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

[Ivan Lazar Miljenovic]

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