anchor.diff:    void set name(Identifier identifier);
   
     /**
  -   * The question mark indicating that the type is nullable, or `null` if there
  -   * is no question mark.
  -   */
  -  Token get question;
  -
  -  /**
      * Set the question mark indicating that the type is nullable to the given
      * [token].
      */
  
positive.code:  */
  abstract class TypeAnnotation extends AstNode {
    /**
     * Return the type being named, or `null` if the AST structure has not been
     * resolved.
     */
  
negative.code:    * [parameters].
     */
    void set parameters(FormalParameterList parameters);
  
    /**
     * Set the question mark indicating that the type is nullable to the given
  