[GHC] #786: bugs around tagToEnum#

[GHC]

#786: bugs around tagToEnum#
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  Reporter:  Bulat.Ziganshin at gmail.com  |          Owner:         
      Type:  bug                        |         Status:  new    
  Priority:  normal                     |      Milestone:         
 Component:  Compiler                   |        Version:  6.4.2  
  Severity:  normal                     |     Resolution:         
  Keywords:                             |             Os:  Unknown
Difficulty:  Unknown                    |   Architecture:  Unknown
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Old description:

> i've enclosed 3 modules which reports various problems. all they use
> tagToEnum# and these bugs may be is because of the following, stated in
> CgExpr.lhs:
>
>           -- If you're reading this code in the attempt to figure
>           -- out why the compiler panic'ed here, it is probably because
>           -- you used tagToEnum# in a non-monomorphic setting, e.g.,
>           --         intToTg :: Enum a => Int -> a ; intToTg (I# x#) =
> tagToEnum# x#
>           -- That won't work.
>         tycon = tyConAppTyCon res_ty

New description:

 i've enclosed 3 modules which reports various problems. all they use
 tagToEnum# and these bugs may be is because of the following, stated in
 CgExpr.lhs:
 {{{
           -- If you're reading this code in the attempt to figure
           -- out why the compiler panic'ed here, it is probably because
           -- you used tagToEnum# in a non-monomorphic setting, e.g.,
           --         intToTg :: Enum a => Int -> a ; intToTg (I# x#) =
 tagToEnum# x#
           -- That won't work.
         tycon = tyConAppTyCon res_ty
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/786>
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