Move ChildActivity handling into base Activity class.

OpenRA.Game/Activities/Activity.cs

@@ -41,11 +41,13 @@ namespace OpenRA.Activities
 		public Activity NextActivity { get; protected set; }
 
 		public bool IsInterruptible { get; protected set; }
+		public bool ChildHasPriority { get; protected set; }
 		public bool IsCanceling { get { return State == ActivityState.Canceling; } }
 
 		public Activity()
 		{
 			IsInterruptible = true;
+			ChildHasPriority = true;
 		}
 
 		public Activity TickOuter(Actor self)
@@ -59,7 +61,18 @@ namespace OpenRA.Activities
 				State = ActivityState.Active;
 			}
 
+			if (ChildHasPriority)
+			{
+				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
+				if (ChildActivity != null)
+					return this;
+			}
+
 			var ret = Tick(self);
+
+			if (ChildActivity != null && ChildActivity.State == ActivityState.Queued)
+				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
+
 			if (ret != this)
 			{
 				State = ActivityState.Done;
@@ -113,20 +126,20 @@ namespace OpenRA.Activities
 			State = ActivityState.Canceling;
 		}
 
-		public virtual void Queue(Actor self, Activity activity)
+		public void Queue(Activity activity)
 		{
 			if (NextActivity != null)
-				NextActivity.Queue(self, activity);
+				NextActivity.Queue(activity);
 			else
 				NextActivity = activity;
 		}
 
-		public virtual void QueueChild(Actor self, Activity activity, bool pretick = false)
+		public void QueueChild(Activity activity)
 		{
 			if (ChildActivity != null)
-				ChildActivity.Queue(self, activity);
+				ChildActivity.Queue(activity);
 			else
-				ChildActivity = pretick ? ActivityUtils.RunActivity(self, activity) : activity;
+				ChildActivity = activity;
 		}
 
 		/// <summary>
@@ -187,15 +200,4 @@ namespace OpenRA.Activities
 					yield return a;
 		}
 	}
-
-	public static class ActivityExts
-	{
-		public static IEnumerable<Target> GetTargetQueue(this Actor self)
-		{
-			return self.CurrentActivity
-				.Iterate(u => u.NextActivity)
-				.TakeWhile(u => u != null)
-				.SelectMany(u => u.GetTargets(self));
-		}
-	}
 }

OpenRA.Game/Actor.cs

@@ -222,7 +222,7 @@ namespace OpenRA
 			if (CurrentActivity == null)
 				CurrentActivity = nextActivity;
 			else
-				CurrentActivity.Queue(this, nextActivity);
+				CurrentActivity.Queue(nextActivity);
 		}
 
 		public void CancelActivity()

OpenRA.Game/Traits/ActivityUtils.cs

@@ -51,10 +51,10 @@ namespace OpenRA.Traits
 			return act;
 		}
 
-		public static Activity SequenceActivities(Actor self, params Activity[] acts)
+		public static Activity SequenceActivities(params Activity[] acts)
 		{
 			return acts.Reverse().Aggregate(
-				(next, a) => { a.Queue(self, next); return a; });
+				(next, a) => { a.Queue(next); return a; });
 		}
 	}
 }

OpenRA.Mods.Cnc/Activities/LayMines.cs

@@ -39,12 +39,6 @@ namespace OpenRA.Mods.Cnc.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				return this;
-			}
-
 			if (IsCanceling)
 				return NextActivity;
 
@@ -59,16 +53,16 @@ namespace OpenRA.Mods.Cnc.Activities
 					return NextActivity;
 
 				// Add a CloseEnough range of 512 to the Rearm/Repair activities in order to ensure that we're at the host actor
-				QueueChild(self, new MoveAdjacentTo(self, Target.FromActor(rearmTarget)), true);
+				QueueChild(new MoveAdjacentTo(self, Target.FromActor(rearmTarget)));
-				QueueChild(self, movement.MoveTo(self.World.Map.CellContaining(rearmTarget.CenterPosition), rearmTarget));
+				QueueChild(movement.MoveTo(self.World.Map.CellContaining(rearmTarget.CenterPosition), rearmTarget));
-				QueueChild(self, new Resupply(self, rearmTarget, new WDist(512)));
+				QueueChild(new Resupply(self, rearmTarget, new WDist(512)));
 				return this;
 			}
 
 			if ((minefield == null || minefield.Contains(self.Location)) && ShouldLayMine(self, self.Location))
 			{
 				LayMine(self);
-				QueueChild(self, new Wait(20), true); // A little wait after placing each mine, for show
+				QueueChild(new Wait(20)); // A little wait after placing each mine, for show
 				return this;
 			}
 
@@ -80,7 +74,7 @@ namespace OpenRA.Mods.Cnc.Activities
 					var p = minefield.Random(self.World.SharedRandom);
 					if (ShouldLayMine(self, p))
 					{
-						QueueChild(self, movement.MoveTo(p, 0), true);
+						QueueChild(movement.MoveTo(p, 0));
 						return this;
 					}
 				}

OpenRA.Mods.Cnc/Activities/Leap.cs

@@ -72,18 +72,9 @@ namespace OpenRA.Mods.Cnc.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (canceled)
-				return NextActivity;
-
 			// Correct the visual position after we jumped
-			if (jumpComplete)
+			if (canceled || jumpComplete)
-			{
+				return NextActivity;
-				if (ChildActivity == null)
-					return NextActivity;
-
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				return this;
-			}
 
 			if (target.Type != TargetType.Invalid)
 				targetPosition = target.CenterPosition;
@@ -106,9 +97,7 @@ namespace OpenRA.Mods.Cnc.Activities
 				attack.DoAttack(self, target);
 
 				jumpComplete = true;
-				QueueChild(self, mobile.VisualMove(self, position, self.World.Map.CenterOfSubCell(destinationCell, destinationSubCell)), true);
+				QueueChild(mobile.VisualMove(self, position, self.World.Map.CenterOfSubCell(destinationCell, destinationSubCell)));
-
-				return this;
 			}
 
 			return this;

OpenRA.Mods.Cnc/Activities/LeapAttack.cs

@@ -74,13 +74,6 @@ namespace OpenRA.Mods.Cnc.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			// Run this even if the target became invalid to avoid visual glitches
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				return this;
-			}
-
 			if (IsCanceling)
 				return NextActivity;
 
