Hi, Am Mittwoch, den 30.11.2016, 10:51 +0000 schrieb Simon Peyton Jones via ghc-devs:
I very much doubt that you'll be able to discard the context information from the type checker. Maybe some of it. I can't say exactly why, it's a gut feel for now.
the gut feeling is warranted: There are quite a few errors that are raised directly by the type checker, and not expressed as a WantedConstraint that can be deferred. Kind errors inside types, for example. It might be an interesting exercise to try to make all errors deferrable somehow. With some additions to the relevant types (HsType etc.) this might work. But until then, a second pass would have to *duplicate* all the context-handling machinery, and that is surely not the way to go. Punting this for now, for want of a better idea. Greetings, Joachim -- Joachim “nomeata” Breitner mail@joachim-breitner.de • https://www.joachim-breitner.de/ XMPP: nomeata@joachim-breitner.de • OpenPGP-Key: 0xF0FBF51F Debian Developer: nomeata@debian.org