When will WinUI 3 support .NET 7's Native AOT Compiler?

[jamers99]

.NET 7 brings native AOT deployment, and I'm personally very excited for it. I would love to be able to use it in our WinUI 3 project.
https://learn.microsoft.com/en-us/dotnet/core/deploying/native-aot/

Is this something we can expect will work eventually? This would be amazing! Right now I can enable it in the project (PublishAot), but errors show up when starting from VS:

1>------ Build started: Project: WinUIPerf, Configuration: Release x64 ------
1>Skipping analyzers to speed up the build. You can execute 'Build' or 'Rebuild' command to run analyzers.
1>WinUIPerf -> C:\Repos\jamers99\public\WinUIPerf\bin\x64\Release\net7.0-windows10.0.19041.0\win10-x64\WinUIPerf.dll
1>Generating native code
1>C:\Users\james\.nuget\packages\microsoft.windows.sdk.net.ref\10.0.19041.28\lib\net6.0\WinRT.Runtime.dll : warning IL2104: Assembly 'WinRT.Runtime' produced trim warnings. For more information see https://aka.ms/dotnet-illink/libraries
1>C:\Users\james\.nuget\packages\microsoft.windows.sdk.net.ref\10.0.19041.28\lib\net6.0\WinRT.Runtime.dll : warning IL3053: Assembly 'WinRT.Runtime' produced AOT analysis warnings.
1>C:\Users\james\.nuget\packages\runtime.win-x64.microsoft.dotnet.ilcompiler\7.0.2\framework\System.Linq.Expressions.dll : warning IL3053: Assembly 'System.Linq.Expressions' produced AOT analysis warnings.
1>C:\Repos\jamers99\public\WinUIPerf\obj\x64\Release\net7.0-windows10.0.19041.0\win10-x64\XamlTypeInfo.g.cs(551): Trim analysis warning IL2059: WinUIPerf.WinUIPerf_XamlTypeInfo.XamlUserType.RunInitializer(): Unrecognized value passed to the parameter 'type' of method 'System.Runtime.CompilerServices.RuntimeHelpers.RunClassConstructor(RuntimeTypeHandle)'. It's not possible to guarantee the availability of the target static constructor.
1>C:\Users\james\.nuget\packages\microsoft.windowsappsdk\1.2.221109.1\lib\net6.0-windows10.0.18362.0\Microsoft.WinUI.dll : warning IL3053: Assembly 'Microsoft.WinUI' produced AOT analysis warnings.
1>   Creating library bin\x64\Release\net7.0-windows10.0.19041.0\win10-x64\native\WinUIPerf.lib and object bin\x64\Release\net7.0-windows10.0.19041.0\win10-x64\native\WinUIPerf.exp
1>C:\Users\james\.nuget\packages\microsoft.windowsappsdk\1.2.221109.1\buildTransitive\Microsoft.Build.Msix.Packaging.targets(1504,5): error APPX1101: Payload contains two or more files with the same destination path 'WinUIPerf.exe'. Source files: 
1>C:\Users\james\.nuget\packages\microsoft.windowsappsdk\1.2.221109.1\buildTransitive\Microsoft.Build.Msix.Packaging.targets(1504,5): error APPX1101: C:\Repos\jamers99\public\WinUIPerf\obj\x64\Release\net7.0-windows10.0.19041.0\win10-x64\apphost.exe
1>C:\Users\james\.nuget\packages\microsoft.windowsappsdk\1.2.221109.1\buildTransitive\Microsoft.Build.Msix.Packaging.targets(1504,5): error APPX1101: C:\Repos\jamers99\public\WinUIPerf\bin\x64\Release\net7.0-windows10.0.19041.0\win10-x64\native\WinUIPerf.exe
1>Done building project "WinUIPerf.csproj" -- FAILED.

[jamers99]

Note that if I try to run the exe in the bin, it doesn't launch, and this error is in the event viewer:

Faulting application name: WinUIPerf.exe, version: 1.0.0.0, time stamp: 0x63beea45
Faulting module name: WinUIPerf.exe, version: 1.0.0.0, time stamp: 0x63beea45
Exception code: 0xc8fabf8e
Fault offset: 0x00000000001d03a9
Faulting process id: 0x0xC8FC
Faulting application start time: 0x0x1D925DDDD6C5C30
Faulting application path: C:\Repos\jamers99\public\WinUIPerf\bin\x64\Release\net7.0-windows10.0.19041.0\win10-x64\native\WinUIPerf.exe
Faulting module path: C:\Repos\jamers99\public\WinUIPerf\bin\x64\Release\net7.0-windows10.0.19041.0\win10-x64\native\WinUIPerf.exe
Report Id: 5d2f828f-c07e-4289-ac4e-85bf79c8bea9
Faulting package full name: 
Faulting package-relative application ID: 

[DarranRowe]

At the moment, the documentation does state that it is only supported in console applications. This is a limitation from .NET 7 itself. There is also limitations with respect to COM, and since the Windows Runtime (which the Windows App SDK/WinUI 3 is built on) is COM with some extras, then this could be causing issues.
So I would say not for a while.

[mklemarczyk]

@DarranRowe so we have 2025, and just released .NET 9 with AOT compilation for old UWP projects.
Any news for WinUI 3 that should be more in development than UWP ?

REF : https://devblogs.microsoft.com/ifdef-windows/preview-uwp-support-for-dotnet-9-native-aot/
REF : https://learn.microsoft.com/en-us/visualstudio/releases/2022/release-notes#desktop

[4OTbIPE]

WinUI3 supports Native AOT since 1.6 release...

[DarranRowe]

Like @4OTbIPE states, it is in the release notes.

It isn't perfect, and there are still issues where generated code isn't marked as AoT compatible, but it is here.