async Task <Document> ToRefAsync(Document document, ForEachStatementSyntax forEachStatementSyntax, bool isReadOnly, CancellationToken cancellationToken)
{
var newForEachStatementSyntax = forEachStatementSyntax.ToRef(isReadOnly);
var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
if (root is null)
{
throw new NullReferenceException();
}
root = root.ReplaceNode(forEachStatementSyntax, newForEachStatementSyntax);
return(document.WithSyntaxRoot(root));
}