[GHC] #14315: GHC panic caused by destructuring with qualified name

4 Oct 2017

      #14315: GHC panic caused by destructuring with qualified name
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           Reporter:  bloxx             |             Owner:  (none)
               Type:  bug               |            Status:  new
           Priority:  normal            |         Milestone:
          Component:  Compiler          |           Version:  8.2.1
           Keywords:                    |  Operating System:  Linux
       Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
          Test Case:                    |        Blocked By:
           Blocking:                    |   Related Tickets:
Differential Rev(s):                    |         Wiki Page:
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 I have a cabal project with the following files:
 {{{#!hs
 -- src/Alt.hs
 module Alt where

 data Pizza = Pizza { filling :: String }

 -- ===========
 -- src/Main.hs
 module Main where

 import qualified Alt as A

 data Pizza = Pizza { filling :: String }

 unpizza :: A.Pizza -> String
 -- to fix it, replace "filling" with "A.filling"
 unpizza A.Pizza { filling = filling } = filling

 main :: IO ()
 main = putStrLn "Hello Haskell!"
 }}}

 Of course, this is not valid code. "filling" belongs to "Pizza" and
 "A.filling" belongs to "A.Pizza". But it causes a panic in GHC 8.2.1
 instead of an error, so I suppose it is a bug. Can you reproduce this
 behavior?

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14315
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