planning for ghc-6.10.1 and hackage

[Simon Marlow]

Duncan Coutts wrote:

> I propose two solutions:
> 
>       * Fix the dependency resolver
>       * Add support in Cabal and Hackage for suggested version
>         constraints

Simon PJ just came up with a suggestion for the second part.  The idea is this:

If we see a dependency like "base >= 3" with no upper limit, we should 
satisfy it with base-3 in preference to base-4, on the grounds that the 
package is much more likely to build with base-3.  This seems to be a 
solution that works without any magic shims or "preference files" or 
anything else.

Perhaps we could even go as far as saying "base >= 3.0" is equivalent to 
"base == 3.0.*".  i.e. if you don't supply an upper bound, then we'll give 
you a conservative one.  I wonder how much stuff would break if we did that.

Cheers,
	Simon