diff --git a/OpenRA.Game/Traits/World/ActorMap.cs b/OpenRA.Game/Traits/World/ActorMap.cs
index b90a987052..f6b8dc4a1d 100644
--- a/OpenRA.Game/Traits/World/ActorMap.cs
+++ b/OpenRA.Game/Traits/World/ActorMap.cs
@@ -212,35 +212,36 @@ namespace OpenRA.Traits
 					yield return i.Actor;
 		}
 
-		public bool HasFreeSubCell(CPos a, bool checkTransient = true)
+		public bool HasFreeSubCell(CPos cell, bool checkTransient = true)
 		{
-			return FreeSubCell(a, SubCell.Any, checkTransient) != SubCell.Invalid;
+			return FreeSubCell(cell, SubCell.Any, checkTransient) != SubCell.Invalid;
 		}
 
-		public SubCell FreeSubCell(CPos a, SubCell preferredSubCell = SubCell.Any, bool checkTransient = true)
+		public SubCell FreeSubCell(CPos cell, SubCell preferredSubCell = SubCell.Any, bool checkTransient = true)
 		{
-			if (preferredSubCell > SubCell.Any && !AnyUnitsAt(a, preferredSubCell, checkTransient))
+			if (preferredSubCell > SubCell.Any && !AnyUnitsAt(cell, preferredSubCell, checkTransient))
 				return preferredSubCell;
 
-			if (!AnyUnitsAt(a))
+			if (!AnyUnitsAt(cell))
 				return map.DefaultSubCell;
 
 			for (var i = (int)SubCell.First; i < map.SubCellOffsets.Length; i++)
-				if (i != (int)preferredSubCell && !AnyUnitsAt(a, (SubCell)i, checkTransient))
+				if (i != (int)preferredSubCell && !AnyUnitsAt(cell, (SubCell)i, checkTransient))
 					return (SubCell)i;
+
 			return SubCell.Invalid;
 		}
 
-		public SubCell FreeSubCell(CPos a, SubCell preferredSubCell, Func<Actor, bool> checkIfBlocker)
+		public SubCell FreeSubCell(CPos cell, SubCell preferredSubCell, Func<Actor, bool> checkIfBlocker)
 		{
-			if (preferredSubCell > SubCell.Any && !AnyUnitsAt(a, preferredSubCell, checkIfBlocker))
+			if (preferredSubCell > SubCell.Any && !AnyUnitsAt(cell, preferredSubCell, checkIfBlocker))
 				return preferredSubCell;
 
-			if (!AnyUnitsAt(a))
+			if (!AnyUnitsAt(cell))
 				return map.DefaultSubCell;
 
 			for (var i = (int)SubCell.First; i < map.SubCellOffsets.Length; i++)
-				if (i != (int)preferredSubCell && !AnyUnitsAt(a, (SubCell)i, checkIfBlocker))
+				if (i != (int)preferredSubCell && !AnyUnitsAt(cell, (SubCell)i, checkIfBlocker))
 					return (SubCell)i;
 			return SubCell.Invalid;
 		}
@@ -325,7 +326,7 @@ namespace OpenRA.Traits
 			}
 		}
 
-		void RemoveInfluenceInner(ref InfluenceNode influenceNode, Actor toRemove)
+		static void RemoveInfluenceInner(ref InfluenceNode influenceNode, Actor toRemove)
 		{
 			if (influenceNode == null)
 				return;
diff --git a/OpenRA.Game/WPos.cs b/OpenRA.Game/WPos.cs
index 024e6ab4df..c1dfc4babc 100644
--- a/OpenRA.Game/WPos.cs
+++ b/OpenRA.Game/WPos.cs
@@ -35,6 +35,9 @@ namespace OpenRA
 		public static bool operator ==(WPos me, WPos other) { return me.X == other.X && me.Y == other.Y && me.Z == other.Z; }
 		public static bool operator !=(WPos me, WPos other) { return !(me == other); }
 
