NUnit4002 shuoldn't trigger for `T` vs `nullable<T>` struct types

[MaceWindu]

class SomeType
{
    public Guid? Id { get; set; }
}

// proper assert : id != guid.empty
Assert.That(obj.Id, Is.Not.EqualTo(default(Guid)));

// suggested incorrect assert : Id != null
Assert.That(obj.Id, Is.Not.Default);