[Haskell-cafe] ghc -O2 and HUnit weirdness
jurgen.doser at gmail.com
Fri Jan 7 00:18:09 CET 2011
El jue, 06-01-2011 a las 16:41 -0400, Joey Hess escribió:
> So, the problem seems to be that ghc -O2 somehow optimises the static
> assertBool _ True away, in what seems to be a bad way. Remove the -O2 and
> the test fails as expected. Presumably, although I have not verified,
> less static boolean values would not trigger the optimisation.
> Is this a ghc or HUnit bug?
> (Versions: 6.12.1, 18.104.22.168)
Looks like a GHC bug. The following code mimics what HUnit does:
import Control.Exception as E
data Fail = Fail deriving (Show)
instance Typeable Fail where typeOf _ = mkTyConApp (mkTyCon "Fail") 
instance Exception Fail
t = (E.throw Fail >> return Nothing) `E.catch` (\Fail -> return $ Just Fail)
main = do a <- t
it runs fine with -O0, but produces an internal error when compiled with -O1 or -O2:
$ ghc --make -O2 t.hs
[1 of 1] Compiling Main ( t.hs, t.o )
Linking t ...
t: internal error: PAP object entered!
(GHC version 6.12.1 for i386_unknown_linux)
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
It looks like the following bug:
I don't have a newer GHC version installed, though, so I can't test if it works in a newer GHC.
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