anchor.diff:  class LibraryScope extends EnclosedScope {
     /**
      * Initialize a newly created scope representing the names defined in the
  -   * [definingLibrary]. The error listener is no longer used and should be
  -   * omitted.
  +   * [definingLibrary].
      */
     LibraryScope(LibraryElement definingLibrary)
         : super(new LibraryImportScope(definingLibrary)) {
  
positive.code: 
    /**
     * Initialize a newly created scope representing the names imported into the
     * [_definingLibrary]. The error listener is no longer used and should be
     * omitted.
     */
    LibraryImportScope(this._definingLibrary) {
      _createImportedNamespaces();
  
negative.code: 
    /**
     * Add the given [element] to this scope. If there is already an element with
     * the given name defined in this scope, then the original element will
     * continue to be mapped to the name.
     */
    void define(Element element) {
      String name = _getName(element);
  