[Haskell-cafe] Proof of concept of explanations for instance resolution

[Tom Ellis]

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