This was a little experiment in capturing JSON serialization logic at the type-level.
Why tf would you want to do that? I hear you ask.
Well suppose you were writing a nice REST API. If you were going ham you probably want some nice swagger/OpenAPI docs, JSON schemas, generated typescript types and/or client code, etc etc.
All of these things depend on the details of your Aeson.ToJSON and Aeson.FromJSON instances.
Sure, you could keep these things in sync manually (and tbh, in the interest of simplicity, you probably should). But what if we could have GHC do it for us...
See here for what this might look like.
Disclaimer: This is a work in progress but there's very little work and it's not really in progress