anchor.diff:          name = "postgrest-hsie-graph-symbols";
           docs = "Create a PNG graph of symbols imported within the codebase.";
         }
  -      ''${hsieMinimalImports} graph-symbols | ${graphviz}/bin/dot -Tpng -o "$1"'';
  +      ''
  +        outfile="''${1:?outfile not set}"
  +        ${hsieMinimalImports} graph-symbols | ${graphviz}/bin/dot -Tpng -o "$outfile"
  +      '';
   in
   buildEnv {
     name = "postgrest-devtools";
  
positive.code:         inRootDir = true;
        }
        ''
          dumpdir="$1"
          tmpdir="$(mktemp -d)"
          mkdir -p "$dumpdir"
          ${cabal-install}/bin/cabal v2-build ${devCabalOptions} \
  
negative.code:         name = "postgrest-hsie-graph-modules";
          docs = "Create a PNG graph of modules imported within the codebase.";
        }
        ''
          outfile="''${1:?outfile not set}"
          ${hsie} graph-modules main src | ${graphviz}/bin/dot -Tpng -o "$outfile"
        '';
  
    hsieGraphSymbols =
      checkedShellScript
  