gistfile1.cs

        [TestMethod]
        public void TestSelfRecursion()
        {
            var original = new Recursive();
            original.Recursion = original;
            var clone = original.Copy();
            Assert.IsFalse(ReferenceEquals(original, clone));
            Assert.IsFalse(ReferenceEquals(original.Recursion, clone.Recursion));

            Assert.IsTrue(ReferenceEquals(original, original.Recursion));
            Assert.IsTrue(ReferenceEquals(clone, clone.Recursion));
        }

        [TestMethod]
        public void TestSelfRecursionOverrideHash()
        {
            var original = new RecursiveOverrideHash();
            original.Recursion = original;
            var clone = original.Copy();
            Assert.IsFalse(ReferenceEquals(original, clone));
            Assert.IsFalse(ReferenceEquals(original.Recursion, clone.Recursion));

            Assert.IsTrue(ReferenceEquals(original, original.Recursion));
            Assert.IsTrue(ReferenceEquals(clone, clone.Recursion));
        }
        
                public class Recursive
        {
            public Recursive Recursion;
        }
        public class RecursiveOverrideHash
        {
            private static Int32 counter=1;
            public RecursiveOverrideHash Recursion;
            public override int GetHashCode()
            {
                return ++counter;
            }
        }

StackOverflow exception when GetHashCode overridden