anchor.diff:  
     prevent-ifd-gc = let
       srcs = lib.attrValues sources ++ haskellPackagesWithOverrides.haskell-prevent-ifd-gc;
  -    in writeTextDir "prevent-ifd-gc" (toString srcs + "\n");
  +    in writeTextDir "prevent-ifd-gc" (lib.concatMapStringsSep "\n" toString srcs + "\n");
   
   in build // { inherit env hie; }
  
positive.code:       });
  
        # To make certain IFD deps survive GC.
        haskell-prevent-ifd-gc = [] ++
          buildPackages.haskellPackages.cabal2nix.all;
      };
    };
  
  
negative.code: 
    watchexec = (import sources.nixpkgsWatchexec {}).watchexec;
  
    hie = (import sources.hie-nix { pkgs = import sources.hie-nix-nixpkgs {}; }).hie82;
  
  in with (import sources.nixpkgs {}); with (ulib pkgs); let
  
  