anchor.diff:  , nixpkgsPath ? ../../..
   , config ? { allowBroken = true; }
   , skipEvalErrors ? true
  +, skipBinaryGHCs ? true
   }:
   
   let
  
positive.code:         builtins.match "ghc-([0-9]+).([0-9]+).x" configName
        );
        # return all package sets under haskell.packages matching the version components
        setsForVersion = builtins.map (name: pkgs.haskell.packages.${name}) (
          builtins.filter (lib.hasPrefix "ghc${configVersion}") (
            builtins.attrNames pkgs.haskell.packages
          )
        );
  
negative.code:      nix-build maintainers/scripts/haskell/test-configurations.nix \
         --arg config '{ allowBroken = false; }' --keep-going
  
     By default the haskell.packages.ghc*Binary sets used for bootstrapping GHC
     are _not_ tested. You can change this using:
  
       nix-build maintainers/scripts/haskell/test-configurations.nix \
         --arg skipBinaryGHCs false --keep-going
  
  */
  { files ? [
      "configuration-common.nix"
  