Coming from #337 , we set resolver: ghc-7.10 and specify dependencies in extra-deps.

We had PR'd Kmett's nats to relax upper-bound from base < 4.8 so it would work with GHC 7.10. It's probably worth seeing: ekmett/nats#10 (comment)

Note: It is very likely that you'll run into more issues of this sort if stack isn't capable of disambiguating dependencies by compiler version.

Anyway.

The issue here is that stack doesn't appear to support revisions (x-revision in .cabal file). How would one specify that want package X.Y.Z revision N?