Remove AttackBase.IgnoresVisibility.

This was a workaround for D2K sandworms, which is
now implemented using a custom attack activity.

OpenRA.Mods.Common/UpdateRules/Rules/20180923/RemoveAttackIgnoresVisibility.cs

@@ -0,0 +1,66 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2018 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace OpenRA.Mods.Common.UpdateRules.Rules
+{
+	public class RemoveAttackIgnoresVisibility : UpdateRule
+	{
+		public override string Name { get { return "IgnoresVisibility has been removed from Attack* traits."; } }
+		public override string Description
+		{
+			get
+			{
+				return "The IgnoresVisibility flag has been removed from the Attack* traits as part of a\n" +
+				       "wider rework of the fog-targeting behaviour. Mods that rely on this logic must\n" +
+				       "implement their own Attack* trait, similar to the AttackSwallow trait.";
+			}
+		}
+
+		static readonly string[] Traits =
+		{
+			"AttackFrontal",
+			"AttackFollow",
+			"AttackTurreted",
+			"AttackOmni",
+			"AttackBomber",
+			"AttackPopupTurreted",
+			"AttackTesla",
+			"AttackSwallow"
+		};
+
+		readonly List<string> locations = new List<string>();
+
+		public override IEnumerable<string> AfterUpdate(ModData modData)
+		{
+			if (locations.Any())
+				yield return "The IgnoresVisibility flag has been removed from the targeting logic on the following actors:\n" +
+					UpdateUtils.FormatMessageList(locations) + "\n\n" +
+					"You may wish to enable TargetFrozenActors, or implement a custom Attack* trait like AttackSwallow\n" +
+					"if you require visibility to be completely ignored.";
+
+			locations.Clear();
+		}
+
+		public override IEnumerable<string> UpdateActorNode(ModData modData, MiniYamlNode actorNode)
+		{
+			foreach (var trait in Traits)
+				foreach (var t in actorNode.ChildrenMatching(trait))
+					if (t.RemoveNodes("IgnoresVisibility") > 0)
+						locations.Add("{0} ({1})".F(actorNode.Key, actorNode.Location.Filename));
+
+			yield break;
+		}
+	}
+}