Both tests don't work. When a struct is turned into a class, they start to work

CodeCopPossibleBug.cs

using System;
using CodeCop.Core;
using CodeCop.Core.Fluent;
using NUnit.Framework;

namespace CodeCop.Tests
{
    public class CodeCopStructBugTests
    {
        public unsafe struct WithPtr
        {
            private readonly long* _ptr;

            public WithPtr(long* ptr)
            {
                _ptr = ptr;
            }

            public long Read()
            {
                return *_ptr;
            }
        }

        private long _return;

        public CodeCopStructBugTests()
        {
            Cop.AsFluent();

            typeof(WithPtr).GetMethod("Read").Override(c =>
            {
                // is this a problem? How is Sender passed for structs? Is it captured elsewhere, outside of the stack?
                Console.WriteLine(c.Sender);
                return _return;
            });

            Cop.Intercept();
        }

        [Test]
        public unsafe void When_intercepting_a_struct_with_invalid_pointer()
        {
            const long @return = 43509847534;
            _return = @return;
            var withPtr = new WithPtr((long*)new IntPtr(3));
            Assert.AreEqual(@return, withPtr.Read());
        }

        [Test]
        public unsafe void When_intercepting_a_struct_with_valid_pointer()
        {
            const long @return = 9873453;

            long l = 0;
            _return = @return;
            var withPtr = new WithPtr(&l);
            Assert.AreEqual(@return, withPtr.Read());
        }
    }
}