f8ed97ecc1
Make elaboration generic over input Combines all the `elaborate_*` family of functions into just one, which is an iterator over the same type that you pass in (e.g. elaborating `Predicate` gives `Predicate`s, elaborating `Obligation`s gives `Obligation`s, etc.)
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.