Don Stewart wrote:
ashley:
Thomas Davie wrote:
I'd be interested to see your other examples -- because that error is not happening in Haskell! You can't argue that Haskell doesn't give you no segfaults, because you can embed a C segfault within Haskell.
This segfaults on my x86_64 Linux box:
module Main where import Data.Typeable import Data.IORef data T = T instance Typeable T where typeOf _ = typeOf (undefined :: IORef ()) main :: IO () main = writeIORef (maybe undefined id (cast T)) ()
You'll note nothing marked "Foreign" or "unsafe", and only the base library used. Does the segfault "happen in Haskell" or not?
You just wrote unsafeCoere# a different way:
typeOf T = typeOf (undefined :: IORef ())
Manual Typeable deriving should probably be disabled :-)
But then we need stand-alone deriving clause, otherwise you are lost if someone didn't derive Typeable in her library. We need stand-alone deriving anyway. Cheers Ben