TypeInitializationException in PointCollection regression in 0.8.2

[Marv51]

Describe the bug
Crashing exception in PointCollection introduced in 0.8.2

Steps to reproduce the bug

var pc = new PointCollection();

Adding this line to an empty WinUI 3 desktop project results in an exception:
System.TypeInitializationException: The type initializer for '<SignatureCache>System.Collections.Generic.IList'1<Windows.Foundation.Point>' threw an exception.'

With inner exception:
TypeLoadException: Could not load type 'ABI.Windows.Foundation.Point' from assembly 'Microsoft.WinUI, Version=3.0.0.0, Culture=neutral, PublicKeyToken=de31ebe4ad15742b'.

Stack Trace

   at <GuidPatcherImplementationDetails>.<IIDData>System.Collections.Generic.IList`1<Windows.Foundation.Point>()
   at Microsoft.UI.Xaml.Media.PointCollection..ctor(IObjectReference objRef)
   at Microsoft.UI.Xaml.Media.PointCollection..ctor()
   at App12.MainWindow.myButton_Click(Object sender, RoutedEventArgs e) in C:\Users\Marvin\source\repos\App12\App12\MainWindow.xaml.cs:line 34
   at WinRT._EventSource_global__Microsoft_UI_Xaml_RoutedEventHandler.EventState.<GetEventInvoke>b__1_0(Object sender, RoutedEventArgs e)
   at ABI.Microsoft.UI.Xaml.RoutedEventHandler.<>c__DisplayClass10_0.<Do_Abi_Invoke>b__0(RoutedEventHandler invoke)
   at WinRT.ComWrappersSupport.MarshalDelegateInvoke[T](IntPtr thisPtr, Action`1 invoke)
   at ABI.Microsoft.UI.Xaml.RoutedEventHandler.Do_Abi_Invoke(IntPtr thisPtr, IntPtr sender, IntPtr e)

Version Info

NuGet package version:
WinUI 3 - Windows App SDK 0.8: 0.8.2
Was working in 0.8.1

Windows app type:

UWP	Win32
	Yes

Windows version	Saw the problem?
Insider Build (xxxxx)
21H1 (19043)	Yes
October 2020 Update (19042)
May 2020 Update (19041)
November 2019 Update (18363)
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

Additional context
Clear regression, most likely CsWinRT related. Impact: Crash on launch, blocks us completely.

[Marv51]

Sorry for posting unfinished issue at first, GitHub submitted prematurely.

@anawishnoff Any chance you could add 21H1 (19043) to the Windows version table in the issue template? Having to add that row manually every time for the current public release is getting a bit old at this point.

[marcelwgn]

@Marv51 Created microsoft/microsoft-ui-xaml#5693 to fix the missing OS version :)

[llongley]

@Scottj1s Possible C#/WinRT projection issue?

[Marv51]

Looks very much like a regression in #849. However, setting CsWinRTIIDOptimizerOptOut on the consuming app did not resolve the exception.

[Scottj1s]

Setting CsWinRTIIDOptimizerOptOut won't help here - the problem is in Microsoft.WinUI.dll (WinUI 3 projection assembly).

The IIDOptimizer should be rewriting the type reference to ABI.Windows.Foundation.Point as coming from winrt.runtime.dll, not Microsoft.WinUI.dll

[Marv51]

@j0shuams Did you already have a chance to look at this? Are you able to reproduce the crash?

This issue is very important for me as it makes the Microsoft.UI.Xaml.Shapes.Polygon class in WinUI unusable. Unfortunately, my app uses polygons in quite a few critical places.

[j0shuams]

@Marv51 Hi, I have just returned from vacation and am starting in on this. Thanks for your patience.