[GHC] #819: Uncaught kind error leads to the 'impossible' happening

[GHC]

#819: Uncaught kind error leads to the 'impossible' happening
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    Reporter:  sweirich at cis.upenn.edu  |        Owner:         
        Type:  bug                     |       Status:  new    
    Priority:  normal                  |    Milestone:         
   Component:  Compiler                |      Version:  6.4    
    Severity:  normal                  |     Keywords:         
          Os:  MacOS X                 |   Difficulty:  Unknown
Architecture:  Unknown                 |  
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data F c a = F (c a)

 data Val c a = Val (F c) a  --- should produce a kind error but doesn't

 t = Val (F [True]) False --- here we get the impossible

 ---------------------------------------
 dhcp38-137:~/writing/exrep sweirich$ ghci test.hs
    ___         ___ _
   / _ \ /\  /\/ __(_)
  / /_\// /_/ / /  | |      GHC Interactive, version 6.4, for Haskell 98.
 / /_\\/ __  / /___| |      http://www.haskell.org/ghc/
 \____/\/ /_/\____/|_|      Type :? for help.

 Loading package base-1.0 ... linking ... done.
 Compiling Main             ( test.hs, interpreted )
 ghc-6.4: panic! (the `impossible' happened, GHC version 6.4):
         Unify.unifyTauTyLists: mismatched type lists!

 Please report it as a compiler bug to glasgow-haskell-bugs at haskell.org,
 or http://sourceforge.net/projects/ghc/.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/819>
GHC <http://www.haskell.org/ghc/>
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