anchor.diff:          # include it in the result, it *is* available to nix-env for
           # queries.  We also a meta.position attribute here to
           # identify the source location of the package.
  -        meta = attrs.meta or {} // (if pos != null then {
  -          position = pos.file + ":" + (toString pos.line);
  +        meta = meta // (if pos != null then {
  +          position = pos.file + ":" + toString pos.line;
           } else {});
  -        passthru = attrs.passthru or {};
  +        inherit passthru;
         } //
         # Pass through extra attributes that are not inputs, but
         # should be made available to Nix expressions using the
         # derivation (e.g., in assertions).
  -      (attrs.passthru or {}));
  +      passthru);
   
     # The stdenv that we are producing.
     result =
  
positive.code:           nativeBuildInputs = nativeBuildInputs ++ (if crossConfig == null then buildInputs else []);
            propagatedNativeBuildInputs = propagatedNativeBuildInputs ++
              (if crossConfig == null then propagatedBuildInputs else []);
          }))) (
        {
          # The meta attribute is passed in the resulting attribute set,
          # but it's not part of the actual derivation, i.e., it's not
  
negative.code: 
        lib.addPassthru (derivation (
          (removeAttrs attrs ["meta" "passthru" "crossAttrs"])
          //
          {
            builder = attrs.realBuilder or shell;
            args = attrs.args or ["-e" (attrs.builder or ./default-builder.sh)];
  