[Haskell-cafe] Cabal: top level dependency base -any

[Jacek Generowicz]

On 2011 May 24, at 09:28, Andres Loeh wrote:

> Hi.
>
>> Could anyone shed light on the meaning of this error message?
>>
>> cabal: cannot configure xmonad-0.9.1 It requires base ==3.*
>> For the dependency on base ==3.* there are these packages:  
>> base-3.0.3.1 and
>> base-3.0.3.2. However none of them are available.
>> base-3.0.3.1 was excluded because of the top level dependency base - 
>> any
>> base-3.0.3.2 was excluded because of the top level dependency base - 
>> any
>
> It's not a great error message. Yes, xmonad-0.9.1 requires base ==3.*.
> So far, so good. Now, base is a special package. It comes with ghc,
> and cannot be upgraded. That's why Cabal will rule out all base
> versions but the one you already have installed. If you have a recent
> ghc, that'll be base-4.
>
> So Cabal is correct to fail in this case: you cannot install this
> version of xmonad with this version of ghc.

That makes sense. Thanks your the explanation.

So would it be correct to infer that the -any restriction will only  
(and always) come into play with special packages such as base?

Are there any other special packages besides base?