[GHC] #10965: GHC Panic on import with 'OPTIONS_GHC -fobject-code -O'

13 Oct 2015


      #10965: GHC Panic on import with 'OPTIONS_GHC -fobject-code -O'
--------------------------------------+---------------------------------
           Reporter:  Orome           |             Owner:
               Type:  bug             |            Status:  new
           Priority:  normal          |         Milestone:
          Component:  Compiler        |           Version:  7.10.2
           Keywords:                  |  Operating System:  MacOS X
       Architecture:  x86_64 (amd64)  |   Type of failure:  None/Unknown
          Test Case:                  |        Blocked By:
           Blocking:                  |   Related Tickets:
Differential Rev(s):                  |         Wiki Page:
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 I get


 {{{
...
:l Test.hs
 [1 of 1] Compiling Main             ( Test.hs, interpreted )
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.10.2 for x86_64-apple-darwin):
         floatExpr tick break<11>()
Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

 with Test.hs:


 {{{
 {-# OPTIONS_GHC -fobject-code -O #-}

 import Control.Exception (assert)
 import Data.Char (ord)

 f :: String -> String
 f s = assert (all (`elem` letters) s) $ (letters!!) <$> (ix <$> s)
     where
         ix ch = (ord ch - ord 'A')
         letters = ['A'..'Z']
 }}}

 OSX 10.11, GHC 7.10.2; uad-core 64-bit haswell; Homebrew GHC

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10965
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