[GHC] #8570: In a pattern binding:ghc: panic! (the 'impossible' happened): Bogus selector Id

[GHC]

#8570: In a pattern binding:ghc: panic! (the 'impossible' happened): Bogus
selector Id
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        Reporter:  rzetterberg         |            Owner:
            Type:  bug                 |           Status:  new
        Priority:  normal              |        Milestone:
       Component:  Compiler            |          Version:  7.6.3
      Resolution:                      |         Keywords:
Operating System:  Linux               |     Architecture:  x86_64 (amd64)
 Type of failure:  Compile-time crash  |       Difficulty:  Unknown
       Test Case:                      |       Blocked By:
        Blocking:                      |  Related Tickets:
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Comment (by simonpj):

 I can't reproduce this.  Here are the modules I used.  I used these
 modules:
 {{{
 module T8570a where
   data Image = Image
     { id :: Integer
     , categoryId :: Integer
     , name :: String
     , filepath :: String
     } deriving (Show)

 module T8570b where
   data Field
     = Password   String
     | Image      Int

 module T8570 where
   import T8570a (Image(filepath))
   import T8570b (Field(..))

   foo logo = fp where Image{filepath = fp} = logo
 }}}
 I compiled thus:
 {{{
 bash$ ghc -c T8570a.hs
 bash$ ghc -c T8570b.hs
 bash$ ghc -c T8570.hs

 T8570.hs:6:27:
     Constructor `Image' does not have field `filepath'
     In the pattern: Image {filepath = fp}
     In a pattern binding: Image {filepath = fp} = logo
     In an equation for `foo':
         foo logo
           = fp
           where
               Image {filepath = fp} = logo
 }}}
 I tried with ghc-7.6.3 and HEAD.  They all work fine.

 Can you offer a precise, reproducible test case?  Thanks

 Simon

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8570#comment:1>
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