anchor.diff:      return token;
     }
   
  -  /// Returns true if the stringValue of the [token] is either [value1],
  +  /// Returns `true` if the stringValue of the [token] is either [value1],
     /// [value2], or [value3].
     bool isOneOf3(Token token, String value1, String value2, String value3) {
       String stringValue = token.stringValue;
  
positive.code:   }
  
    Token parseYieldStatement(Token token) {
      Token begin = token;
      listener.beginYieldStatement(begin);
      assert(identical('yield', token.stringValue));
      token = token.next;
      Token starToken;
      if (optional('*', token)) {
  
negative.code:     }
    }
  
    /// Recover given out-of-order clauses in an import directive where [token] is
    /// the import keyword and [recoveryStart] is the token on which main parsing
    /// stopped.
    Token parseImportRecovery(Token token, Token recoveryStart) {
      final primaryListener = listener;
      final recoveryListener = new ImportRecoveryListener(primaryListener);
  