anchor.diff:            _module.check = mkOption {
               type = types.bool;
               internal = true;
  -            default = check;
  +            default = true;
               description = "Whether to check whether all option definitions have matching declarations.";
             };
   
  
positive.code:                   check ? true
                  }:
      let
        # 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.
        internalModule = rec {
          _file = ./modules.nix;
  
  
negative.code:         prefix ? [],
          }:
            evalModules (evalModulesArgs // {
              modules = regularModules ++ modules;
              specialArgs = evalModulesArgs.specialArgs or {} // specialArgs;
              prefix = extendArgs.prefix or evalModulesArgs.prefix;
            });
  