Implement extension.

Assets/Cryville/Crtr/Extension/RefTypes.cs

@@ -0,0 +1,60 @@
+using System.Collections.Generic;
+using System.Linq;
+using UnityEngine.Scripting;
+
+namespace Cryville.Crtr.Extension {
+	[Preserve]
+	public static class RefTypes {
+		[Preserve]
+		public static void PreserveEnumerable() {
+			IEnumerable<object> p = Enumerable.Empty<object>();
+			p.All(i => false);
+			p.Any();
+			p.Any(i => false);
+			p.Cast<object>();
+			p.Concat(Enumerable.Empty<object>());
+			p.Contains(null);
+			p.Count();
+			p.Count(i => false);
+			p.DefaultIfEmpty();
+			p.DefaultIfEmpty(null);
+			p.Distinct();
+			p.ElementAt(0);
+			p.ElementAtOrDefault(0);
+			p.First();
+			p.First(i => false);
+			p.FirstOrDefault();
+			p.FirstOrDefault(i => false);
+			p.GetEnumerator();
+			p.Last();
+			p.Last(i => false);
+			p.LastOrDefault();
+			p.LastOrDefault(i => false);
+			p.LongCount();
+			p.LongCount(i => false);
+			p.OrderBy(i => i).ThenBy(i => i);
+			p.OrderByDescending(i => i).ThenByDescending(i => i);
+			p.Reverse();
+			p.Select(i => i);
+			p.Select((i, j) => false);
+			p.SequenceEqual(p);
+			p.Single();
+			p.Single(i => false);
+			p.SingleOrDefault();
+			p.SingleOrDefault(i => false);
+			p.Skip(0);
+			p.SkipLast(0);
+			p.SkipWhile(i => false);
+			p.SkipWhile((i, j) => false);
+			p.Take(0);
+			p.TakeLast(0);
+			p.TakeWhile(i => false);
+			p.TakeWhile((i, j) => false);
+			p.ToArray();
+			p.ToHashSet();
+			p.ToList();
+			p.Where(i => false);
+			p.Where((i, j) => false);
+		}
+	}
+}

Assets/Cryville/Crtr/Extension/RefTypes.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 29a6376ce10b77e4099d2613876f9549
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: