I'm also not a lawyer, I can indeed see it being prudent to not go looking at code you're not legally allowed to use related to what you're working on right now

I'm also not a lawyer, I can indeed see it being prudent to not go looking at code you're not legally allowed to use related to what you're working on right now (I wouldn't do that). But I can't believe looking at any other code in general would "taint" you in some way. And yes, clean room design is a bit more extreme in that regard (which is probably something companies/individuals do if they expect a high risk of litigation, as it probably makes it a lot easier to prove that there is no copyright infringement, and certainly not willful infringement) So, the requirement for Wine and ReactOS mentioned in the other comments is probably not unreasonable.