presence of the trait is enough; don't need to check a legacy flag too.

OpenRa.Game/GameRules/UnitInfo.cs

@@ -68,7 +68,6 @@ namespace OpenRa.Game.GameRules
 
 	public class InfantryInfo : MobileInfo
 	{
-		public readonly bool Crushable = true; // also on VehicleInfo, but with a different default
 		public readonly bool C4 = false;
 		public readonly bool FraidyCat = false;
 		public readonly bool Infiltrate = false;
@@ -80,7 +79,6 @@ namespace OpenRa.Game.GameRules
 
 	public class VehicleInfo : MobileInfo
 	{
-		public readonly bool Crushable = false;
 		public readonly bool Tracked = false;
 
 		public VehicleInfo(string name) : base(name) { }

OpenRa.Game/OpenRa.Game.csproj

@@ -181,7 +181,7 @@
     <Compile Include="Traits\Fake.cs" />
     <Compile Include="Traits\Harvester.cs" />
     <Compile Include="Traits\Helicopter.cs" />
-    <Compile Include="Traits\Infantry.cs" />
+    <Compile Include="Traits\SquishByTank.cs" />
     <Compile Include="Traits\Plane.cs" />
     <Compile Include="Traits\ProductionQueue.cs" />
     <Compile Include="Traits\ProductionSurround.cs" />

OpenRa.Game/Traits/SquishByTank.cs

@@ -5,10 +5,10 @@ using OpenRa.Game.GameRules;
 
 namespace OpenRa.Game.Traits
 {
-	class Infantry : ICrushable
+	class SquishByTank : ICrushable
 	{
 		readonly Actor self;
-		public Infantry(Actor self)
+		public SquishByTank(Actor self)
 		{
 			this.self = self;
 		}
@@ -26,7 +26,6 @@ namespace OpenRa.Game.Traits
 		public bool IsCrushableBy(UnitMovementType umt, Player player)
 		{
 			if (player == Game.LocalPlayer) return false;
-			if (!(self.Info as InfantryInfo).Crushable) return false;
 			switch (umt)
 			{
 				case UnitMovementType.Track: return true;