[GHC] #12158: ghc: panic! (the 'impossible' happened) translateConPatVec: lookup

[GHC]

#12158: ghc: panic! (the 'impossible' happened)  translateConPatVec: lookup
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        Reporter:  wozgonon          |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Windows           |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by wozgonon):

 -- 1) Place code at the end of this comment into a source file: test.hs
 -- 2) In WinCHCI
 --    Prelude> :load test.hs
 --    *Main> price Stock{name=name,ric=ric,price=price} = price
 -- 3) Observe error message:
 -- ghc: panic! (the 'impossible' happened)
 --   (GHC version 8.0.1 for x86_64-unknown-mingw32):
 --      translateConPatVec: lookup
 --
 -- Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug


 --test.hs
 data Stock = Stock {name :: String, ric :: String, price :: Float}
 deriving (Show)
 arm  = Stock {name="ARM Holdings", ric="ARM.L", price=999}
 iii  = Stock {name="3I Group PLC", ric="III.L", price=549}
 stockprice(Stock{name=name,ric=ric,price=price})=price
 type Holding   = (Stock,Int)
 stock  h= fst h
 shares h= snd h
 value  h=stockprice(stock h)*fromIntegral(shares(h))
 type Portfolio = [Holding]
 portfolio= [(arm, 198), (iii, 0)]
 list= map value portfolio

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12158#comment:3>
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