Fix for an error about mergeables

Source/PerformanceFish/JobSystem/WorkGiver_MergeOptimization.cs

@@ -0,0 +1,28 @@
+// Copyright (c) 2022 bradson
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+namespace PerformanceFish.JobSystem;
+
+public class WorkGiver_MergeOptimization : ClassWithFishPatches
+{
+	public class JobOnThing_Patch : FishPatch
+	{
+		public override string Description => "Removes mergeables from ListerMergeables if they no longer qualify as mergeable when trying to check for a merging job on them. Vanilla RimWorld just fails and keeps them in";
+		public override MethodBase TargetMethodInfo => AccessTools.Method(typeof(WorkGiver_Merge), nameof(WorkGiver_Merge.JobOnThing));
+
+		public static void Prefix(Thing t)
+		{
+			if (t.GetSlotGroup() is null)
+				RemoveFromListerMergeables(t);
+		}
+
+		private static void RemoveFromListerMergeables(Thing t)
+		{
+			var map = t.MapHeld;
+			map.listerMergeables.TryRemove(t);
+			map.listerHaulables.Check(t);
+		}
+	}
+}