@@ -114,7 +107,7 @@ namespace OpenRA.Mods.Cnc.Activities
 				if (!allowMovement || lastVisibleMaxRange == WDist.Zero || lastVisibleMaxRange < lastVisibleMinRange)
 					return NextActivity;
 
-				QueueChild(self, mobile.MoveWithinRange(target, lastVisibleMinRange, lastVisibleMaxRange, checkTarget.CenterPosition, Color.Red), true);
+				QueueChild(mobile.MoveWithinRange(target, lastVisibleMinRange, lastVisibleMaxRange, checkTarget.CenterPosition, Color.Red));
 				return this;
 			}
 
@@ -144,11 +137,11 @@ namespace OpenRA.Mods.Cnc.Activities
 			var desiredFacing = (destination - origin).Yaw.Facing;
 			if (mobile.Facing != desiredFacing)
 			{
-				QueueChild(self, new Turn(self, desiredFacing), true);
+				QueueChild(new Turn(self, desiredFacing));
 				return this;
 			}
 
-			QueueChild(self, new Leap(self, target, mobile, targetMobile, info.Speed.Length, attack, edible), true);
+			QueueChild(new Leap(self, target, mobile, targetMobile, info.Speed.Length, attack, edible));
 
 			// Re-queue the child activities to kill the target if it didn't die in one go
 			return this;

OpenRA.Mods.Cnc/Traits/Attack/AttackTesla.cs

@@ -96,13 +96,6 @@ namespace OpenRA.Mods.Cnc.Traits
 
 			public override Activity Tick(Actor self)
 			{
-				if (ChildActivity != null)
-				{
-					ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-					if (ChildActivity != null)
-						return this;
-				}
-
 				if (IsCanceling || !attack.CanAttack(self, target))
 					return NextActivity;
 
@@ -115,8 +108,8 @@ namespace OpenRA.Mods.Cnc.Traits
 				if (!string.IsNullOrEmpty(attack.info.ChargeAudio))
 					Game.Sound.Play(SoundType.World, attack.info.ChargeAudio, self.CenterPosition);
 
-				QueueChild(self, new Wait(attack.info.InitialChargeDelay), true);
+				QueueChild(new Wait(attack.info.InitialChargeDelay));
-				QueueChild(self, new ChargeFire(attack, target));
+				QueueChild(new ChargeFire(attack, target));
 				return this;
 			}
 
@@ -154,13 +147,6 @@ namespace OpenRA.Mods.Cnc.Traits
 
 			public override Activity Tick(Actor self)
 			{
-				if (ChildActivity != null)
-				{
-					ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-					if (ChildActivity != null)
-						return this;
-				}
-
 				if (IsCanceling || !attack.CanAttack(self, target))
 					return NextActivity;
 
@@ -169,7 +155,7 @@ namespace OpenRA.Mods.Cnc.Traits
 
 				attack.DoAttack(self, target);
 
-				QueueChild(self, new Wait(attack.info.ChargeDelay), true);
+				QueueChild(new Wait(attack.info.ChargeDelay));
 				return this;
 			}
 		}

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

@@ -102,13 +102,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			// Refuse to take off if it would land immediately again.
 			if (aircraft.ForceLanding)
 				Cancel(self);
@@ -125,7 +118,7 @@ namespace OpenRA.Mods.Common.Activities
 				if (aircraft.Info.CanHover && !skipHeightAdjustment && dat != aircraft.Info.CruiseAltitude)
 				{
 					if (dat <= aircraft.LandAltitude)
-						QueueChild(self, new TakeOff(self, target), true);
+						QueueChild(new TakeOff(self, target));
 					else
 						VerticalTakeOffOrLandTick(self, aircraft, aircraft.Facing, aircraft.Info.CruiseAltitude);
 
@@ -136,7 +129,7 @@ namespace OpenRA.Mods.Common.Activities
 			}
 			else if (dat <= aircraft.LandAltitude)
 			{
-				QueueChild(self, new TakeOff(self, target), true);
+				QueueChild(new TakeOff(self, target));
 				return this;
 			}
 

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

@@ -65,13 +65,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			// Refuse to take off if it would land immediately again.
 			if (aircraft.ForceLanding)
 				Cancel(self);
@@ -121,7 +114,7 @@ namespace OpenRA.Mods.Common.Activities
 			// If all valid weapons have depleted their ammo and Rearmable trait exists, return to RearmActor to reload and then resume the activity
 			if (rearmable != null && !useLastVisibleTarget && attackAircraft.Armaments.All(x => x.IsTraitPaused || !x.Weapon.IsValidAgainst(target, self.World, self)))
 			{
-				QueueChild(self, new ReturnToBase(self, aircraft.Info.AbortOnResupply), true);
+				QueueChild(new ReturnToBase(self, aircraft.Info.AbortOnResupply));
 				return this;
 			}
 
@@ -139,7 +132,7 @@ namespace OpenRA.Mods.Common.Activities
 				}
 
 				// Fly towards the last known position
-				QueueChild(self, new Fly(self, target, WDist.Zero, lastVisibleMaximumRange, checkTarget.CenterPosition, Color.Red), true);
+				QueueChild(new Fly(self, target, WDist.Zero, lastVisibleMaximumRange, checkTarget.CenterPosition, Color.Red));
 				return this;
 			}
 
@@ -148,21 +141,21 @@ namespace OpenRA.Mods.Common.Activities
 			var isAirborne = self.World.Map.DistanceAboveTerrain(pos).Length >= aircraft.Info.MinAirborneAltitude;
 
 			if (!isAirborne)
-				QueueChild(self, new TakeOff(self), true);
+				QueueChild(new TakeOff(self));
 
 			if (attackAircraft.Info.AttackType == AirAttackType.Strafe)
 			{
 				if (target.IsInRange(pos, attackAircraft.GetMinimumRange()))
-					QueueChild(self, new FlyTimed(ticksUntilTurn, self), true);
+					QueueChild(new FlyTimed(ticksUntilTurn, self));
 
