[GHC] #8177: Roles for type families

[GHC]

#8177: Roles for type families
-------------------------------------+-------------------------------------
        Reporter:  simonpj           |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  ⊥
       Component:  Compiler          |              Version:  7.6.3
      Resolution:                    |             Keywords:  TypeFamilies
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3662
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by simonpj):

 > I've uploaded a rough attempt at implementing support for roles for
 closed type families

 Great work!  But I really would prefer to see a specification first :-).
 There's a lot of discussion on this thread about what the specification
 should even be.

 It's hard to review an implementation without a spec, covering
  * Syntax
  * Typing rules (at least in clear English)
  * Lots of examples

 Of course, we'd ultimately like a proof of soundness of the rules, but the
 "Richard thinks this is right" tests is at least a start.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8177#comment:36>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler