anchor.diff:        compiler.enqueuer.resolution.resolvedElements;
   
     ConflictingRenamer(this.compiler) :
  -      renamed = new Map<Element, String>(),
  +      renamed = new Map<LibraryElement, Map<String, String>>(),
         usedTopLevelIdentifiers = new Set<String>(),
         imports = new Map<LibraryElement, String>();
   
  
positive.code:     }
  
      String originalName = element.name.slowToString();
      // TODO(antonm): we should rename lib private names as well.
      if (!element.isTopLevel()) return originalName;
      final library = element.getLibrary();
  
negative.code:  */
  class ConflictingRenamer extends Renamer {
    final Compiler compiler;
    final Map<LibraryElement, Map<String, String>> renamed;
    final Set<String> usedTopLevelIdentifiers;
    final Map<LibraryElement, String> imports;
    TreeElements contextElements;
  