Hi Robert,
> Could we do something in guix like what nixpkgs does, where the dependencies > are encoded, but then “nulled” depending on the compiler version? > > https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/haskell-modules/configuration-ghc-8.4.x.nix#L10 Yes, we could do this in the haskell-build-system (automatically removing inputs before the build is set up). My first reaction was “this is inelegant”, but it does have some advantages: we could rebuild packages with other versions of GHC more easily and it would just work without having to adjust the inputs manually. I think this would be done in guix/build-system/haskell.scm, the “haskell-build” procedure. There we pass all inputs unchanged through to build-expression->derivation. I guess we could filter inputs right there. -- Ricardo
