[GHC] #7422: GHC panics while trying to derive Generic for GADT with kind-lifted phantom parameter

[GHC]

#7422: GHC panics while trying to derive Generic for GADT with kind-lifted phantom
parameter
-------------------------------+--------------------------------------------
Reporter:  rpglover64          |          Owner:          
    Type:  bug                 |         Status:  new     
Priority:  normal              |      Component:  Compiler
 Version:  7.4.1               |       Keywords:          
      Os:  MacOS X             |   Architecture:  x86     
 Failure:  Compile-time crash  |      Blockedby:          
Blocking:                      |        Related:          
-------------------------------+--------------------------------------------
 This may be a duplicate of #5884

 Compiling the attached file gives the following crash:

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.4.1 for i386-apple-darwin):
         tcTyVarDetails ( tag{tv ae8} [tv] :: main:Main.ExprTag{tc rdD} )
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7422>
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