World.Map.Rules, self.Owner, "Speech", info.Notification, self.Owner.Faction.InternalName);
 
-				if (radarPings != null)
-					radarPings.Add(() => self.Owner.IsAlliedWith(self.World.RenderPlayer), self.CenterPosition, info.RadarPingColor, info.RadarPingDuration);
+				radarPings?.Add(() => self.Owner.IsAlliedWith(self.World.RenderPlayer), self.CenterPosition, info.RadarPingColor, info.RadarPingDuration);
 			}
 
 			lastAttackTime = self.World.WorldTick;

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

@@ -170,8 +170,7 @@ namespace OpenRA.Mods.Common.Traits
 						foreach (var t in buildingInfo.Tiles(targetLocation))
 						{
 							var host = buildingInfluence.GetBuildingAt(t);
-							if (host != null)
-								host.World.Remove(host);
+							host?.World.Remove(host);
 						}
 					}
 
@@ -193,14 +192,10 @@ namespace OpenRA.Mods.Common.Traits
 
 				queue.EndProduction(item);
 
+				// FindBaseProvider may return null if the build anywhere cheat is active
+				// BuildingInfo.IsCloseEnoughToBase has already verified that this is a valid build location
 				if (buildingInfo.RequiresBaseProvider)
-				{
-					// May be null if the build anywhere cheat is active
-					// BuildingInfo.IsCloseEnoughToBase has already verified that this is a valid build location
-					var provider = buildingInfo.FindBaseProvider(w, self.Owner, targetLocation);
-					if (provider != null)
-						provider.BeginCooldown();
-				}
+					buildingInfo.FindBaseProvider(w, self.Owner, targetLocation)?.BeginCooldown();
 
 				if (GetNumBuildables(self.Owner) > prevItems)
 					triggerNotification = true;

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

@@ -61,8 +61,7 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			terrainColor[uv] = GetColor(world.Map, uv);
 
-			if (CellTerrainColorChanged != null)
-				CellTerrainColorChanged(uv);
+			CellTerrainColorChanged?.Invoke(uv);
 		}
 
 		public void WorldLoaded(World w, WorldRenderer wr)

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

@@ -465,9 +465,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		protected void PauseProduction(string itemName, bool paused)
 		{
-			var item = Queue.FirstOrDefault(a => a.Item == itemName);
-			if (item != null)
-				item.Pause(paused);
+			Queue.FirstOrDefault(a => a.Item == itemName)?.Pause(paused);
 		}
 
 		protected void CancelProduction(string itemName, uint numberToCancel)
@@ -646,8 +644,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			if (Done)
 			{
-				if (OnComplete != null)
-					OnComplete();
+				OnComplete?.Invoke();
 
 				return;
 			}

OpenRA.Mods.Common/Traits/Render/WithMakeAnimation.cs

@@ -105,14 +105,11 @@ namespace OpenRA.Mods.Common.Traits.Render
 		{
 			Reverse(self, () =>
 			{
-				var wsb = wsbs.FirstEnabledTraitOrDefault();
-
 				// HACK: The actor remains alive and active for one tick before the followup activity
 				// (sell/transform/etc) runs. This causes visual glitches that we attempt to minimize
 				// by forcing the animation to frame 0 and regranting the make condition.
 				// These workarounds will break the actor if the followup activity doesn't dispose it!
-				if (wsb != null)
-					wsb.DefaultAnimation.PlayFetchIndex(info.Sequence, () => 0);
+				wsbs.FirstEnabledTraitOrDefault()?.DefaultAnimation.PlayFetchIndex(info.Sequence, () => 0);
 
 				token = self.GrantCondition(info.Condition);
 

OpenRA.Mods.Common/Traits/Render/WithParachute.cs

@@ -159,8 +159,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 
 		void ITick.Tick(Actor self)
 		{
-			if (shadow != null)
-				shadow.Tick();
+			shadow?.Tick();
 		}
 
 		IEnumerable<IRenderable> IRender.Render(Actor self, WorldRenderer wr)

OpenRA.Mods.Common/Traits/Render/WithSpriteBody.cs

@@ -97,8 +97,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 			DefaultAnimation.PlayThen(NormalizeSequence(self, name), () =>
 			{
 				CancelCustomAnimation(self);
-				if (after != null)
-					after();
+				after?.Invoke();
 			});
 		}
 
@@ -112,8 +111,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 			DefaultAnimation.PlayBackwardsThen(NormalizeSequence(self, name), () =>
 			{
 				CancelCustomAnimation(self);
-				if (after != null)
-					after();
+				after?.Invoke();
 			});
 		}
 

OpenRA.Mods.Common/Traits/Render/WithSpriteTurret.cs

@@ -132,8 +132,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 			DefaultAnimation.PlayThen(NormalizeSequence(self, name), () =>
 			{
 				CancelCustomAnimation(self);
-				if (after != null)
-					after();
+				after?.Invoke();
 			});
 		}
 

