using System; using System.Collections; using System.Collections.Generic; class SystemTest : IEquatable, IComparer, IComparer, IComparable, IComparable { public override bool Equals(object other) { return Equals(this, other) || ReferenceEquals(this, other); } public override int GetHashCode() { return 1; } public bool Equals(SystemTest other) { return false; } public int Compare(object x, object y) { return 0; } public int Compare(SystemTest x, SystemTest y) { return 0; } int IComparable.CompareTo(object other) { return 0; } int IComparable.CompareTo(SystemTest other) { return 0; } }