On Wed, Oct 26, 2016 at 05:53:31PM -0700, Michael Sloan wrote:
When typeclass machinery gets complicated, it can be hard to figure interpret the meaning behind GHC's messages. In particular "Could not deduce ..." messages often reference constraints that are deep in a tree of resolving typeclasses. I think it would be great if GHC provided additional information for this circumstance. In a way what we need is a "stack trace" of what GHC was thinking about when yielding these type errors. [...] Thanks for reading! I hope we can address this UI concern in the future. I hope I've contributed something by demonstrating the possibility!
I think a "stack trace" of what GHC was thinking would be a great idea! I brought this idea here: https://mail.haskell.org/pipermail/haskell-cafe/2016-August/124622.html Tom