-				QueueChild(self, new Fly(self, target, target.CenterPosition, Color.Red), true);
+				QueueChild(new Fly(self, target, target.CenterPosition, Color.Red));
-				QueueChild(self, new FlyTimed(ticksUntilTurn, self));
+				QueueChild(new FlyTimed(ticksUntilTurn, self));
 			}
 			else
 			{
 				var minimumRange = attackAircraft.GetMinimumRangeVersusTarget(target);
 				if (!target.IsInRange(pos, lastVisibleMaximumRange) || target.IsInRange(pos, minimumRange))
-					QueueChild(self, new Fly(self, target, minimumRange, lastVisibleMaximumRange, target.CenterPosition, Color.Red), true);
+					QueueChild(new Fly(self, target, minimumRange, lastVisibleMaximumRange, target.CenterPosition, Color.Red));
 				else if (isAirborne) // Don't use 'else' to avoid conflict with TakeOff
 					Fly.VerticalTakeOffOrLandTick(self, aircraft, desiredFacing, aircraft.Info.CruiseAltitude);
 			}

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

@@ -47,13 +47,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			// Refuse to take off if it would land immediately again.
 			if (aircraft.ForceLanding)
 				Cancel(self);
@@ -96,7 +89,7 @@ namespace OpenRA.Mods.Common.Activities
 			}
 
 			wasMovingWithinRange = true;
-			QueueChild(self, aircraft.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, targetLineColor), true);
+			QueueChild(aircraft.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, targetLineColor));
 			return this;
 		}
 	}

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

@@ -73,13 +73,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling || target.Type == TargetType.Invalid)
 			{
 				if (landingInitiated)
@@ -94,7 +87,7 @@ namespace OpenRA.Mods.Common.Activities
 						var dat = self.World.Map.DistanceAboveTerrain(aircraft.CenterPosition);
 						if (dat > aircraft.LandAltitude && dat < aircraft.Info.CruiseAltitude)
 						{
-							QueueChild(self, new TakeOff(self), true);
+							QueueChild(new TakeOff(self));
 							return this;
 						}
 
@@ -125,7 +118,7 @@ namespace OpenRA.Mods.Common.Activities
 				if (!newLocation.HasValue)
 				{
 					Cancel(self, true);
-					QueueChild(self, aircraft.MoveTo(landingCell, 0), true);
+					QueueChild(aircraft.MoveTo(landingCell, 0));
 					return this;
 				}
 
@@ -140,10 +133,10 @@ namespace OpenRA.Mods.Common.Activities
 			// Move towards landing location
 			if (aircraft.Info.VTOL && (pos - targetPosition).HorizontalLengthSquared != 0)
 			{
-				QueueChild(self, new Fly(self, Target.FromPos(targetPosition)), true);
+				QueueChild(new Fly(self, Target.FromPos(targetPosition)));
 
 				if (desiredFacing != -1)
-					QueueChild(self, new Turn(self, desiredFacing));
+					QueueChild(new Turn(self, desiredFacing));
 
 				return this;
 			}
@@ -199,11 +192,11 @@ namespace OpenRA.Mods.Common.Activities
 				turnRadius = Fly.CalculateTurnRadius(aircraft.Info.Speed, aircraft.Info.TurnSpeed);
 
 				// Move along approach trajectory.
-				QueueChild(self, new Fly(self, Target.FromPos(w1), WDist.Zero, new WDist(turnRadius * 3)), true);
+				QueueChild(new Fly(self, Target.FromPos(w1), WDist.Zero, new WDist(turnRadius * 3)));
-				QueueChild(self, new Fly(self, Target.FromPos(w2)), true);
+				QueueChild(new Fly(self, Target.FromPos(w2)));
 
 				// Fix a problem when the airplane is sent to land near the landing cell
-				QueueChild(self, new Fly(self, Target.FromPos(w3), WDist.Zero, new WDist(turnRadius / 2)), true);
+				QueueChild(new Fly(self, Target.FromPos(w3), WDist.Zero, new WDist(turnRadius / 2)));
 				finishedApproach = true;
 				return this;
 			}
@@ -216,9 +209,9 @@ namespace OpenRA.Mods.Common.Activities
 				{
 					// Maintain holding pattern.
 					if (aircraft.Info.CanHover)
-						QueueChild(self, new Wait(25), true);
+						QueueChild(new Wait(25));
 					else
-						QueueChild(self, new FlyCircle(self, 25), true);
+						QueueChild(new FlyCircle(self, 25));
 
 					self.NotifyBlocker(blockingCells);
 					finishedApproach = false;

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

@@ -68,13 +68,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			// Refuse to take off if it would land immediately again.
 			// Special case: Don't kill other deploy hotkey activities.
 			if (aircraft.ForceLanding)
@@ -113,15 +106,14 @@ namespace OpenRA.Mods.Common.Activities
 							var randomPosition = WVec.FromPDF(self.World.SharedRandom, 2) * distanceLength / 1024;
 							var target = Target.FromPos(nearestResupplier.CenterPosition + randomPosition);
 
-							QueueChild(self, new Fly(self, target, WDist.Zero, aircraft.Info.WaitDistanceFromResupplyBase, targetLineColor: Color.Green), true);
+							QueueChild(new Fly(self, target, WDist.Zero, aircraft.Info.WaitDistanceFromResupplyBase, targetLineColor: Color.Green));
 						}
 
 						return this;
 					}
 
-					QueueChild(self, new Fly(self, Target.FromActor(nearestResupplier), WDist.Zero, aircraft.Info.WaitDistanceFromResupplyBase, targetLineColor: Color.Green),
+					QueueChild(new Fly(self, Target.FromActor(nearestResupplier), WDist.Zero, aircraft.Info.WaitDistanceFromResupplyBase, targetLineColor: Color.Green));
-							true);
+					QueueChild(new FlyCircle(self, aircraft.Info.NumberOfTicksToVerifyAvailableAirport));
-					QueueChild(self, new FlyCircle(self, aircraft.Info.NumberOfTicksToVerifyAvailableAirport), true);
 					return this;
 				}
 
