Hi everyone,

I've just upgraded my site from Umbraco 10.7 to 10.8.2 and everything's working correctly, except for my Site Map page. When I open it, I get the following error:

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context. Auto-generated code requires an explicit '#nullable' directive in source.

void Traverse(IPublishedContent? node)

My .cshtml file is as follows. As you can see, this is similar to the snippet provided with Umbraco:

@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage
@using Umbraco.Cms.Core
@using Umbraco.Cms.Core.Models.PublishedContent
@using Umbraco.Cms.Core.Routing
@using Umbraco.Extensions

@inject IPublishedValueFallback PublishedValueFallback
@inject IPublishedUrlProvider PublishedUrlProvider
@*
    This snippet makes a list of links of all visible pages of the site, as nested unordered HTML lists.

    How it works:
    - It uses a local method called Traverse() to select and display the markup and links.
*@

@{
    var selection = Model.Root();
}

<div class="sitemap">
    @* Render the sitemap by passing the root node to the traverse method, below *@
    @{
        Traverse(selection);
    }
</div>

@* Helper method to traverse through all descendants *@
@{
    void Traverse(IPublishedContent? node)
    {
        //Update the level to reflect how deep you want the sitemap to go
        var maxLevelForSitemap = 5;

        @* Select visible children *@
        var selection = node?.Children.Where(x => x.IsVisible(PublishedValueFallback) && x.Level <= maxLevelForSitemap).ToArray();

        @* If any items are returned, render a list *@
        if (selection?.Length > 0)
        {
            <ul class="sitemap">
                @foreach (var item in selection)
                {
                    <li class="[email protected]">
                        <a href="@(item.IsDocumentType("Faq") ? (item.Level == 4 ? item.Parent.Url(PublishedUrlProvider) + "#a" + item.Id : item.Parent.Parent.Url(PublishedUrlProvider) + "#a" + item.Id) : item.Url(PublishedUrlProvider))">@item.Name</a>

                        @* Run the traverse helper again for any child pages *@
                        @if (!item.IsDocumentType("BusRoute"))
                        {
                            Traverse(item);
                        }
                    </li>
                }
            </ul>
        }
    }
}

I've tried putting #nullable enable before the Traverse method (and also right at the start of the file), but it doesn't help. I also have <Nullable>enable</Nullable> in my .csproj file.

Does anyone have any idea what's going on here? It worked fine under 10.7 and I don't see any breaking changes in 10.8 that could explain this. Help! :)