anchor.diff:      return getName(library, originalName,
                      () => generateUniqueName(originalName));
     }
  -
  -  // Rename main() right now so that nobody takes its place.
  -  renameElement(compiler.mainApp.find(Compiler.MAIN));
   
     placeholderCollector.nullNodes.forEach((Node node) {
       renames[node] = '';
  
positive.code:         });
    });
  }
  
negative.code:     // local identifiers.
      String originalName = element.name.slowToString();
      LibraryElement library = element.getLibrary();
      if (library === compiler.coreLibrary
          || element == compiler.mainApp.find(Compiler.MAIN)) return originalName;
      if (isDartCoreLib(compiler, library)) {
        final prefix =
            imports.putIfAbsent(library, () => generateUniqueName('p'));
  