anchor.diff:    /// The token representing the 'async' keyword, or `null` if there is no such
     /// keyword.
     @override
  -  Token? keyword;
  +  final Token? keyword;
   
     /// The star optionally following the 'async' or 'sync' keyword, or `null` if
     /// there is wither no such keyword or no star.
  
positive.code: 
    /// The semicolon terminating the statement.
    @override
    Token semicolon;
  
    /// Initialize a newly created variable declaration statement.
    VariableDeclarationStatementImpl({
  
negative.code: class DoStatementImpl extends StatementImpl implements DoStatement {
    /// The token representing the 'do' keyword.
    @override
    final Token doKeyword;
  
    /// The body of the loop.
    StatementImpl _body;
  
    /// The token representing the 'while' keyword.
    @override
    final Token whileKeyword;
  
    /// The left parenthesis.
    @override
    final Token leftParenthesis;
  
    /// The condition that determines when the loop will terminate.
    ExpressionImpl _condition;
  
    /// The right parenthesis.
    @override
    final Token rightParenthesis;
  
    /// The semicolon terminating the statement.
    @override
    final Token semicolon;
  
    /// Initialize a newly created do loop.
    DoStatementImpl({
  