Add Locomotor lint check

OpenRA.Game/Traits/LintAttributes.cs

@@ -34,6 +34,9 @@ namespace OpenRA.Traits
 	[AttributeUsage(AttributeTargets.Field)]
 	public sealed class VoiceReferenceAttribute : Attribute { }
 
+	[AttributeUsage(AttributeTargets.Field)]
+	public sealed class LocomotorReferenceAttribute : Attribute { }
+
 	[AttributeUsage(AttributeTargets.Field)]
 	public sealed class SequenceReferenceAttribute : Attribute
 	{

OpenRA.Mods.Common/Lint/CheckLocomotorReferences.cs

@@ -0,0 +1,51 @@
+#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.Linq;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Lint
+{
+	public class CheckLocomotorReferences : ILintRulesPass
+	{
+		public void Run(Action<string> emitError, Action<string> emitWarning, Ruleset rules)
+		{
+			var worldActor = rules.Actors["world"];
+			var locomotorInfos = worldActor.TraitInfos<LocomotorInfo>().ToArray();
+			foreach (var actorInfo in rules.Actors)
+			{
+				foreach (var traitInfo in actorInfo.Value.TraitInfos<ITraitInfo>())
+				{
+					var fields = traitInfo.GetType().GetFields().Where(f => f.HasAttribute<LocomotorReferenceAttribute>());
+					foreach (var field in fields)
+					{
+						var locomotors = LintExts.GetFieldValues(traitInfo, field, emitError);
+						foreach (var locomotor in locomotors)
+						{
+							if (string.IsNullOrEmpty(locomotor))
+								continue;
+
+							CheckLocomotors(actorInfo.Value, emitError, rules, locomotorInfos, locomotor);
+						}
+					}
+				}
+			}
+		}
+
+		void CheckLocomotors(ActorInfo actorInfo, Action<string> emitError, Ruleset rules, LocomotorInfo[] locomotorInfos, string locomotor)
+		{
+			if (!locomotorInfos.Any(l => l.Name == locomotor))
+				emitError("Actor {0} defines Locomotor {1} not found on World actor.".F(actorInfo.Name, locomotor));
+		}
+	}
+}

OpenRA.Mods.Common/Traits/Mobile.cs

@@ -27,7 +27,7 @@ namespace OpenRA.Mods.Common.Traits
 		UsesInit<FacingInit>, UsesInit<LocationInit>, UsesInit<SubCellInit>, IActorPreviewInitInfo
 	{
 		[Desc("Which Locomotor does this trait use. Must be defined on the World actor.")]
-		[FieldLoader.Require]
+		[LocomotorReference, FieldLoader.Require]
 		public readonly string Locomotor = null;
 
 		public readonly int InitialFacing = 0;