Incorrect code generation when declaring an observable property with a source-generated type

[Aurumaker72]

Describe the bug

Declaring an observable property with a source-generated type fails at compile-time.

Source generators should have access to other source-generated code.

Steps to reproduce

1. Create a project
2. Add CsWin32
3. Add CommunityToolkit.MVVM
4. Register `WindowFromPoint` in the `NativeMethods.txt` file
5. Add an observable property of type `HWND`
6. `The type or namespace name 'HWND' could not be found ...\SpySharp.Views.WPF.MainWindow.g.cs`

Expected behavior

The project should compile as it does with non-source-generated types.

Screenshots

IDE and version

VS 2022 Preview

IDE version

VisualStudio.17.Preview/17.7.0-pre.2.0+33808.371

Nuget packages

• [ ] CommunityToolkit.Common
• [ ] CommunityToolkit.Diagnostics
• [ ] CommunityToolkit.HighPerformance
• [X] CommunityToolkit.Mvvm (aka MVVM Toolkit)

Nuget package version(s)

8.2.1

Additional context

No response

Help us help you

Yes, but only if others can assist

[Balkoth]

I guess this is an inherent issue with source generators as Source generators cannot see the output of other source generators