Updated reference and cleanup.

Author: electricessence

IChild.cs

@@ -1,7 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
-using System.Diagnostics.Contracts;
 
 namespace Open.Hierarchy
 {
@@ -22,7 +20,6 @@ public interface IChild<out TParent> : IChild
 		new TParent? Parent { get; }
 	}
 
-	[System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "Null check properly implemented.")]
 	public static class ChildExtensions
 	{
 		/// <summary>

Node.cs

@@ -21,9 +21,8 @@ public sealed partial class Node<T> : INode<Node<T>>, IElement<T>
 		IReadOnlyList<object> IParent.Children => EnsureChildrenMapped();
 		#endregion
 
-#pragma warning disable IDE0044 // Add readonly modifier
 		private bool _recycled;
-#pragma warning restore IDE0044 // Add readonly modifier
+
 		void AssertNotRecycled()
 		{
 			if (_recycled)

Open.Hierarchy.csproj

@@ -4,6 +4,7 @@
 		<TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
 		<LangVersion>latest</LangVersion>
 		<Nullable>enable</Nullable>
+		<EnableNETAnalyzers>true</EnableNETAnalyzers>
 		<GeneratePackageOnBuild>True</GeneratePackageOnBuild>
 		<Authors>electricessence</Authors>
 		<Description>
@@ -40,7 +41,7 @@
 	</ItemGroup>
 
 	<ItemGroup>
-		<PackageReference Include="Open.Disposable.ObjectPools" Version="2.5.0" />
+		<PackageReference Include="Open.Disposable.ObjectPools" Version="2.6.0" />
 	</ItemGroup>
 
 </Project>

TraversalExtensions.cs

@@ -19,7 +19,7 @@ public static IEnumerable<TNode> GetDescendantsOfType<TNode>(
 		{
 			foreach (var descendant in root.GetDescendants(traversal))
 			{
-				if (!(descendant is TNode n))
+				if (descendant is not TNode n)
 					throw new InvalidCastException(
 						"Descendant is not of expected generic type and may create inconsistent results.  May need to use non-generic node.GetDescenants method.");