mongodb/mongo-csharp-driver — comment on commit 4c1b6d2a80cf1b9b87157b9d758ebe63d864b9ef
File:  line 0
By craiggwilson:

Yeah, I started there but that ended up being a fruitless endeavor. Once you start doing anything with expression tree manipulation, you're heavily into reflection. So, I'd go down the simplest path possible to make your like easier.