[GHC] #5498: Generalized newtype deriving allows creating of instances I can't create by hand

[GHC]

#5498: Generalized newtype deriving allows creating of instances I can't create by
hand
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    Reporter:  dterei            |        Owner:              
        Type:  bug               |       Status:  new         
    Priority:  normal            |    Milestone:              
   Component:  Compiler          |      Version:  7.3         
    Keywords:                    |     Testcase:              
   Blockedby:                    |   Difficulty:              
          Os:  Unknown/Multiple  |     Blocking:              
Architecture:  Unknown/Multiple  |      Failure:  None/Unknown
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Comment(by simonpj):

 I really don't know of a "simple syntactic restriction" that would do the
 job.  And the "roles" paper requires thought about how to implement it.
 Definitely it must wait until the current stuff for kind inference is
 done.

 Is this really ruining anyone's day?

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5498#comment:4>
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