Obsolete AutomationProperties properties cause XamlC exception on NET 8

[GalaxiaGuy]

Description

Using AutomationProperties.Name or AutomationProperties.Hint (and I would guess the other deprecated AutomationProperties attached properties) inside a DataTemplate in a control's Resources generates the error XamlC error : Object reference not set to an instance of an object. at compile time.

I'm in the process of porting a large app. It previously worked against .NET 7 and did not see this issue.

Steps to Reproduce

Add something like the following to a XAML file:

    <ContentPage.Resources>
        <DataTemplate x:Key="Template">
            <Image
                Source="dotnet_bot.png"
                AutomationProperties.Name="Cute dot net bot waving hi to you!"
                HeightRequest="200"
                HorizontalOptions="Center" />        
        </DataTemplate>
    </ContentPage.Resources>

Link to public reproduction project repository

https://github.com/GalaxiaGuy/MauiBugs/tree/main

Version with bug

8.0.0-preview.1.7762

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI, Yes, this used to work in Xamarin.Forms

Last version that worked well

7.0.92

Affected platforms

iOS, Android

Affected platform versions

No response

Did you find any workaround?

Updating the properties to the correct SemanticProperties equivalents allows the project to compile. It took some trial and error to work out what was causing the problem though.

Relevant log output

No response

[samhouts]

The AutomationProperties were obsoleted in #13104, which released in 8.0.0-preview.1.7762. I think it's technically not a regression in XamlC (it probably always had the behavior of blowing up on now non-existent attached properties), but it does need to have a better error message.

[StephaneDelcroix]

there is a LogWarning, but it looks like it's throwing anyway