[GHC] #5863: Deriving Typeable for data families

[GHC]

#5863: Deriving Typeable for data families
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    Reporter:  simonpj           |       Owner:                  
        Type:  bug               |      Status:  new             
    Priority:  normal            |   Milestone:  7.6.2           
   Component:  Compiler          |     Version:  7.4.1           
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
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Comment(by dreixel):

 We do allow (standalone) `deriving Typeable` for `T`, so I guess the way
 to fix this is to simply disable `deriving Typeable` for family instances.
 Unless we want to wait for #7897, of course.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5863#comment:5>
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