[GHC] #7142: ghc: panic! (the 'impossible' happened) when using lowercase eq/show in deriving

[GHC]

#7142: ghc: panic! (the 'impossible' happened) when using lowercase eq/show in
deriving
--------------------------------+-------------------------------------------
 Reporter:  mbrodersen          |          Owner:          
     Type:  bug                 |         Status:  new     
 Priority:  normal              |      Component:  Compiler
  Version:  7.4.1               |       Keywords:          
       Os:  Linux               |   Architecture:  x86     
  Failure:  Compile-time crash  |       Testcase:          
Blockedby:                      |       Blocking:          
  Related:                      |  
--------------------------------+-------------------------------------------
 Compiling the following:
 -----------------------------------------------------------
 module Main where

 data Tree a = Edge a | Node (Tree a) (Tree a)
                           deriving (eq,show)

 main10 = print $ Node (Edge 10) (Edge 20)

 main = main10
 -----------------------------------------------------------
 Results in:
 -----------------------------------------------------------
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.4.1 for i386-unknown-linux):
         nameModule eq{tv a9O}

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 -----------------------------------------------------------

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7142>
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