@@ -140,13 +132,13 @@ namespace OpenRA.Mods.Common.Activities
 					facing = 192;
 
 				aircraft.MakeReservation(dest);
-				QueueChild(self, new Land(self, Target.FromActor(dest), offset, facing), true);
+				QueueChild(new Land(self, Target.FromActor(dest), offset, facing));
-				QueueChild(self, new Resupply(self, dest, WDist.Zero), true);
+				QueueChild(new Resupply(self, dest, WDist.Zero));
 				if (aircraft.Info.TakeOffOnResupply && !alwaysLand)
-					QueueChild(self, new TakeOff(self));
+					QueueChild(new TakeOff(self));
 			}
 			else
-				QueueChild(self, new Fly(self, Target.FromActor(dest)), true);
+				QueueChild(new Fly(self, Target.FromActor(dest)));
 
 			resupplied = true;
 			return this;

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

@@ -64,13 +64,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			// Refuse to take off if it would land immediately again.
 			if (aircraft.ForceLanding)
 			{
@@ -100,7 +93,7 @@ namespace OpenRA.Mods.Common.Activities
 				if (!aircraft.Info.VTOL && assignTargetOnFirstRun)
 					return NextActivity;
 
-				QueueChild(self, new AttackMoveActivity(self, () => move.MoveToTarget(self, target)), true);
+				QueueChild(new AttackMoveActivity(self, () => move.MoveToTarget(self, target)));
 				moveToRallyPoint = false;
 				return this;
 			}

OpenRA.Mods.Common/Activities/Attack.cs

@@ -85,12 +85,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				return this;
-			}
-
 			if (IsCanceling)
 				return NextActivity;
 
@@ -135,7 +129,7 @@ namespace OpenRA.Mods.Common.Activities
 
 				// Move towards the last known position
 				wasMovingWithinRange = true;
-				QueueChild(self, move.MoveWithinRange(target, WDist.Zero, lastVisibleMaximumRange, checkTarget.CenterPosition, Color.Red), true);
+				QueueChild(move.MoveWithinRange(target, WDist.Zero, lastVisibleMaximumRange, checkTarget.CenterPosition, Color.Red));
 				return this;
 			}
 
@@ -178,7 +172,7 @@ namespace OpenRA.Mods.Common.Activities
 				var sightRange = rs != null ? rs.Range : WDist.FromCells(2);
 
 				attackStatus |= AttackStatus.NeedsToMove;
-				QueueChild(self, move.MoveWithinRange(target, sightRange, target.CenterPosition, Color.Red), true);
+				QueueChild(move.MoveWithinRange(target, sightRange, target.CenterPosition, Color.Red));
 				return AttackStatus.NeedsToMove;
 			}
 
@@ -203,7 +197,7 @@ namespace OpenRA.Mods.Common.Activities
 
 				attackStatus |= AttackStatus.NeedsToMove;
 				var checkTarget = useLastVisibleTarget ? lastVisibleTarget : target;
-				QueueChild(self, move.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, Color.Red), true);
+				QueueChild(move.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, Color.Red));
 				return AttackStatus.NeedsToMove;
 			}
 
@@ -211,7 +205,7 @@ namespace OpenRA.Mods.Common.Activities
 			{
 				var desiredFacing = (attack.GetTargetPosition(pos, target) - pos).Yaw.Facing;
 				attackStatus |= AttackStatus.NeedsToTurn;
-				QueueChild(self, new Turn(self, desiredFacing), true);
+				QueueChild(new Turn(self, desiredFacing));
 				return AttackStatus.NeedsToTurn;
 			}
 

OpenRA.Mods.Common/Activities/DeliverResources.cs

@@ -39,13 +39,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling || isDocking)
 				return NextActivity;
 
@@ -56,7 +49,7 @@ namespace OpenRA.Mods.Common.Activities
 			// No refineries exist; check again after delay defined in Harvester.
 			if (harv.LinkedProc == null)
 			{
-				QueueChild(self, new Wait(harv.Info.SearchForDeliveryBuildingDelay), true);
+				QueueChild(new Wait(harv.Info.SearchForDeliveryBuildingDelay));
 				return this;
 			}
 
@@ -69,13 +62,13 @@ namespace OpenRA.Mods.Common.Activities
 				foreach (var n in self.TraitsImplementing<INotifyHarvesterAction>())
 					n.MovingToRefinery(self, proc, new FindAndDeliverResources(self));
 
-				QueueChild(self, movement.MoveTo(proc.Location + iao.DeliveryOffset, 0), true);
+				QueueChild(movement.MoveTo(proc.Location + iao.DeliveryOffset, 0));
 				return this;
 			}
 
 			if (!isDocking)
 			{
-				QueueChild(self, new Wait(10), true);
+				QueueChild(new Wait(10));
 				isDocking = true;
 				iao.OnDock(self, this);
 				return this;

OpenRA.Mods.Common/Activities/DeliverUnit.cs

@@ -44,20 +44,14 @@ namespace OpenRA.Mods.Common.Activities
 			if (assignTargetOnFirstRun)
 				destination = Target.FromCell(self.World, self.Location);
 
-			QueueChild(self, new Land(self, destination, deliverRange), true);
+			QueueChild(new Land(self, destination, deliverRange));
-			QueueChild(self, new Wait(carryall.Info.BeforeUnloadDelay, false), true);
+			QueueChild(new Wait(carryall.Info.BeforeUnloadDelay, false));
-			QueueChild(self, new ReleaseUnit(self));
+			QueueChild(new ReleaseUnit(self));
-			QueueChild(self, new TakeOff(self));
+			QueueChild(new TakeOff(self));
 		}
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
 
 			return NextActivity;
 		}

OpenRA.Mods.Common/Activities/DeployForGrantedCondition.cs

@@ -33,22 +33,15 @@ namespace OpenRA.Mods.Common.Activities
 		{
 			// Turn to the required facing.
 			if (deploy.DeployState == DeployState.Undeployed && deploy.Info.Facing != -1 && canTurn && !moving)
-				QueueChild(self, new Turn(self, deploy.Info.Facing));
+				QueueChild(new Turn(self, deploy.Info.Facing));
 		}
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling || initiated || (deploy.DeployState != DeployState.Deployed && moving))
 				return NextActivity;
 
-			QueueChild(self, new DeployInner(self, deploy), true);
+			QueueChild(new DeployInner(self, deploy));
 
 			initiated = true;
 			return this;

OpenRA.Mods.Common/Activities/Enter.cs

@@ -35,6 +35,7 @@ namespace OpenRA.Mods.Common.Activities
 			move = self.Trait<IMove>();
 			this.target = target;
 			this.targetLineColor = targetLineColor;
+			ChildHasPriority = false;
 		}
 
