Stabilize RimWorld 1.6 caches and tick optimizations

Source/PerformanceFish/System/ReflectionCaching.cs

@@ -535,6 +535,13 @@ public sealed class ReflectionCaching : ClassWithFishPatches
 			public static bool Prefix(ICustomAttributeProvider obj, Type attributeType, bool inherit,
 				out object[]? __result, out CustomAttributeState __state)
 			{
+				if (obj is null || attributeType is null)
+				{
+					__state = default;
+					__result = null;
+					return true;
+				}
+
 				var key = new CustomAttributeCache(obj, attributeType.TypeHandle, inherit);
 				__state = new() { Key = key };
 
@@ -656,7 +663,9 @@ public sealed class ReflectionCaching : ClassWithFishPatches
 			{
 				var value = new CustomAttributeCacheValue
 				{
-					Attributes = CopyCachedAttributes(result),
+					Attributes = result.Length == 0
+						? (object[])Array.CreateInstance(Type.GetTypeFromHandle(key.Second), 0)
+						: CopyCachedAttributes(result),
 					Status = CustomAttributeCacheStatus.Completed
 				};
 
@@ -693,7 +702,7 @@ public sealed class ReflectionCaching : ClassWithFishPatches
 
 			[MethodImpl(MethodImplOptions.AggressiveInlining)]
 			private static object[] CopyCachedAttributes(object[] attributes)
-				=> attributes.Length != 0 ? (object[])attributes.Clone() : Array.Empty<object>();
+				=> attributes.Length != 0 ? (object[])attributes.Clone() : attributes;
 
 			private static object _lock = new();
 		}
@@ -1024,8 +1033,6 @@ public sealed class ReflectionCaching : ClassWithFishPatches
 			[MethodImpl(MethodImplOptions.AggressiveInlining)]
 			public static bool Prefix(FieldInfo __instance, object? obj, ref object? __result)
 			{
-				ValidateGetValueCall(__instance, obj);
-
 				ref var cache = ref FieldGetters.GetOrAddReference(__instance.FieldHandle);
 
 				if (cache.Dirty
@@ -1035,6 +1042,8 @@ public sealed class ReflectionCaching : ClassWithFishPatches
 					return true;
 				}
 
+				// Unsupported fields fall back to Mono's implementation, including its exception behavior.
+				ValidateGetValueCall(__instance, obj);
 				__result = cache.Result!(obj);
 				return false;
 			}