I am sure someone else must have already done this in Rust, but I thought it useful to post the code. The HList paper I wrote with Oleg Kiselyov and Ralf Lemmel in 2004 used a lot of techniques like that in Haskell to do some interesting stuff. There was a follow up paper in 2005 called OOHaskell that I also contributed to, which builds up OO language features from a sound type system base.