Check for dead actors when searching for exits.

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

@@ -35,12 +35,12 @@ namespace OpenRA.Mods.Common.Traits
 		[Desc("Exits with larger priorities will be used before lower priorities.")]
 		public readonly int Priority = 1;
 
-		public override object Create(ActorInitializer init) { return new Exit(init, this); }
+		public override object Create(ActorInitializer init) { return new Exit(this); }
 	}
 
 	public class Exit : ConditionalTrait<ExitInfo>
 	{
-		public Exit(ActorInitializer init, ExitInfo info)
+		public Exit(ExitInfo info)
 			: base(info) { }
 	}
 
@@ -62,6 +62,9 @@ namespace OpenRA.Mods.Common.Traits
 
 		public static IEnumerable<Exit> Exits(this Actor actor, string productionType = null)
 		{
+			if (!actor.IsInWorld || actor.Disposed)
+				return Enumerable.Empty<Exit>();
+
 			var all = actor.TraitsImplementing<Exit>()
 				.Where(Exts.IsTraitEnabled);
 
@@ -73,6 +76,9 @@ namespace OpenRA.Mods.Common.Traits
 
 		public static Exit RandomExitOrDefault(this Actor actor, World world, string productionType, Func<Exit, bool> p = null)
 		{
+			if (!actor.IsInWorld || actor.Disposed)
+				return null;
+
 			var allOfType = Exits(actor, productionType);
 			if (!allOfType.Any())
 				return null;