[Haskell-cafe] Strange discrepancy between Emacs interpreter and command-line on windows

[Arnaud Bailly]

Yes, I have two versions installed , 0.9.1.4 and 0.9.1.6. Here is the
output of ghc-pkg -l:

d:/Program Files/Haskell Platform/2009.2.0.2\package.conf:
    Cabal-1.6.0.3, GLUT-2.1.1.2, HSlim-0.1, HTTP-4000.0.6,
    HUnit-1.2.0.3, OpenGL-2.2.1.1, QuickCheck-1.2.0.0,
    QuickCheck-2.1.0.3, Win32-2.2.0.0, array-0.2.0.0, base-3.0.3.1,
    base-4.1.0.0, bytestring-0.9.1.4, bytestring-0.9.1.6,
    cgi-3001.1.7.1, containers-0.2.0.1, directory-1.0.0.3,
    (dph-base-0.3), (dph-par-0.3), (dph-prim-interface-0.3),
    (dph-prim-par-0.3), (dph-prim-seq-0.3), (dph-seq-0.3),
    extensible-exceptions-0.1.1.0, fgl-5.4.2.2, filepath-1.1.0.2,
    (ghc-6.10.4), ghc-prim-0.1.0.0, haddock-2.4.2, haskell-src-1.0.1.3,
    haskell98-1.0.1.0, hpc-0.5.0.3, html-1.0.1.2, integer-0.1.0.1,
    mtl-1.1.0.2, network-2.2.1.4, old-locale-1.0.0.1, old-time-1.0.0.2,
    packedstring-0.1.0.1, parallel-1.1.0.1, parsec-2.1.0.1,
    pretty-1.0.1.0, process-1.0.1.1, random-1.0.0.1,
    regex-base-0.72.0.2, regex-compat-0.71.0.1, regex-posix-0.72.0.3,
    rts-1.0, stm-2.1.1.2, syb-0.1.0.1, template-haskell-2.3.0.1,
    time-1.1.2.4, utf8-string-0.3.6, xhtml-3000.2.0.1, zlib-0.5.0.0

However, I tried to force the version I use to be 0.9.1.6 and it does
not work as ghc itself seems to require 0.9.1.4, as pointed out by
Ivan. I did not try to remove one or the other however.

Arnaud

On Thu, Jun 10, 2010 at 12:13 AM, Ivan Lazar Miljenovic
<ivan.miljenovic at gmail.com> wrote:
> Don Stewart <dons at galois.com> writes:
>
>> arnaud.oqube:
>>> Hello,
>>> I have a strange issue which sprang today out of nowhere. When I load
>>> a certain file using bytestring package in Ghci using emacs, I got the
>>> following error:
>>>
>>> Couldn't match expected type `Data.ByteString.Internal.ByteString'
>>>            against inferred type
>>> `bytestring-0.9.1.4:Data.ByteString.Internal.ByteString'
>>>     In the second argument of `hPutStrLn', namely `(fromString msgs)'
>>>     In a stmt of a 'do' expression: hPutStrLn cnx (fromString msgs)
>>>
>>> The same file compiles fine on the command-line. I have a single
>>> installation of haskell platform, using ghc 6.10.4, on windows XP.
>>>
>>
>> Looks like you might have two versions of bytestring installed (ghc-pkg
>> list bytestring) and are attempting to combine them. The diamond
>> dependency problem.
>>
>>     * delete the old version (ghc-pkg unregister)
>
> Isn't the old version likely to be the one that comes with GHC and hence
> shouldn't be touched?
>
> --
> Ivan Lazar Miljenovic
> Ivan.Miljenovic at gmail.com
> IvanMiljenovic.wordpress.com
>