public static async Task <Document> ChangeArgumentAsync(
Document document,
ArgumentListSyntax argumentListNode,
string newParameterName,
CancellationToken cancellationToken)
{
// Find the Identifier Name for the first argument to Ensure.Arg.
var argumentNodes = argumentListNode.DescendantNodes()
.OfType <ArgumentSyntax>();
if (argumentNodes.Count() == 0)
{
return(document);
}
ArgumentSyntax newIdentifierArg = SyntaxFactory.Argument(SyntaxFactory.IdentifierName(newParameterName));
ArgumentSyntax newNameOfArg = SyntaxFactory.Argument(CreateLiteralForIdentifier(document, newParameterName));
SyntaxNode root = await document.GetSyntaxRootAsync(cancellationToken);
var newRoot = root.ReplaceNode(argumentListNode,
SyntaxFactory.ArgumentList(
SyntaxFactory.SingletonSeparatedList(newIdentifierArg)
.Add(newNameOfArg))
.AddArguments(argumentListNode.Arguments
.Skip(2)
.ToArray()));
return(document.WithSyntaxRoot(newRoot));
}