+		/// <summary>
+		/// Returns the linear interpolation between points 'a' and 'b'
+		/// </summary>
 		public static WPos Lerp(WPos a, WPos b, int mul, int div) { return a + (b - a) * mul / div; }
 
 		public static WPos LerpQuadratic(WPos a, WPos b, WAngle pitch, int mul, int div)
diff --git a/OpenRA.Mods.Common/Pathfinder/BasePathSearch.cs b/OpenRA.Mods.Common/Pathfinder/BasePathSearch.cs
index 981eb065a4..57fb3c3cad 100644
--- a/OpenRA.Mods.Common/Pathfinder/BasePathSearch.cs
+++ b/OpenRA.Mods.Common/Pathfinder/BasePathSearch.cs
@@ -81,7 +81,7 @@ namespace OpenRA.Mods.Common.Pathfinder
 				if (string.IsNullOrEmpty(id))
 				{
 					var builder = new StringBuilder();
-					builder.Append(this.Graph.Actor.ActorID);
+					builder.Append(Graph.Actor.ActorID);
 					while (!startPoints.Empty)
 					{
 						var startpoint = startPoints.Pop();
diff --git a/OpenRA.Mods.Common/Pathfinder/CellInfoLayerManager.cs b/OpenRA.Mods.Common/Pathfinder/CellInfoLayerManager.cs
index 5badfe959e..a78a783cf1 100644
--- a/OpenRA.Mods.Common/Pathfinder/CellInfoLayerManager.cs
+++ b/OpenRA.Mods.Common/Pathfinder/CellInfoLayerManager.cs
@@ -97,7 +97,7 @@ namespace OpenRA.Mods.Common.Pathfinder
 				{
 					defaultCellInfoLayer =
 						CellLayer<CellInfo>.CreateInstance(
-							mpos => new CellInfo(int.MaxValue, int.MaxValue, mpos.ToCPos(map as Map), CellStatus.Unvisited),
+							mpos => new CellInfo(int.MaxValue, int.MaxValue, mpos.ToCPos(map), CellStatus.Unvisited),
 							new Size(map.MapSize.X, map.MapSize.Y),
 							map.TileShape);
 				}
diff --git a/OpenRA.Mods.Common/Pathfinder/PathGraph.cs b/OpenRA.Mods.Common/Pathfinder/PathGraph.cs
index a84c542121..4336184890 100644
--- a/OpenRA.Mods.Common/Pathfinder/PathGraph.cs
+++ b/OpenRA.Mods.Common/Pathfinder/PathGraph.cs
@@ -73,8 +73,6 @@ namespace OpenRA.Mods.Common.Pathfinder
 		readonly MobileInfo mobileInfo;
 		CellLayer<CellInfo> cellInfo;
 
-		public const int InvalidNode = int.MaxValue;
-
 		public PathGraph(CellLayer<CellInfo> cellInfo, MobileInfo mobileInfo, Actor actor, World world, bool checkForBlocked)
 		{
 			this.cellInfo = cellInfo;
@@ -127,11 +125,11 @@ namespace OpenRA.Mods.Common.Pathfinder
 		{
 			int movementCost;
 			if (mobileInfo.CanEnterCell(
-				World as World,
-				Actor as Actor,
+				World,
+				Actor,
 				destNode,
 				out movementCost,
-				IgnoredActor as Actor,
+				IgnoredActor,
 				checkConditions) && !(CustomBlock != null && CustomBlock(destNode)))
 			{
 				return CalculateCellCost(destNode, direction, movementCost);
diff --git a/OpenRA.Mods.Common/Traits/World/PathFinder.cs b/OpenRA.Mods.Common/Traits/World/PathFinder.cs
index 25d96aea35..70e71fcfc6 100644
--- a/OpenRA.Mods.Common/Traits/World/PathFinder.cs
+++ b/OpenRA.Mods.Common/Traits/World/PathFinder.cs
@@ -93,7 +93,7 @@ namespace OpenRA.Mods.Common.Traits
 			// This assumes that the SubCell does not change during the path traversal
 			var tilesInRange = world.Map.FindTilesInCircle(targetCell, range.Length / 1024 + 1)
 				.Where(t => (world.Map.CenterOfCell(t) - target).LengthSquared <= range.LengthSquared
-							&& mi.CanEnterCell(self.World as World, self as Actor, t));
+							&& mi.CanEnterCell(self.World, self, t));
 
 			// See if there is any cell within range that does not involve a cross-domain request
 			// Really, we only need to check the circle perimeter, but it's not clear that would be a performance win