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, 1.2.2.1)
Looks like a GHC bug. The following code mimics what HUnit does: -- import Control.Exception as E import Data.Typeable 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 print a -- 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 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: http://hackage.haskell.org/trac/ghc/ticket/3959 I don't have a newer GHC version installed, though, so I can't test if it works in a newer GHC. Jürgen