[GHC] #8813: further support deriving instances Typeable1, Typeable2, etc

[GHC]

#8813: further support deriving instances Typeable1, Typeable2, etc
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        Reporter:  maeder                     |            Owner:
            Type:  task                       |           Status:  closed
        Priority:  normal                     |        Milestone:
       Component:  Compiler                   |          Version:
      Resolution:  wontfix                    |  7.8.1-rc1
Operating System:  Unknown/Multiple           |         Keywords:
 Type of failure:  GHC rejects valid program  |     Architecture:
       Test Case:                             |  Unknown/Multiple
        Blocking:                             |       Difficulty:  Unknown
                                              |       Blocked By:
                                              |  Related Tickets:
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Comment (by carter):

 @maeder

 1) this ticket is closed

 2) if you're having trouble understanding how to work around this, please
 email haskell-cafe with questions, or ask for help on #haskell on freenode

 3) you can use CPP + Reid's suggestion of constraint kinds (http://blog
 .omega-prime.co.uk/?p=127 is a blog post on them) to emulate having
 Typeable1 ... N conditionally defined as non polykinded alternatives using
 constraint kinds. This seems to be more work than just fixing the code
 mind you :)

 4) if you're confused about constraint kinds, ask on haskell cafe mailing
 list or on #haskell on freenode

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8813#comment:13>
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