 		/// <summary>
@@ -80,12 +81,9 @@ namespace OpenRA.Mods.Common.Activities
 
 			// We need to wait for movement to finish before transitioning to
 			// the next state or next activity
+			ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
 			if (ChildActivity != null)
-			{
+				return this;
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
 
 			// Note that lastState refers to what we have just *finished* doing
 			switch (lastState)
@@ -106,7 +104,7 @@ namespace OpenRA.Mods.Common.Activities
 					{
 						// Target lines are managed by this trait, so we do not pass targetLineColor
 						var initialTargetPosition = (useLastVisibleTarget ? lastVisibleTarget : target).CenterPosition;
-						QueueChild(self, move.MoveToTarget(self, target, initialTargetPosition), true);
+						QueueChild(move.MoveToTarget(self, target, initialTargetPosition));
 						return this;
 					}
 
@@ -119,7 +117,7 @@ namespace OpenRA.Mods.Common.Activities
 					if (TryStartEnter(self, target.Actor))
 					{
 						lastState = EnterState.Entering;
-						QueueChild(self, move.MoveIntoTarget(self, target), true);
+						QueueChild(move.MoveIntoTarget(self, target));
 						return this;
 					}
 
@@ -139,7 +137,7 @@ namespace OpenRA.Mods.Common.Activities
 						OnEnterComplete(self, target.Actor);
 
 					lastState = EnterState.Exiting;
-					QueueChild(self, move.MoveIntoWorld(self, self.Location), true);
+					QueueChild(move.MoveIntoWorld(self, self.Location));
 					return this;
 				}
 

OpenRA.Mods.Common/Activities/FindAndDeliverResources.cs

@@ -65,26 +65,19 @@ namespace OpenRA.Mods.Common.Activities
 				// We have to make sure the actual "harvest" order is not skipped if a third order is queued,
 				// so we keep deliveredLoad false.
 				if (harv.IsFull)
-					QueueChild(self, new DeliverResources(self), true);
+					QueueChild(new DeliverResources(self));
 			}
 
 			// If an explicit "deliver" order is given, the harvester goes immediately to the refinery.
 			if (deliverActor != null)
 			{
-				QueueChild(self, new DeliverResources(self, deliverActor), true);
+				QueueChild(new DeliverResources(self, deliverActor));
 				hasDeliveredLoad = true;
 			}
 		}
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling)
 				return NextActivity;
 
@@ -102,7 +95,7 @@ namespace OpenRA.Mods.Common.Activities
 			// Are we full or have nothing more to gather? Deliver resources.
 			if (harv.IsFull || (!harv.IsEmpty && harv.LastSearchFailed))
 			{
-				QueueChild(self, new DeliverResources(self), true);
+				QueueChild(new DeliverResources(self));
 				hasDeliveredLoad = true;
 				return this;
 			}
@@ -110,7 +103,7 @@ namespace OpenRA.Mods.Common.Activities
 			// After a failed search, wait and sit still for a bit before searching again.
 			if (harv.LastSearchFailed && !hasWaited)
 			{
-				QueueChild(self, new Wait(harv.Info.WaitDuration), true);
+				QueueChild(new Wait(harv.Info.WaitDuration));
 				hasWaited = true;
 				return this;
 			}
@@ -147,7 +140,7 @@ namespace OpenRA.Mods.Common.Activities
 						var unblockCell = deliveryLoc + harv.Info.UnblockCell;
 						var moveTo = mobile.NearestMoveableCell(unblockCell, 1, 5);
 						self.SetTargetLine(Target.FromCell(self.World, moveTo), Color.Green, false);
-						QueueChild(self, mobile.MoveTo(moveTo, 1), true);
+						QueueChild(mobile.MoveTo(moveTo, 1));
 					}
 				}
 
@@ -155,7 +148,7 @@ namespace OpenRA.Mods.Common.Activities
 			}
 
 			// If we get here, our search for resources was successful. Commence harvesting.
-			QueueChild(self, new HarvestResource(self, closestHarvestableCell.Value), true);
+			QueueChild(new HarvestResource(self, closestHarvestableCell.Value));
 			lastHarvestedCell = closestHarvestableCell.Value;
 			hasHarvestedCell = true;
 			return this;

OpenRA.Mods.Common/Activities/HarvestResource.cs

@@ -49,13 +49,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling || harv.IsFull)
 				return NextActivity;
 
@@ -66,7 +59,7 @@ namespace OpenRA.Mods.Common.Activities
 					n.MovingToResources(self, targetCell, new FindAndDeliverResources(self));
 
 				self.SetTargetLine(Target.FromCell(self.World, targetCell), Color.Red, false);
-				QueueChild(self, move.MoveTo(targetCell, 2), true);
+				QueueChild(move.MoveTo(targetCell, 2));
 				return this;
 			}
 
@@ -80,7 +73,7 @@ namespace OpenRA.Mods.Common.Activities
 				var desired = body.QuantizeFacing(current, harvInfo.HarvestFacings);
 				if (desired != current)
 				{
-					QueueChild(self, new Turn(self, desired), true);
+					QueueChild(new Turn(self, desired));
 					return this;
 				}
 			}
@@ -94,7 +87,7 @@ namespace OpenRA.Mods.Common.Activities
 			foreach (var t in self.TraitsImplementing<INotifyHarvesterAction>())
 				t.Harvested(self, resource);
 
-			QueueChild(self, new Wait(harvInfo.BaleLoadDelay), true);
+			QueueChild(new Wait(harvInfo.BaleLoadDelay));
 			return this;
 		}
 

OpenRA.Mods.Common/Activities/HarvesterDockSequence.cs

@@ -47,13 +47,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			switch (dockingState)
 			{
 				case DockingState.Wait:
@@ -61,9 +54,9 @@ namespace OpenRA.Mods.Common.Activities
 
 				case DockingState.Turn:
 					dockingState = DockingState.Dock;
-					QueueChild(self, new Turn(self, DockAngle), true);
+					QueueChild(new Turn(self, DockAngle));
 					if (IsDragRequired)
-						QueueChild(self, new Drag(self, StartDrag, EndDrag, DragLength));
+						QueueChild(new Drag(self, StartDrag, EndDrag, DragLength));
 					return this;
 
 				case DockingState.Dock:
@@ -90,7 +83,7 @@ namespace OpenRA.Mods.Common.Activities
 					Harv.LastLinkedProc = Harv.LinkedProc;
 					Harv.LinkProc(self, null);
 					if (IsDragRequired)
-						QueueChild(self, new Drag(self, EndDrag, StartDrag, DragLength), true);
+						QueueChild(new Drag(self, EndDrag, StartDrag, DragLength));
 
 					dockingState = DockingState.Finished;
 					return this;

OpenRA.Mods.Common/Activities/Hunt.cs

@@ -33,13 +33,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling)
 				return NextActivity;
 
@@ -47,8 +40,8 @@ namespace OpenRA.Mods.Common.Activities
 			if (target == null)
 				return this;
 
-			QueueChild(self, new AttackMoveActivity(self, () => move.MoveTo(target.Location, 2)), true);
+			QueueChild(new AttackMoveActivity(self, () => move.MoveTo(target.Location, 2)));
-			QueueChild(self, new Wait(25));
+			QueueChild(new Wait(25));
 			return this;
 		}
 	}

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

@@ -33,12 +33,13 @@ namespace OpenRA.Mods.Common.Activities
 			conditionManager = self.TraitOrDefault<ConditionManager>();
 			attackMove = self.TraitOrDefault<AttackMove>();
 			isAssaultMove = assaultMoving;
+			ChildHasPriority = false;
 		}
 
 		protected override void OnFirstRun(Actor self)
 		{
 			// Start moving.
-			QueueChild(self, getInner());
+			QueueChild(getInner());
 
 			if (conditionManager == null || attackMove == null)
 				return;
@@ -64,21 +65,18 @@ namespace OpenRA.Mods.Common.Activities
 					foreach (var ab in attackBases)
 					{
 						var activity = ab.GetAttackActivity(self, target, true, false);
-						QueueChild(self, activity);
+						QueueChild(activity);
 						ab.OnQueueAttackActivity(self, activity, target, true, false);
 					}
 
 					// Make sure to continue moving when the attack activities have finished.
-					QueueChild(self, getInner());
+					QueueChild(getInner());
 				}
 			}
 
+			ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
 			if (ChildActivity != null)
-			{
+				return this;
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
 
 			// The last queued childactivity is guaranteed to be the inner move, so if we get here it means
 			// we have reached our destination and there are no more enemies on our path.

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

@@ -47,13 +47,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling)
 				return NextActivity;
 
@@ -90,7 +83,7 @@ namespace OpenRA.Mods.Common.Activities
 
 			// Move into range
 			wasMovingWithinRange = true;
-			QueueChild(self, move.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, targetLineColor), true);
+			QueueChild(move.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, targetLineColor));
 			return this;
 		}
 	}

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

@@ -146,17 +146,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			// Let the child be run so that units will not end up in an odd place.
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-
-				// Child activities such as Turn might have finished.
-				// If we "return this" in this situation, the unit loses one tick and pauses movement briefly.
-				if (ChildActivity != null)
-					return this;
-			}
-
 			// If the actor is inside a tunnel then we must let them move
 			// all the way through before moving to the next activity
 			if (IsCanceling && self.Location.Layer != CustomMovementLayerType.Tunnel)
@@ -188,7 +177,7 @@ namespace OpenRA.Mods.Common.Activities
 			{
 				path.Add(nextCell.Value.First);
 
-				QueueChild(self, new Turn(self, firstFacing), true);
+				QueueChild(new Turn(self, firstFacing));
 				return this;
 			}
 
@@ -202,7 +191,7 @@ namespace OpenRA.Mods.Common.Activities
 			var to = Util.BetweenCells(self.World, mobile.FromCell, mobile.ToCell) +
 				(map.Grid.OffsetOfSubCell(mobile.FromSubCell) + map.Grid.OffsetOfSubCell(mobile.ToSubCell)) / 2;
 
-			QueueChild(self, new MoveFirstHalf(this, from, to, mobile.Facing, mobile.Facing, 0), true);
+			QueueChild(new MoveFirstHalf(this, from, to, mobile.Facing, mobile.Facing, 0));
 			return this;
 		}
 
@@ -335,7 +324,7 @@ namespace OpenRA.Mods.Common.Activities
 				if (ret == this)
 					return ret;
 
-				Queue(self, ret);
+				Queue(ret);
 				return NextActivity;
 			}
 

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

@@ -48,6 +48,7 @@ namespace OpenRA.Mods.Common.Activities
 			Mobile = self.Trait<Mobile>();
 			pathFinder = self.World.WorldActor.Trait<IPathFinder>();
 			domainIndex = self.World.WorldActor.Trait<DomainIndex>();
+			ChildHasPriority = false;
 
 			// The target may become hidden between the initial order request and the first tick (e.g. if queued)
 			// Moving to any position (even if quite stale) is still better than immediately giving up
@@ -81,7 +82,7 @@ namespace OpenRA.Mods.Common.Activities
 
 		protected override void OnFirstRun(Actor self)
 		{
-			QueueChild(self, Mobile.MoveTo(() => CalculatePathToTarget(self)));
+			QueueChild(Mobile.MoveTo(() => CalculatePathToTarget(self)));
 		}
 
 		public override Activity Tick(Actor self)
@@ -116,7 +117,7 @@ namespace OpenRA.Mods.Common.Activities
 
 			// Target has moved, and MoveAdjacentTo is still valid.
 			if (!IsCanceling && shouldRepath)
-				QueueChild(self, Mobile.MoveTo(() => CalculatePathToTarget(self)));
+				QueueChild(Mobile.MoveTo(() => CalculatePathToTarget(self)));
 
 			ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
 			if (ChildActivity != null)

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

@@ -37,13 +37,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling || target.Type == TargetType.Invalid)
 				return NextActivity;
 
@@ -64,7 +57,7 @@ namespace OpenRA.Mods.Common.Activities
 			{
 				var turn = ActivityUtils.RunActivity(self, new Turn(self, facing));
 				if (turn != null)
-					QueueChild(self, turn);
+					QueueChild(turn);
 
 				return this;
 			}

OpenRA.Mods.Common/Activities/PickupUnit.cs

@@ -56,13 +56,6 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (cargo != carryall.Carryable)
 				return NextActivity;
 
