#1728: generic classes broken
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    Reporter:  [EMAIL PROTECTED]  |        Owner:         
        Type:  bug                   |       Status:  new    
    Priority:  normal                |    Milestone:         
   Component:  Compiler              |      Version:  6.8    
    Severity:  normal                |   Resolution:         
    Keywords:                        |   Difficulty:  Unknown
          Os:  Linux                 |     Testcase:         
Architecture:  x86                   |  
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Comment (by guest):

 Sorry for the broken formatting...

 I tried (see attachment):

 {{{
 module Gen where

 import Data.Generics

 class Equal a where
      equal :: a -> a -> Bool
      equal {| Unit |}    Unit        Unit        = True
      equal {| u :+: v |} (Inl x)     (Inl y)     = equal x y
      equal {| u :+: v |} (Inr x)     (Inr y)     = equal x y
      equal {| u :+: v |} _           _           = False
      equal {| u :*: v |} (x1 :*: x2) (y1 :*: y2) = equal x1 y1 && equal x2
 y2

 instance Equal Bool

 }}}

 and got

 {{{
 [EMAIL PROTECTED]:~/tmp> ghci -fglasgow-exts -XGenerics
 GHCi, version 6.8.0.20070920: http://www.haskell.org/ghc/  :? for help
 Loading package base ... linking ... done.
 Prelude> :l Gen.hs
 [1 of 1] Compiling Gen              ( Gen.hs, interpreted )

 Gen.hs:13:0:
        Can't find interface-file declaration for variable
 GHC.Base.$gfromBool
          Probable cause: bug in .hi-boot file, or inconsistent .hi file
          Use -ddump-if-trace to get an idea of which file caused the error
        In the first argument of `a', namely `(GHC.Base.$gfromBool b)'
        In the first argument of `(\ a -> a)', namely
            `(a (GHC.Base.$gfromBool b))'
        In the expression: (\ a -> a) (a (GHC.Base.$gfromBool b))
 Failed, modules loaded: none.
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1728>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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