anchor.diff:      this.handleStack = this.handleStack.splice(0, start);
     }
     
  -  // Make this ID globally scope.  It must be explicitly invalidated.
  +  // Makes this ID globally scope.  It must be explicitly invalidated.
     ProxiedReferenceTable.prototype.globalize = function(id) {
       this.globalIds[id] = true;
     }
   
  -  // Invalidate this ID, potentially freeing its corresponding object.
  +  // Invalidates this ID, potentially freeing its corresponding object.
     ProxiedReferenceTable.prototype.invalidate = function(id) {
       var old = this.get(id);
       delete this.globalIds[id];
  
positive.code:   final _id;
  
    /**
     * Construct a [Proxy] to a new JavaScript object by invoking a (proxy to a)
     * JavaScript [constructor].  The arguments should be either
     * primitive values, DOM elements, or Proxies.
     */
  
negative.code:   });
  }
  
  // Evaluates a JavaScript string and return
  _js(String message) => _deserialize(_jsPortSync.callSync(_serialize(message)));
  
  /**
   * Returns a proxy to the global JavaScript context for this page.
   */
  Proxy get context {
    if (_depth == 0) throw 'Cannot get JavaScript context out of scope.';
  