anchor.diff:                    check ? true
                   }:
       let
  +      legacyModules =
  +        optional (evalModulesArgs?args) {
  +          config = {
  +            _module.args = args;
  +          };
  +        }
  +        ++ optional (evalModulesArgs?check) {
  +          config = {
  +            _module.check = mkDefault check;
  +          };
  +        };
  +      regularModules = modules ++ legacyModules;
  +
         # This internal module declare internal options under the `_module'
         # attribute.  These options are fragile, as they are used by the
         # module system to change the interpretation of modules.
  +      #
  +      # When extended with extendModules or moduleType, a fresh instance of
  +      # this module is used, to avoid conflicts and allow chaining of
  +      # extendModules.
         internalModule = rec {
           _file = ./modules.nix;
   
  
positive.code:           _module.args = {
              inherit extendModules;
              moduleType = type;
            } // args;
          };
        };
  
        merged =
          let collected = collectModules
            (specialArgs.modulesPath or "")
            (modules ++ [ internalModule ])
            ({ inherit lib options config specialArgs; } // specialArgs);
          in mergeModules prefix (reverseList collected);
  
  
negative.code:         prefix ? [],
          }:
            evalModules (evalModulesArgs // {
              modules = regularModules ++ modules;
              specialArgs = evalModulesArgs.specialArgs or {} // specialArgs;
              prefix = extendArgs.prefix or evalModulesArgs.prefix;
            });
  