[Nix-dev] haskell: overriding mtl/any builtin

[Peter Simons]

Hi Mateusz,

 > Doesn't this assume we can override transformers to 0.4 as well,
 > which we don't seem to be able to do?

builds with an overridden 'transformers' version will work fine as long
as the package doesn't link anything that requires the older version
(such as the 'ghc' package). That's a severe restriction on the set of
packages that can be compiled in such a setup, but some builds will
doubtlessly succeed.

I hope this helps,
Peter