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mikeizbicki / subhask

Type safe interface for working in subcategories of Hask
BSD 3-Clause "New" or "Revised" License
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Re-evaluate "limitations" now that GHC 8 is out #36

Open rpglover64 opened 8 years ago

rpglover64 commented 8 years ago

(I'm filing this just so that there is an issue, not because I expect it to be fixed any time soon)

Two of the points in the "Limitations" section refer to now-closed bugs with extensions available in GHC 8: UndecidableSuperClasses and TypeFamilyDependencies.

mikeizbicki commented 8 years ago

Thanks for filing the issue.

  1. The UndecidableSuperClasses is exactly what I wanted, and I'm in the process of roling that out.
  2. The TypeFamilyDependencies extension is extremely limited in the injectivity that is supported. I don't think this extension solves any of the problems that I was running into.
rpglover64 commented 8 years ago

Are there trac tickets for the problems it doesn't solve? I'm curious.

mikeizbicki commented 8 years ago

Here's an example: https://ghc.haskell.org/trac/ghc/ticket/12114

More generally, I need what this page describes as "Type C injectivity". Since types A and B aren't fully implemented yet, however, this seems like it's probably a long way off.