Hi all, I posted the below to ghc-devs, but they suggested perhaps Haskell-Cafe might be interested in the problem. For convenience, here's the ghc-devs archive of that discussion: https://mail.haskell.org/pipermail/ghc-devs/2016-October/013085.html ---------- Forwarded message ---------- From: Christopher Done <chrisdone@gmail.com> Date: 19 October 2016 at 12:45 Subject: How to best display type variables with the same name To: "ghc-devs@haskell.org" <ghc-devs@haskell.org> We've encountered a problem in Intero which is that when inspecting types of expressions and patterns, sometimes it happens that the type, when pretty printing, yields variables of the same name but which have different provenance. Here's a summary of the issue: https://github.com/commercialhaskell/intero/issues/280#issuecomment-25478490... And a strawman proposal of how it could be solved: https://github.com/commercialhaskell/intero/issues/280#issuecomment-25478792... What do you think? Also, if I were to implement the strawman proposal, is it possible to recover from a `tyvar :: Type` its original quantification/its "forall"? I've had a look through the API briefly and it looks like a _maybe_. Ciao!