OpenRA.Mods.Common/Traits/Sound/AnnounceOnSeen.cs

@@ -57,8 +57,8 @@ namespace OpenRA.Mods.Common.Traits.Sound
 				Game.Sound.PlayNotification(self.World.Map.Rules, discoverer, "Speech", Info.Notification, discoverer.Faction.InternalName);
 
 			// Radar notification
-			if (Info.PingRadar && radarPings.Value != null)
-				radarPings.Value.Add(() => true, self.CenterPosition, Color.Red, 50);
+			if (Info.PingRadar)
+				radarPings.Value?.Add(() => true, self.CenterPosition, Color.Red, 50);
 		}
 	}
 }

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

@@ -83,13 +83,9 @@ namespace OpenRA.Mods.Common.Traits
 			Game.Sound.Play(SoundType.World, info.OnFireSound, order.Target.CenterPosition);
 
 			foreach (var a in UnitsInRange(self.World.Map.CellContaining(order.Target.CenterPosition)))
-			{
-				var external = a.TraitsImplementing<ExternalCondition>()
-					.FirstOrDefault(t => t.Info.Condition == info.Condition && t.CanGrantCondition(a, self));
-
-				if (external != null)
-					external.GrantCondition(a, self, info.Duration);
-			}
+				a.TraitsImplementing<ExternalCondition>()
+					.FirstOrDefault(t => t.Info.Condition == info.Condition && t.CanGrantCondition(a, self))
+					?.GrantCondition(a, self, info.Duration);
 		}
 
 		public IEnumerable<Actor> UnitsInRange(CPos xy)

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

@@ -227,10 +227,8 @@ namespace OpenRA.Mods.Common.Traits
 				return;
 
 			var power = Instances.FirstOrDefault(i => !i.IsTraitPaused);
-			if (power == null)
-				return;
 
-			power.SelectTarget(power.Self, Key, Manager);
+			power?.SelectTarget(power.Self, Key, Manager);
 		}
 
 		public virtual void Activate(Order order)

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

@@ -381,8 +381,7 @@ namespace OpenRA.Mods.Common.Traits
 					foreach (var t in triggers)
 						t.Dirty = true;
 
-				if (CellUpdated != null)
-					CellUpdated(c.Cell);
+				CellUpdated?.Invoke(c.Cell);
 			}
 		}
 
@@ -403,8 +402,7 @@ namespace OpenRA.Mods.Common.Traits
 					foreach (var t in triggers)
 						t.Dirty = true;
 
-				if (CellUpdated != null)
-					CellUpdated(c.Cell);
+				CellUpdated?.Invoke(c.Cell);
 			}
 		}
 

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

@@ -49,8 +49,7 @@ namespace OpenRA.Mods.Common.Traits
 			ClearRedo();
 			undoStack.Push(actionContainer);
 
-			if (ItemAdded != null)
-				ItemAdded(actionContainer);
+			ItemAdded?.Invoke(actionContainer);
 		}
 
 		public void Undo()
@@ -66,8 +65,7 @@ namespace OpenRA.Mods.Common.Traits
 			editorAction.Status = EditorActionStatus.Future;
 			redoStack.Push(editorAction);
 
-			if (OnChange != null)
-				OnChange();
+			OnChange?.Invoke();
 		}
 
 		void ClearRedo()
@@ -76,8 +74,7 @@ namespace OpenRA.Mods.Common.Traits
 			{
 				var item = redoStack.Pop();
 
-				if (ItemRemoved != null)
-					ItemRemoved(item);
+				ItemRemoved?.Invoke(item);
 			}
 		}
 
@@ -95,8 +92,7 @@ namespace OpenRA.Mods.Common.Traits
 			undoStack.Peek().Status = EditorActionStatus.History;
 			undoStack.Push(editorAction);
 
-			if (OnChange != null)
-				OnChange();
+			OnChange?.Invoke();
 		}
 
 		public bool HasUndos()

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

@@ -92,8 +92,7 @@ namespace OpenRA.Mods.Common.Traits
 			UpdateNetWorth(t.Type, t.Density, newTile.Type, newTile.Density);
 			Tiles[uv] = newTile;
 			Map.CustomTerrain[uv] = newTerrain;
-			if (CellChanged != null)
-				CellChanged(cell, type);
+			CellChanged?.Invoke(cell, type);
 
 			// Neighbouring cell density depends on this cell
 			foreach (var d in CVec.Directions)
@@ -111,8 +110,7 @@ namespace OpenRA.Mods.Common.Traits
 				neighbouringTile.Density = density;
 				Tiles[neighbouringCell] = neighbouringTile;
 
-				if (CellChanged != null)
-					CellChanged(neighbouringCell, type);
+				CellChanged?.Invoke(neighbouringCell, type);
 			}
 		}
 

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

@@ -158,8 +158,7 @@ namespace OpenRA.Mods.Common.Traits
 			cell.Density = Math.Min(cell.Type.Info.MaxDensity, cell.Density + n);
 			Content[p] = cell;
 
