[Nix-dev] ghc-7.6.3 vs haskellPlatform collision

[Marc Weber]

I haven't looked at details.
The main assumption: one ghc works for all could be wrong.

hack-nix and nixpkgs-haskell-overlay assume that and only build
particular environments for target packages. Thus instead of
having one env to build executable EA EB EC you get three which may
have common dependencies. Therefore you do no longer install ghc,
instead you install a scitp-{A,B,C} which augment PATH as needed to
build EA, EB, EC. Its an open question which is the best way to handle
this all. Peter and Andres Loeh have shown that the standard way works
great for almost all use cases.

Marc Weber