anchor.diff:    haskellPackages = nixpkgs.haskell.packages."${compiler}".override (old: {
       overrides = nixpkgs.lib.composeExtensions (old.overrides or (_: _: {})) (self: super: {
         ihaskell          = nixpkgs.haskell.lib.overrideCabal (
  -                          self.callCabal2nix "ihaskell" ihaskell-src {}) (drv: {
  +                          self.callCabal2nix "ihaskell" ihaskell-src {}) (_drv: {
           preCheck = ''
             export HOME=$TMPDIR/home
             export PATH=$PWD/dist/build/ihaskell:$PATH
             export GHC_PACKAGE_PATH=$PWD/dist/package.conf.inplace/:$GHC_PACKAGE_PATH
           '';
  -        configureFlags = (drv.configureFlags or []) ++ [
  -          # otherwise the tests are agonisingly slow and the kernel times out
  -          "--enable-executable-dynamic"
  -        ];
           doHaddock = false;
         });
         ghc-parser        = self.callCabal2nix "ghc-parser" ghc-parser-src {};
  
positive.code:       static-canvas     = nixpkgs.haskell.lib.doJailbreak super.static-canvas;
      } // displays self);
    });
    ihaskellEnv = haskellPackages.ghcWithPackages packages;
    jupyterlab = nixpkgs.python3.withPackages (ps: [ ps.jupyterlab ] ++ pythonPackages ps);
  
    ihaskellWrapperSh = nixpkgs.writeShellScriptBin "ihaskell-wrapper" ''
      export PATH="${nixpkgs.lib.makeBinPath ([ ihaskellEnv jupyterlab ] ++ systemPackages nixpkgs)}''${PATH:+:}$PATH"
      exec ${haskellPackages.ihaskell}/bin/ihaskell "$@"
    '';
  
    ihaskellGhcLib = nixpkgs.writeShellScriptBin "ihaskell" ''
      ${haskellPackages.ihaskell}/bin/ihaskell -l $(${ihaskellEnv}/bin/ghc --print-libdir) "$@"
    '';
  
    kernelFile = {
  
negative.code: 
    passthru = {
      inherit haskellPackages;
      inherit ihaskellExe;
      inherit ihaskellEnv;
      inherit jupyterlab;
      inherit ihaskellWrapperSh;
  