Unresolvable(?) breaking change with System.Linq.Async in net10.0

[Tragetaschen]

Description

I've been trying to apply the suggestions for the expected breaking changes regarding the System.Linq.Async nuget. However, I'm not able to get to a working configuration. Between ToAsyncEnumerable being ambiguous and AnyAwaitAsync seemingly gone.

Reproduction Steps

In a class library referencing System.Linq.Async targeting net9.0 and net10.0, I have these reduced (and now nonsensical) extension methods.

public static class MyExtensions
{
    public static ValueTask<bool> AnyAwaitConcurrent<TSource>(
        this IAsyncEnumerable<TSource> items,
        Predicate<TSource> predicate,
        CancellationToken cancellationToken = default)
      => items.AnyAwaitAsync(x => ValueTask.FromResult(predicate(x)), cancellationToken);

    public static IAsyncEnumerable<T> MyToAsyncEnumerable<T>(this IEnumerable<T> source)
        => source.ToAsyncEnumerable();
}

This code compiles for net9.0

Expected behavior

There are clear migration steps and available APIs for this code to continue to work.

Actual behavior

For net10.0:
As given, it's reporting the documented ambiguous method since .NET 10 now comes with a base class library method, but the documented fixes also break the code.

Since it's a direct reference in a multi-target library, I'm supposed to reference System.Linq.AsyncEnumerable instead. This, however, breaks the call to AnyAwaitAsync since this extension method isn't available in that setup.

Regression?

It's a known breaking change, but the resolution steps are at least unclear. I'm inclined to say:

Yes.

Known Workarounds

There might be a way to call the correct extension methods using assembly aliases, but I have no clue how to declare those with framework assemblies.

Configuration

10.0.100-rc.1.25451.107

Other information

No response

[MihuBot]

I'm a bot. Here are possible related and/or duplicate issues (I may be wrong):

• [dotnet-sdk-10.0.100-preview.1.25103.13] Some apps retarget failed with CS0121 and CS0428 System.Linq errors #112462
• [API Proposal]: Integrate Reactive's System.Linq.Async APIs into the Base Class Libraries #79782

[Tragetaschen]

yup, that has been my reading material for the past 90 minutes 😁

[tannergooding]

Have you tried the workaround given here: #79782 (comment)

@eiriktsarpalis would be the best person to comment on if the improved documentation ended up getting added anywhere.

[Tragetaschen]

Yes.
If I understand it right, this removes the nuget assembly from the compilation if it was brought in via transitive reference. This isn't the case in my example, but has the same effect as removing the direct reference with the same outcome.

[Tragetaschen]

Regarding documentation, it looks like the last questions remained unanswered in the issue
dotnet/docs#44886 (comment)

[stephentoub]

Can you not change your call to AnyAwaitAsync to instead call AnyAsync?

[Tragetaschen]

Unsure. I'm not the original author of the actual extension methods and not fluent in the actual semantics of the System.Linq.Async extensions methods. I need to look into that. That's probably something where the documentation could help a lot...

[stephentoub]

This is an example where the functionality is expected to be the same, it's just that the community project used an undesirable name, and the official library fixed it, so the intent is anywhere you're using AnyAwaitAsync you should instead just be able to use AnyAsync. This is an example of what https://learn.microsoft.com/en-us/dotnet/core/compatibility/core-libraries/10.0/asyncenumerable refers to when it says "some call sites might need updates to refer to newer names and signatures".