RE: GHC Crash

It's a delicate area, but yes I think it should work.  It does now, in
the HEAD.

Simon

| -----Original Message-----
| From: Simon Marlow
| Sent: 23 November 2005 12:39
| To: Simon Peyton-Jones
| Cc: Matt
| Subject: RE: GHC Crash
| 
| Simon - this one reports
| 
| ghc-6.5.20051122: panic! (the `impossible' happened, GHC version
6.5.20051122):
|         dsLExpr: tuple pattern:
| [ etc. ]
| 
| it looks like the typechecker should be catching the use of unboxed
tuple in a case scrutinee.  Is GHC
| supposed to do that these days?
| 
| (see ~simonmar/scratch/test373.hs)
| 
| Cheers,
|       Simon
| 
| On 20 November 2005 04:39, Matt wrote:
| 
| > Hello,
| >
| > I found a bug in GHC which causes it to crash. I believe it is
| > related to my experimentation with the unboxed tuple. It was not
| > clear to me from the manual as to whether or not this was legal. My
| > version of GHC reports via -v that it is "Glasgow Haskell Compiler,
| > Version 6.4.1, for Haskell 98, compiled by GHC version 6.4". I am
| > running on Windows XP.
| >
| > A simplified repro of the bug follows:
| >
| > {-# OPTIONS_GHC -fglasgow-exts #-}
| >
| > import qualified Array;
| > import qualified Ix;
| >
| > type Array a b = Array.Array a b
| > type Matrix a b = Array (a, a) b
| >
| > -- Imports from Array.Array for convenience
| > (!) :: Ix.Ix a => Array a b -> a -> b
| > (!) = (Array.!)
| >
| > fweval :: (Ix.Ix a, Integral b) => Matrix a (Maybe b) -> a -> a -> a
| > -> [((a, a), Maybe b)] -> [((a, a), Maybe b)]
| > fweval m i j k upd = case (# m!(i, k), m!(k, j), m!(i, j) #) of
| >                       (# Nothing, _, _ #)             -> upd
| >                       (# _, Nothing, _ #)             -> upd
| >                       (# Just ik, Just kj, Nothing #) -> ((i, j),
Just
| > (ik+kj)):upd
| >                       (# Just ik, Just kj, Just ij #) -> if (ik+kj)
<
| > ij then ((i, j), Just (ik+kj)):upd else upd
| >
| > main :: IO ()
| > main = return ()
| >
| > -Matt
| >
| > _______________________________________________
| > Glasgow-haskell-bugs mailing list
| > Glasgow-haskell-bugs@xxxxxxxxxxx
| > http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs