Bikeshedding request for GHCi's :type

Richard Eisenberg eir at
Tue Apr 26 13:08:27 UTC 2016

Hi devs,

Over the weekend, I was pondering the Haskell course I will be teaching next year and shuddered at having to teach Foldable at the same time as `length`. So I implemented feature request #10963 (, which allows for a way for a user to request a specialization of a type. It all works wonderfully, but there is a real user-facing design issue here around the default behavior of :type and whether or not to add new :type-y like commands. I have outlined the situation here:

I'd love some broad input on this issue. If you've got a stake in how this all works, please skim that wiki page and comment on #10963.


More information about the ghc-devs mailing list