Problem with filtering nested object properties

[illunix]

If I try filter any other property that is not from nested object it works, but if try filter nested object property it does not idk why

[lukaszkepa]

I think it's because of the null check which is added here: https://github.com/Biarity/Sieve/blob/master/Sieve/Services/SieveProcessor.cs#L296
In this case .Where(u => new User { FirstName = ..., LastName = ... } != null) cannot be translated to SQL. I'm struggling with the same issue.