Very presumptuous and egotistical to think this is about you. It's not about you, it's about the code that has been contributed which requires a separate line item and which you have contributed which you state is legally owned by someone else.
Maybe not personally -- clearly almost nobody gives a rat's ass about me, or about Haskell code in general for that matter -- but I'm just a little exasperated by being used as a proxy cudgel to wield against my totally reasonable employer, when the people who are sniping from the peanut gallery really have no idea what the legal situation is, what I have or haven't agreed to, whether I have done this voluntarily or under coercion, etc etc.
It is nice that there is some reasonable discussion coming out of this thread about the law and industry practices re: intellectual property vis-a-vis programmers, but for the most part I am pretty disappoint.
You previously said that you have to fill out paperwork in order to retain your copyright; that strongly implies that Google can deny your request. I suspect that you wouldn't be so understanding if it were Google claiming ownership of your startup instead.
The question remains: is this due to a law, or a contract that you've signed? What do other developers need to do in order to make sure that they can release their side project software under their own terms, without having to jump through bureaucratic hoops or needing permission from their employer.