ghcs.nix

This is a repository of nix derivations for various GHC versions. The intent is to have complete coverage of all recent GHC releases.

There is a Cachix cache containing pre-built binaries here.

Usage

First install nix and (if you want to use the binary cache) the cachix client:

$ curl -L https://nixos.org/nix/install | sh
$ nix-env -iA cachix -f https://cachix.org/api/v1/install
$ cachix use ghc

Next clone this repository and build the desired compiler:

$ git clone https://gitlab.haskell.org/bgamari/ghcs-nix
$ nix build -f . ghc-9_2_1-rc1

There is also a convenient get_ghc script which can be used to populate a symlink to a requested set of compilers:

$ ./get_ghc 9.0.1
$ ./ghcs/9.0.1/bin/ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.0.1

You can also get a compiler without cloning the repository:

$ nix run -f https://gitlab.haskell.org/bgamari/ghcs-nix/-/archive/master/ghcs-nix-master.tar.gz ghc-9_0_1
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.0.1

Your compiler will be available via the created result/ symlink:

$ result/bin/ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.0.0.20201227

You can instruct cabal-install to use this compiler via the -w flag:

$ cd my-project/
$ cabal v2-build -w /path/to/result/bin/ghc

For use with pre-release GHCs you might want to use the head.hackage patch-set.

Additionally, there are a variety of options for configuring the GHC build. See the argument block in ghc.nix for details. For instance, to build a compiler against the integer-simple (known in more recent GHC releases as the "native" bignum backend), simply run:

$ nix build -f . '((import ./. {}).ghc_8_10_2.override { enableIntegerSimple = true; })'

Other resources

• @mpickering's ghc-artefact-nix is another approach for using existing GHC binary distributions under NixOS.

• @mpickering's old-ghc-nix is a collection of GHC releases packaged using ghc-artefact-nix.

• head.hackage is a set of patches for adapting Hackage packages for use with GHC pre-releases.