I am not able to reproduce the issue on .NET 9.

Do you have <IlcDisableReflection>true</IlcDisableReflection> property set in your project by a chance? Setting this experimental property would result into behavior that you are seeing. This experimental property does not exist anymore.

Nope, my full csproj looks like this:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net9.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <PublishAot>true</PublishAot>
    <InvariantGlobalization>true</InvariantGlobalization>
    <PublishTrimmed>true</PublishTrimmed>
    <JsonSerializerIsReflectionEnabledByDefault>true</JsonSerializerIsReflectionEnabledByDefault>
  </PropertyGroup>

</Project>

So it is possible to get enum value/names in AOT in at least some configuration?

It's possible my linux setup is bit Frankenstein-ish... I had some difficulty getting dotnet 9 on my Linux Mint since it wasn't offered by the standard software repos yet...

Are you (joktas) actually running on Linux?

Maybe I'll try following my own steps from scratch to see if I have any better luck. I am using a much bigger project than what I posted.

test62.tar.gz

Well, when I start from nothing and just do the simple test, it in fact works for me too!
I'm attaching my 'bad' project to this -- I will see if I can pinpoint what about it causes the enum parsing to not work. My enums have custom attributes on them, not sure if that's the problem yet or not.

In this, my program.cs has var a =Enum.GetValues<Color>(); on line 16 that is crashing. (But only in Release AOT) The exception stack trace doesn't offer line #s but I've done enough adjusting that I'm very sure that is the offending line.

Ok, I think I figured it out. So if my enum has a generic attribute on it, that's when it doesn't work. "Normal" attributes are fine... I'm not sure what about generic attributes causes the problem, but here is a simple example that fails:

foreach (var e in Enum.GetValues<Color>())
  Console.WriteLine(e);

[CustomAttribute<int>]
enum Color { R, Y, G, B }

internal class CustomAttribute<T> : Attribute
{
}

(At first I thought maybe it was the self-referential types in my attachment above, but it doesn't seem to matter what the argument type is)

I was looking for an easy-ish way to mark my enums in a way that I could automatically-ish get the names and values to make sure they will match up with with remote instances of other programs running. I'll see if I can find one that doesn't involve generic attributes.

It seems that we didn't handle TypeSpecification here:

/cc: @MichalStrehovsky