final ParserImpl p4 = parserImpl(commentString + "import");
checkParseResult(comments, p4.importKeyword(), p4);
final ParserImpl p5 = parserImpl(commentString + "hello");
checkParseResult(_Tuple(comments, "hello"), p5.commentedIdentifier("an identifier"), p5);
final ParserImpl p6 = parserImpl(commentString + "@");
checkParseResult(comments, p6.at(true), p6);
}