nix-instantiate -A haskell.compiler.ghcjs
error: Package ‘webdriver-0.9.0.1’ in /home/lukas/src/nix/nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix:292014 is marked as broken, refusing to evaluate.

a) To temporarily allow broken packages, you can use an environment variable
   for a single invocation of the nix tools.

     $ export NIXPKGS_ALLOW_BROKEN=1
     
 Note: For `nix shell`, `nix build`, `nix develop` or any other Nix 2.4+
 (Flake) command, `--impure` must be passed in order to read this
 environment variable.
    
b) For `nixos-rebuild` you can set
  { nixpkgs.config.allowBroken = true; }
in configuration.nix to override this.

c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
  { allowBroken = true; }
to ~/.config/nixpkgs/config.nix.

(use '--show-trace' to show detailed location information)