@@ -86,7 +79,7 @@ namespace OpenRA.Mods.Common.Activities
 			switch (state)
 			{
 				case PickupState.Intercept:
-					QueueChild(self, movement.MoveWithinRange(Target.FromActor(cargo), WDist.FromCells(4), targetLineColor: Color.Yellow), true);
+					QueueChild(movement.MoveWithinRange(Target.FromActor(cargo), WDist.FromCells(4), targetLineColor: Color.Yellow));
 					state = PickupState.LockCarryable;
 					return this;
 
@@ -101,15 +94,15 @@ namespace OpenRA.Mods.Common.Activities
 				{
 					// Land at the target location
 					var localOffset = carryall.OffsetForCarryable(self, cargo).Rotate(carryableBody.QuantizeOrientation(self, cargo.Orientation));
-					QueueChild(self, new Land(self, Target.FromActor(cargo), -carryableBody.LocalToWorld(localOffset), carryableFacing.Facing), true);
+					QueueChild(new Land(self, Target.FromActor(cargo), -carryableBody.LocalToWorld(localOffset), carryableFacing.Facing));
 
 					// Pause briefly before attachment for visual effect
 					if (delay > 0)
-						QueueChild(self, new Wait(delay, false));
+						QueueChild(new Wait(delay, false));
 
 					// Remove our carryable from world
-					QueueChild(self, new CallFunc(() => Attach(self)));
+					QueueChild(new CallFunc(() => Attach(self)));
-					QueueChild(self, new TakeOff(self));
+					QueueChild(new TakeOff(self));
 					return this;
 				}
 			}

OpenRA.Mods.Common/Activities/Resupply.cs

@@ -75,19 +75,12 @@ namespace OpenRA.Mods.Common.Activities
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			// HACK: If the activity is cancelled while we're already resupplying (or about to start resupplying),
 			// move actor outside the resupplier footprint
 			// TODO: This check is nowhere near robust enough, and should be rewritten
 			if (IsCanceling && host.IsInRange(self.CenterPosition, closeEnough))
 			{
-				QueueChild(self, self.Trait<IMove>().MoveToTarget(self, host), true);
+				QueueChild(self.Trait<IMove>().MoveToTarget(self, host));
 				foreach (var notifyResupply in notifyResupplies)
 					notifyResupply.ResupplyTick(host.Actor, self, ResupplyType.None);
 

OpenRA.Mods.Common/Activities/Transform.cs

@@ -37,10 +37,10 @@ namespace OpenRA.Mods.Common.Activities
 		protected override void OnFirstRun(Actor self)
 		{
 			if (self.Info.HasTraitInfo<IFacingInfo>())
-				QueueChild(self, new Turn(self, Facing));
+				QueueChild(new Turn(self, Facing));
 
 			if (self.Info.HasTraitInfo<AircraftInfo>())
-				QueueChild(self, new Land(self));
+				QueueChild(new Land(self));
 		}
 
 		public override Activity Tick(Actor self)
@@ -48,12 +48,6 @@ namespace OpenRA.Mods.Common.Activities
 			if (IsCanceling)
 				return NextActivity;
 
-			if (ChildActivity != null)
-			{
-				ActivityUtils.RunActivity(self, ChildActivity);
-				return this;
-			}
-
 			// Prevent deployment in bogus locations
 			var transforms = self.TraitOrDefault<Transforms>();
 			if (transforms != null && !transforms.CanDeploy())
@@ -72,7 +66,7 @@ namespace OpenRA.Mods.Common.Activities
 				IsInterruptible = false;
 
 				// Wait forever
-				QueueChild(self, new WaitFor(() => false));
+				QueueChild(new WaitFor(() => false));
 				makeAnimation.Reverse(self, () => DoTransform(self));
 				return this;
 			}

OpenRA.Mods.Common/Activities/UnloadCargo.cs

@@ -77,27 +77,20 @@ namespace OpenRA.Mods.Common.Activities
 			if (aircraft != null)
 			{
 				// Queue the activity even if already landed in case self.Location != destination
-				QueueChild(self, new Land(self, destination, unloadRange));
+				QueueChild(new Land(self, destination, unloadRange));
 				takeOffAfterUnload = !aircraft.AtLandAltitude;
 			}
 			else
 			{
 				var cell = self.World.Map.Clamp(this.self.World.Map.CellContaining(destination.CenterPosition));
-				QueueChild(self, new Move(self, cell, unloadRange));
+				QueueChild(new Move(self, cell, unloadRange));
 			}
 
-			QueueChild(self, new Wait(cargo.Info.BeforeUnloadDelay));
+			QueueChild(new Wait(cargo.Info.BeforeUnloadDelay));
 		}
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (IsCanceling || cargo.IsEmpty(self))
 				return NextActivity;
 
@@ -113,7 +106,7 @@ namespace OpenRA.Mods.Common.Activities
 				if (exitSubCell == null)
 				{
 					self.NotifyBlocker(BlockedExitCells(actor));
-					QueueChild(self, new Wait(10), true);
+					QueueChild(new Wait(10));
 					return this;
 				}
 
@@ -138,10 +131,10 @@ namespace OpenRA.Mods.Common.Activities
 			{
 				Cancel(self, true);
 				if (cargo.Info.AfterUnloadDelay > 0)
-					QueueChild(self, new Wait(cargo.Info.AfterUnloadDelay, false), true);
+					QueueChild(new Wait(cargo.Info.AfterUnloadDelay, false));
 
 				if (takeOffAfterUnload)
-					QueueChild(self, new TakeOff(self), true);
+					QueueChild(new TakeOff(self));
 			}
 
 			return this;

OpenRA.Mods.Common/Activities/WaitForTransport.cs

@@ -11,7 +11,6 @@
 
 using OpenRA.Activities;
 using OpenRA.Mods.Common.Traits;
-using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Activities
 {
@@ -28,18 +27,11 @@ namespace OpenRA.Mods.Common.Activities
 
 		protected override void OnFirstRun(Actor self)
 		{
-			QueueChild(self, inner);
+			QueueChild(inner);
 		}
 
 		public override Activity Tick(Actor self)
 		{
-			if (ChildActivity != null)
-			{
-				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-				if (ChildActivity != null)
-					return this;
-			}
-
 			if (transportable != null)
 				transportable.MovementCancelled(self);
 

