anchor.diff:    }
   
     Token parseNativeClause(Token nativeToken) {
  +    assert(optional('native', nativeToken));
       Token token = nativeToken.next;
       bool hasName = false;
       if (token.kind == STRING_TOKEN) {
  
positive.code:   /// ```
    Token parseOptionalFormalParameters(
        Token token, bool isNamed, MemberKind kind) {
      assert((isNamed && optional('{', token)) || optional('[', token));
      Token begin = token;
      listener.beginOptionalFormalParameters(begin);
      int parameterCount = 0;
  
negative.code:   /// ;
    /// ```
    Token parseDottedName(Token token) {
      Token firstIdentifier =
          ensureIdentifier(token, IdentifierContext.dottedName);
      listener.beginDottedName(firstIdentifier);
      token = firstIdentifier.next;
      int count = 1;
      while (optional('.', token)) {
  