diff --git a/OpenRA.Game/Traits/TraitsInterfaces.cs b/OpenRA.Game/Traits/TraitsInterfaces.cs
index 7d3d622c95..66feb9aa24 100644
--- a/OpenRA.Game/Traits/TraitsInterfaces.cs
+++ b/OpenRA.Game/Traits/TraitsInterfaces.cs
@@ -66,20 +66,6 @@ namespace OpenRA.Traits
 		}
 	}
 
-	[Flags]
-	public enum ImpactType
-	{
-		None = 0,
-		Ground = 1,
-		GroundHit = 2,
-		Water = 4,
-		WaterHit = 8,
-		Air = 16,
-		AirHit = 32,
-		TargetTerrain = 64,
-		TargetHit = 128
-	}
-
 	public class AttackInfo
 	{
 		public Damage Damage;
diff --git a/OpenRA.Mods.Common/Warheads/Warhead.cs b/OpenRA.Mods.Common/Warheads/Warhead.cs
index 03ef1c7a97..19e8e24069 100644
--- a/OpenRA.Mods.Common/Warheads/Warhead.cs
+++ b/OpenRA.Mods.Common/Warheads/Warhead.cs
@@ -9,12 +9,27 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Drawing;
 using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Warheads
 {
+	[Flags]
+	public enum ImpactType
+	{
+		None = 0,
+		Ground = 1,
+		GroundHit = 2,
+		Water = 4,
+		WaterHit = 8,
+		Air = 16,
+		AirHit = 32,
+		TargetTerrain = 64,
+		TargetHit = 128
+	}
+
 	[Desc("Base warhead class. This can be used to derive other warheads from.")]
 	public abstract class Warhead : IWarhead
 	{
@@ -32,6 +47,7 @@ namespace OpenRA.Mods.Common.Warheads
 
 		[Desc("Delay in ticks before applying the warhead effect.", "0 = instant (old model).")]
 		public readonly int Delay = 0;
+
 		int IWarhead.Delay { get { return Delay; } }
 
 		[Desc("The color used for this warhead's visualization in the world's `WarheadDebugOverlay` trait.")]