OpenRA.Mods.Common/Traits/Air/Aircraft.cs

@@ -861,7 +861,7 @@ namespace OpenRA.Mods.Common.Traits
 		public Activity VisualMove(Actor self, WPos fromPos, WPos toPos)
 		{
 			// TODO: Ignore repulsion when moving
-			return ActivityUtils.SequenceActivities(self,
+			return ActivityUtils.SequenceActivities(
 				new CallFunc(() => SetVisualPosition(self, fromPos)),
 				new Fly(self, Target.FromPos(toPos)));
 		}

OpenRA.Mods.Common/Traits/Attack/AttackFollow.cs

@@ -257,13 +257,6 @@ namespace OpenRA.Mods.Common.Traits
 
 			public override Activity Tick(Actor self)
 			{
-				if (ChildActivity != null)
-				{
-					ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
-					if (ChildActivity != null)
-						return this;
-				}
-
 				if (IsCanceling)
 				{
 					// Cancel the requested target, but keep firing on it while in range
@@ -362,7 +355,7 @@ namespace OpenRA.Mods.Common.Traits
 				}
 
 				wasMovingWithinRange = true;
-				QueueChild(self, move.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, Color.Red), true);
+				QueueChild(move.MoveWithinRange(target, minRange, maxRange, checkTarget.CenterPosition, Color.Red));
 				return this;
 			}
 

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

@@ -164,9 +164,9 @@ namespace OpenRA.Mods.Common.Traits
 		{
 			if (!preventDock)
 			{
-				dockOrder.QueueChild(self, new CallFunc(() => dockedHarv = harv, false));
+				dockOrder.QueueChild(new CallFunc(() => dockedHarv = harv, false));
-				dockOrder.QueueChild(self, DockSequence(harv, self));
+				dockOrder.QueueChild(DockSequence(harv, self));
-				dockOrder.QueueChild(self, new CallFunc(() => dockedHarv = null, false));
+				dockOrder.QueueChild(new CallFunc(() => dockedHarv = null, false));
 			}
 		}
 

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

@@ -130,7 +130,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (!order.Queued && activity.NextActivity != null)
 				activity.NextActivity.Cancel(self);
 
-			activity.Queue(self, new IssueOrderAfterTransform(order.OrderString, order.Target));
+			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target));
 
 			if (currentTransform == null)
 				self.QueueActivity(order.Queued, activity);

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

@@ -100,7 +100,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (!order.Queued && activity.NextActivity != null)
 				activity.NextActivity.Cancel(self);
 
-			activity.Queue(self, new IssueOrderAfterTransform(order.OrderString, order.Target));
+			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target));
 
 			if (currentTransform == null)
 				self.QueueActivity(order.Queued, activity);

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

@@ -111,7 +111,7 @@ namespace OpenRA.Mods.Common.Traits
 				if (!order.Queued && activity.NextActivity != null)
 					activity.NextActivity.Cancel(self);
 
-				activity.Queue(self, new IssueOrderAfterTransform("Move", order.Target));
+				activity.Queue(new IssueOrderAfterTransform("Move", order.Target));
 
 				if (currentTransform == null)
 					self.QueueActivity(order.Queued, activity);

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

@@ -124,7 +124,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (!order.Queued && activity.NextActivity != null)
 				activity.NextActivity.Cancel(self);
 
-			activity.Queue(self, new IssueOrderAfterTransform(order.OrderString, order.Target));
+			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target));
 
 			if (currentTransform == null)
 				self.QueueActivity(order.Queued, activity);

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

@@ -118,7 +118,7 @@ namespace OpenRA.Mods.Common.Traits
 			if (!order.Queued && activity.NextActivity != null)
 				activity.NextActivity.Cancel(self);
 
-			activity.Queue(self, new IssueOrderAfterTransform(order.OrderString, order.Target));
+			activity.Queue(new IssueOrderAfterTransform(order.OrderString, order.Target));
 
 			if (currentTransform == null)
 				self.QueueActivity(order.Queued, activity);

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

@@ -132,7 +132,7 @@ namespace OpenRA.Mods.Common.Traits
 				return moveInner;
 
 			var activity = new DeployForGrantedCondition(self, this, true);
-			activity.Queue(self, moveInner);
+			activity.Queue(moveInner);
 			return activity;
 		}
 

OpenRA.Mods.Common/Traits/Mobile.cs

@@ -322,7 +322,7 @@ namespace OpenRA.Mods.Common.Traits
 					var notifyBlocking = new CallFunc(() => self.NotifyBlocker(cellInfo.Cell));
 					var waitFor = new WaitFor(() => CanEnterCell(cellInfo.Cell));
 					var move = new Move(self, cellInfo.Cell);
-					self.QueueActivity(ActivityUtils.SequenceActivities(self, notifyBlocking, waitFor, move));
+					self.QueueActivity(ActivityUtils.SequenceActivities(notifyBlocking, waitFor, move));
 
 					Log.Write("debug", "OnNudge (notify next blocking actor, wait and move) #{0} from {1} to {2}",
 						self.ActorID, self.Location, cellInfo.Cell);
@@ -691,7 +691,7 @@ namespace OpenRA.Mods.Common.Traits
 
 			var delta = toPos - fromPos;
 			var facing = delta.HorizontalLengthSquared != 0 ? delta.Yaw.Facing : Facing;
-			return ActivityUtils.SequenceActivities(self, new Turn(self, facing), new Drag(self, fromPos, toPos, length));
+			return ActivityUtils.SequenceActivities(new Turn(self, facing), new Drag(self, fromPos, toPos, length));
 		}
 
 		CPos? ClosestGroundCell()

OpenRA.Mods.Common/Traits/Repairable.cs

@@ -124,7 +124,7 @@ namespace OpenRA.Mods.Common.Traits
 					self.CancelActivity();
 
 				self.SetTargetLine(order.Target, Color.Green);
-				var activities = ActivityUtils.SequenceActivities(self,
+				var activities = ActivityUtils.SequenceActivities(
 					movement.MoveToTarget(self, order.Target, targetLineColor: Color.Green),
 					new CallFunc(() => AfterReachActivities(self, order, movement)));