private static async Task <Document> RefactorAsync( Document document, ArgumentSyntax argument, ArgumentListSyntax argumentList, CancellationToken cancellationToken) { SyntaxNode oldRoot = await document.GetSyntaxRootAsync(cancellationToken); SeparatedSyntaxList <ArgumentSyntax> arguments = argumentList.Arguments; int index = arguments.IndexOf(argument); ArgumentSyntax nextArgument = arguments[index + 1] .WithTriviaFrom(argument); arguments = arguments .Replace(argument, nextArgument); arguments = arguments .Replace(arguments[index + 1], argument.WithTriviaFrom(nextArgument)); ArgumentListSyntax newNode = argumentList.WithArguments(arguments); SyntaxNode newRoot = oldRoot.ReplaceNode(argumentList, newNode); return(document.WithSyntaxRoot(newRoot)); }