anchor.diff:     *     namedFormalParameters ::=
      *         '{' defaultNamedParameter (',' defaultNamedParameter)* '}'
      */
  -  FormalParameterList parseFormalParameterList({bool inFunctionType = false}) {
  +  FormalParameterList parseFormalParameterList({bool inFunctionType: false}) {
       if (_matches(TokenType.OPEN_PAREN)) {
         return _parseFormalParameterListUnchecked(inFunctionType: inFunctionType);
       }
  
positive.code:    *         normalFormalParameter (':' expression)?
     */
    FormalParameter parseFormalParameter(ParameterKind kind,
        {bool inFunctionType = false}) {
      NormalFormalParameter parameter =
          parseNormalFormalParameter(inFunctionType: inFunctionType);
      TokenType type = _currentToken.type;
  
negative.code:    * This method assumes that the current token matches `TokenType.OPEN_PAREN`.
     */
    FormalParameterList _parseFormalParameterListUnchecked(
        {bool inFunctionType: false}) {
      return _parseFormalParameterListAfterParen(getAndAdvance(),
          inFunctionType: inFunctionType);
    }
  