This makes it work like work-on-multi from Reflex Platform. In
particular, rather than making `.env` from `shellFor`, we make `.env`
the primitive, and `shellFor` works by combining together the arguments
of all the packages to `generic-builder` and taking the `.env` of the
resulting mashup-package.
There are 2 benefits of this:
1. The dependency logic is deduplicated. generic builder just concatted
lists, whereas all the envs until now would sieve apart haskell and
system build inputs. Now, they both decide haskell vs system the same
way: according to the argument list and without reflection.
Consistency is good, especially because it mean that if the build
works, the shell is more likely to work.
2. Cross is handled better. For native builds, because the
`ghcWithPackages` calls would shadow, we through both the regular
component (lib, exe, test, bench) haskell deps and Setup.hs haskell
deps in the same `ghcWithPackages` call. But for cross builds we use
`buildPackages.ghcWithPackages` to get the setup deps. This ensures
everything works correctly.
When visiting local documentation via hoogle, currently for most packages the
quickjump index is missing so you only get a sad error when pressing "s" to
search in the current documentation.
The quickjump option is only supported by the haddock utility that's shipped
with ghc 8.6.x or later.
Closes https://github.com/NixOS/nixpkgs/pull/75942.
We made an effort to support ghcide in Nixpkgs, but the complexity of the
problem is a bit too high, IMHO. We need to keep older versions of several
packages around in order to satisfy the build requirements, and some of those
older packages don't even build themselves (like hie-bios). We had ghcide
working at some point, but then it was broken again right away after a couple
of days. I fear that we'll run into that issue again and again with a setup of
that complexity.
Instead, I'd propose that we work with upstream to fix their build, i.e. let's
make sure that the proper ghcide build works with recent versions of its build
inputs.
Closes https://github.com/NixOS/nixpkgs/pull/75449.
Closes https://github.com/NixOS/nixpkgs/pull/76103.
