Description

In the HostApp.cs project, SourceGen is enabled. When running Bugzilla39636, it throws a TargetInvocationException on Mac
https://github.com/dotnet/maui/blob/main/src/Controls/tests/TestCases.HostApp/Issues/Bugzilla/Bugzilla39636.xaml

"In OnPlatform, the MacCatalyst value is not defined, so it should take the default value of 0. But when SourceGen is enabled, it doesn't seem to recognize the default value and throws an exception. Without SourceGen, it works properly without any exceptions

With SourceGen in HostApp.

Without SourceGen in HostApp

Steps to Reproduce

Sample : https://github.com/dotnet/maui/blob/main/src/Controls/tests/TestCases.HostApp/Issues/Bugzilla/Bugzilla39636.xaml

Link to public reproduction project repository

No response

Version with bug

10.0.10

Is this a regression from previous behavior?

No, this is something new

Last version that worked well

No response

Affected platforms

macOS

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output