anchor.diff:      for (var i = 0; i < imap.size; i++) {
         vs.add(imap.getValue(i));
       }
  +
  +    vs = vs.toSet().toList();
   
       for (var value in vs) {
         if (value != null &&
  
positive.code:     for (var i = 0; i < cmap.size; i++) {
        vs.add(cmap.getValue(i));
      }
      for (var i = 0; i < imap.size; i++) {
        vs.add(imap.getValue(i));
      }
  
      for (var value in vs) {
        if (value != null &&
  
negative.code:         !value.isOperator &&
          value.enclosingElement != null &&
          value.enclosingElement.name != 'Object') {
          var lib = value.library == library.element ? library : new Library(value.library, package);
          _inheritedMethods.add(new Method(value, lib));
        }
      }
  