Re: Bug in GHC 6.4.1 and 6.4.2

2006-07-21 Thread Simon Marlow 

Fritz Henglein wrote:

According to a message from GHCi, version 6.4.1 (see below; bug also
reproduceable with 6.4.2, though not shown here since it consistently
resulted in a core dump without prior message) under Windows XP (fully
updated per 2006-07-15), I am herewith reporting what appears to be a
bug in GHC.  Please see transcript below; the source file in question
is included as an attachment.  (Lacking both efficient Haskell
programming skills and an understanding of the internals of GHC I have
refrained from attempting to isolate the bug by reducing the code.)
Should there be a simple work-around or something unsafe in my code
(though I wouldn't know what: no unsafe operations are used; no
polymorphism is present), I would greatly appreciate hearing about it.


Thanks, good bug.  The problem was:

 index (minBound::Int16,maxBound) maxBound
-1

ie. index for Int16 should have converted to Int *before* doing the subtraction.

This is related to another problem (that I think we have a ticket for), namely 
that the type of index precludes having really large arrays:


  index :: Ix i = (i,i) - i - Int

if the index must fit in an Int, then GHC can't cope with arrays with more than 
2^31 elements (on a 32-bit machine), and in general Haskell doesn't allow arrays 
with more than 2^29 elements.


Cheers,
Simon
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Bug in GHC 6.4.1 and 6.4.2

2006-07-20 Thread Fritz Henglein 

According to a message from GHCi, version 6.4.1 (see below; bug also
reproduceable with 6.4.2, though not shown here since it consistently
resulted in a core dump without prior message) under Windows XP (fully
updated per 2006-07-15), I am herewith reporting what appears to be a
bug in GHC.  Please see transcript below; the source file in question
is included as an attachment.  (Lacking both efficient Haskell
programming skills and an understanding of the internals of GHC I have
refrained from attempting to isolate the bug by reducing the code.)
Should there be a simple work-around or something unsafe in my code
(though I wouldn't know what: no unsafe operations are used; no
polymorphism is present), I would greatly appreciate hearing about it.

Sincerely,
Fritz



:load c:/henglein/Software/haskell/Basic.hs
  ___ ___ _
 / _ \ /\  /\/ __(_)
/ /_\// /_/ / /  | |  GHC Interactive, version 6.4.1, for Haskell 98.
/ /_\\/ __  / /___| |  http://www.haskell.org/ghc/
\/\/ /_/\/|_|  Type :? for help.

Loading package base-1.0 ... linking ... done.
Prelude Compiling BasicDiscrimination (
c:/henglein/Software/haskell/Basic.hs, interpreted )
Ok, modules loaded: BasicDiscrimination.
*BasicDiscrimination d - mkDiscriminator
Loading package haskell98-1.0 ... linking ... done.
*BasicDiscrimination res - d [(5, kdjfkd), (8, kjdkfjd)]
interactive: internal error: EVACUATED object entered!
   Please report this as a bug to glasgow-haskell-bugs@haskell.org,
   or http://www.sourceforge.net/projects/ghc/


--
Fritz Henglein, Ph.D.
Professor mso
Dept. of Computer Science, University of Copenhagen (DIKU)
Universitetsparken 1
DK-2100 Copenhagen
Denmark
Email: [EMAIL PROTECTED]
Tel.: +45-35321463 (office), +45-41414158 (cell)
Skype: henglein


Basic.hs
Description: Binary data
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