anchor.diff:    bool _isValidMixin = false;
   
     /**
  +   * A collection holding the elements defined in a class that need to have
  +   * their function type fixed to take into account type parameters of the
  +   * enclosing class, or `null` if we are not currently processing nodes within
  +   * a class.
  +   */
  +  List<ExecutableElementImpl> _functionTypesToFix = null;
  +
  +  /**
      * A table mapping field names to field elements for the fields defined in the current class, or
      * `null` if we are not in the scope of a class.
      */
  
positive.code:         element.setVisibleRange(functionEnd, blockEnd - functionEnd - 1);
        }
      }
      element.type = new FunctionTypeImpl(element);
      element.hasImplicitReturnType = true;
      _currentHolder.addFunction(element);
      node.element = element;
  
negative.code:    * @return the [ConstructorElement]s array with the single default constructor element
     */
    List<ConstructorElement> _createDefaultConstructors(
        ClassElementImpl definingClass) {
      ConstructorElementImpl constructor =
          new ConstructorElementImpl.forNode(null);
      constructor.synthetic = true;
      constructor.returnType = definingClass.type;
      constructor.enclosingElement = definingClass;
      constructor.type = new FunctionTypeImpl(constructor);
      return <ConstructorElement>[constructor];
    }
  