public class TestEntity : Entity
    {
    }    public static class MongoBugs
    {
        [Fact]
        public static void TestMongoIQueryableBug()
        {
            var mongoDb = new MongoClient(new MongoClientSettings
            {
                ServerSelectionTimeout = TimeSpan.FromMilliseconds(0)
            }).GetDatabase("admin");
            var expression = CreateGuidFilterExpression(nameof(TestEntity.Id), Guid.Empty);
            try
            {
                mongoDb.GetCollection<TestEntity>(nameof(TestEntity)).AsQueryable().Where(expression).First();
            }
            catch (Exception ex)
            {
                ex.Should().BeAssignableTo<ArgumentNullException>();
            }
        }        

private static Expression<Func<TestEntity, bool>> CreateGuidFilterExpression(string propertyName,
            Guid value)
        {
            // expression input parameter
            var entityParameter = Expression.Parameter(typeof(TestEntity));
            return
                // parameter.[propertyName] == .Constant(value) expression
                Expression.Lambda<Func<TestEntity, bool>>(
                    Expression.Equal(Expression.Property(entityParameter, propertyName),
                        Expression.Constant(value)),
                    entityParameter);
        }
    }

var entityParameter = Expression.Parameter(typeof(TestEntity), "entity");