Comparison to null object in query throws exception

[nirinchev]

The following unit test fails with Data Type mismatch error:

[Test]
public void CheckObjectToNullComparison()
{
    _realm.Write(() =>
    {
        _realm.Add(new Owner
        {
            Name = "Ivar the Dogless"
        });
    });

    var result = _realm.All<Owner>()
                        .Where(x => x.TopDog == null)
                        .ToArray();
}