public class C
{
    public int Id { get; set; }
    public int I { get; set; }
}

[Fact]
public void Convert_to_BsonValue_should_work()
{
    var client = DriverTestConfiguration.Linq3Client;
    var database = client.GetDatabase("test");
    var collection = database.GetCollection<C>("test");    

    var queryable = collection.AsQueryable().Select(x => new { V = (BsonValue)x.I });    

    var pipeline = queryable.ToString();
}