[GHC] #9199: Wrong Template Haskell desugaring

12 Jun 2014


      #9199: Wrong Template Haskell desugaring
------------------------------------+-------------------------------------
       Reporter:  simonpj           |             Owner:
           Type:  bug               |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.8.2
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
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 This code
 {{{
 {-# LANGUAGE TemplateHaskell, PolyKinds, TypeFamilies #-}

 module T9160 where

 $( [d| class C (a :: k) where
           type F (a :: k) :: *
     |]
  )
 }}}
 yields
 {{{
 T9160.hs:5:4:
     Kind variable also used as type variable: ‘k_a2cl’
     In the declaration for class C_a2cj
 }}}
 which is utterly bogus.

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9199
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