-			if (CellChanged != null)
-				CellChanged(p, cell.Type);
+			CellChanged?.Invoke(p, cell.Type);
 		}
 
 		public bool IsFull(CPos cell)
@@ -183,8 +182,7 @@ namespace OpenRA.Mods.Common.Traits
 			else
 				Content[cell] = c;
 
-			if (CellChanged != null)
-				CellChanged(cell, c.Type);
+			CellChanged?.Invoke(cell, c.Type);
 
 			return c.Type;
 		}
@@ -202,8 +200,7 @@ namespace OpenRA.Mods.Common.Traits
 			Content[cell] = ResourceLayerContents.Empty;
 			world.Map.CustomTerrain[cell] = byte.MaxValue;
 
-			if (CellChanged != null)
-				CellChanged(cell, c.Type);
+			CellChanged?.Invoke(cell, c.Type);
 		}
 
 		public ResourceType GetResourceType(CPos cell) { return Content[cell].Type; }

OpenRA.Mods.Common/UpdateRules/Rules/20200503/MoveClassicFacingFudge.cs

@@ -70,8 +70,7 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 			foreach (var sequence in sequenceNode.Value.Nodes)
 			{
 				var facingFudgeNode = sequence.LastChildMatching("UseClassicFacingFudge");
-				if (facingFudgeNode != null)
-					facingFudgeNode.RenameKey("UseClassicFacings");
+				facingFudgeNode?.RenameKey("UseClassicFacings");
 			}
 
 			yield break;

OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs

@@ -263,8 +263,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 		public static void Save(this YamlFileSet files)
 		{
 			foreach (var file in files)
-				if (file.Item1 != null)
-					file.Item1.Update(file.Item2, Encoding.UTF8.GetBytes(file.Item3.WriteToString()));
+				file.Item1?.Update(file.Item2, Encoding.UTF8.GetBytes(file.Item3.WriteToString()));
 		}
 
 		/// <summary>Checks if node is a removal (has '-' prefix)</summary>

OpenRA.Mods.Common/Warheads/GrantExternalConditionWarhead.cs

@@ -38,11 +38,9 @@ namespace OpenRA.Mods.Common.Warheads
 				if (!IsValidAgainst(a, firedBy))
 					continue;
 
-				var external = a.TraitsImplementing<ExternalCondition>()
-					.FirstOrDefault(t => t.Info.Condition == Condition && t.CanGrantCondition(a, firedBy));
-
-				if (external != null)
-					external.GrantCondition(a, firedBy, Duration);
+				a.TraitsImplementing<ExternalCondition>()
+					.FirstOrDefault(t => t.Info.Condition == Condition && t.CanGrantCondition(a, firedBy))
+					?.GrantCondition(a, firedBy, Duration);
 			}
 		}
 	}

OpenRA.Mods.Common/Widgets/ConfirmationDialogs.cs

@@ -71,8 +71,7 @@ namespace OpenRA.Mods.Common.Widgets
 				cancelButton.OnClick = () =>
 				{
 					Ui.CloseWindow();
-					if (onCancel != null)
-						onCancel();
+					onCancel?.Invoke();
 				};
 
 				if (!string.IsNullOrEmpty(cancelText) && cancelButton != null)
@@ -85,8 +84,7 @@ namespace OpenRA.Mods.Common.Widgets
 				otherButton.Bounds.Y += headerHeight;
 				otherButton.OnClick = () =>
 				{
-					if (onOther != null)
-						onOther();
+					onOther?.Invoke();
 				};
 
 				if (!string.IsNullOrEmpty(otherText) && otherButton != null)
@@ -156,8 +154,7 @@ namespace OpenRA.Mods.Common.Widgets
 			cancelButton.OnClick = () =>
 			{
 				Ui.CloseWindow();
-				if (onCancel != null)
-					onCancel();
+				onCancel?.Invoke();
 			};
 
 			// Validation

OpenRA.Mods.Common/Widgets/DropDownButtonWidget.cs

@@ -129,9 +129,7 @@ namespace OpenRA.Mods.Common.Widgets
 				oldBounds.Height);
 			panelRoot.AddChild(panel);
 
-			var scrollPanel = panel as ScrollPanelWidget;
-			if (scrollPanel != null)
-				scrollPanel.ScrollToSelectedItem();
+			(panel as ScrollPanelWidget)?.ScrollToSelectedItem();
 		}
 
 		public void ShowDropDown<T>(string panelTemplate, int maxHeight, IEnumerable<T> options, Func<T, ScrollItemWidget, ScrollItemWidget> setupItem)

OpenRA.Mods.Common/Widgets/EditorViewportControllerWidget.cs

@@ -52,8 +52,7 @@ namespace OpenRA.Mods.Common.Widgets
 		public void ClearBrush() { SetBrush(null); }
 		public void SetBrush(IEditorBrush brush)
 		{
-			if (CurrentBrush != null)
-				CurrentBrush.Dispose();
+			CurrentBrush?.Dispose();
 
 			CurrentBrush = brush ?? DefaultBrush;
 		}