anchor.diff:    /// ;
     /// ```
     Token parseLibraryName(Token token) {
  -    // TODO(brianwilkerson) Accept the last consumed token.
  -    assert(optional('library', token));
  -    Token libraryKeyword = token;
  +    Token libraryKeyword = token.next;
  +    assert(optional('library', libraryKeyword));
       listener.beginLibraryName(libraryKeyword);
  -    token = parseQualified(token, IdentifierContext.libraryName,
  +    token = parseQualified(libraryKeyword, IdentifierContext.libraryName,
           IdentifierContext.libraryNameContinuation);
       token = ensureSemicolon(token.next);
       listener.endLibraryName(libraryKeyword, token);
  
positive.code:   /// Parse any top-level declaration that begins with a keyword.
    Token parseTopLevelKeywordDeclaration(
        Token abstractToken, Token token, DirectiveContext directiveState) {
      // TODO(brianwilkerson) Accept the last consumed token.
      assert(token.isTopLevelKeyword);
      final String value = token.stringValue;
      if (identical(value, 'class')) {
  
negative.code:   /// ;
    /// ```
    Token parsePart(Token token) {
      Token partKeyword = token.next;
      assert(optional('part', partKeyword));
      listener.beginPart(partKeyword);
      token = parseLiteralStringOrRecoverExpression(partKeyword);
      token = ensureSemicolon(token);
      listener.endPart(partKeyword, token);
      return token;
  