Failed to AOT compile aot-instances.dll, the AOT compiler exited with code 134

[smoogipoo]

Description

Hi.

We're upgrading our iOS project from .NET 8 to .NET 10 and we're encountering the following error:

* Assertion at /Users/runner/work/1/s/src/runtime/src/mono/mono/mini/method-to-ir.c:4916,
  condition `is_ok (cfg->error)' not met, function:inline_method, 
  Field not found: !2 osu.Framework.Graphics.Transforms.Transform`3.<Target>k__BackingField
  Due to: Could not find field in class

18:23:00.910   1:7>/Users/smgi/.dotnet/packs/Microsoft.iOS.Sdk.net10.0_26.5/26.5.10284/targets/Xamarin.Shared.Sdk.targets(1523,3):
  error : Failed to AOT compile aot-instances.dll, the AOT compiler exited with code 134. [/Users/smgi/Repos/osu-framework/SampleGame.iOS/SampleGame.iOS.csproj]

The error occurs here: https://github.com/ppy/osu-framework/blob/8afe8a5ea4489019bab0978274383865971b1141/osu.Framework/Graphics/Transforms/Transform.cs#L105-L107

• Build passes when the relevant code is extracted to an isolated project.
• Build fails after removing all references to Target but leaving the property in place.
• Build fails after applying [MethodImpl(NoInlining)] to the property.
• Build passes after transforming the property to a field.

Of note, the Easing property highlighted by the above perma link also exhibits the same behaviour in all cases. So for example when I say "transforming the property to a field", I mean transforming both of those properties

I'm at a loss how to debug this further.

Reproduction Steps

1. Clone + checkout smoogipoo/osu-framework@37cd1e8
2. Navigate to SampleGame.iOS
3. Run dotnet publish -r ios-arm64

Expected behavior

The build to complete successfully.

Actual behavior

The build fails with the error above.

Regression?

This previously worked on .NET 8.

Known Workarounds

The build passes when the interpreter is used.

Configuration

$ dotnet --info
.NET SDK:
 Version:           10.0.300
 Commit:            caa81fa497
 Workload version:  10.0.301.1
 MSBuild version:   18.6.3+caa81fa49

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  26.3
 OS Platform: Darwin
 RID:         osx-arm64
 Base Path:   /Users/smgi/.dotnet/sdk/10.0.300/

.NET workloads installed:
 [ios]
   Installation Source: SDK 10.0.300
   Manifest Version:    26.5.10284/10.0.100
   Manifest Path:       /Users/smgi/.dotnet/sdk-manifests/10.0.100/microsoft.net.sdk.ios/26.5.10284/WorkloadManifest.json
   Install Type:        FileBased

 [android]
   Installation Source: SDK 10.0.300
   Manifest Version:    36.1.69/10.0.100
   Manifest Path:       /Users/smgi/.dotnet/sdk-manifests/10.0.100/microsoft.net.sdk.android/36.1.69/WorkloadManifest.json
   Install Type:        FileBased

Configured to use workload sets when installing new manifests.

Host:
  Version:      10.0.8
  Architecture: arm64
  Commit:       94ea82652c

.NET SDKs installed:
  8.0.421 [/Users/smgi/.dotnet/sdk]
  10.0.300 [/Users/smgi/.dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 8.0.27 [/Users/smgi/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 10.0.8 [/Users/smgi/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 8.0.27 [/Users/smgi/.dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 10.0.8 [/Users/smgi/.dotnet/shared/Microsoft.NETCore.App]

Other information

No response

[dotnet-policy-service]

Tagging subscribers to 'os-ios': @vitek-karas, @kotlarmilos, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[vitek-karas]

Here's a much smaller repro - still relies on the larger project from the original repro, but it's shorter to build at least:
https://gist.github.com/vitek-karas/b1913bd0b3667145b379c0ae9e4cf6f5

As for root cause - not sure yet, it is very likely a break from .NET 8 caused by #91261. It's also very likely not a trimming problem, but AOT compiler problem.

[vitek-karas]

Reopening - the issue should be closed when the #129804 backport to .NET 10 is merged.