[GHC] #7704: Phantom types break new polykind Typeable with either StandaloneDeriving or AutoDeriveTypeable

[GHC]

#7704: Phantom types break new polykind Typeable with either StandaloneDeriving or
AutoDeriveTypeable
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Reporter:  nwf               |          Owner:  dreixel         
    Type:  bug               |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  7.7               |       Keywords:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
 Failure:  None/Unknown      |      Blockedby:                  
Blocking:                    |        Related:                  
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Comment(by monoidal):

 In fact the "deriving (Typeable)" clause does not work either:

 {{{
 {-# LANGUAGE DeriveDataTypeable, PolyKinds #-}

 import Data.Typeable

 newtype Tagged s b = Tagged { unTagged :: b } deriving (Typeable)

 k :: Typeable u => u -> Int
 k _ = 0

 m = k (Tagged 0 :: Tagged Int Int)
 }}}

 (The code compiles without PolyKinds.)

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7704#comment:4>
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