Type of issue

Outdated article

Description

The recommended action here describes how you should use csproj exclusions to avoid System.Linq.Async exclusions.

Endjin released a new version of said package that will get rid of the conflicts in most cases automatically. Just need to upgrade it.

https://endjin.com/blog/2025/11/ix-v7-dotnet-10-linq-iasyncenumerable

If you've been seeing errors of this kind since .NET 10 shipped:

error CS0121: The call is ambiguous between the following methods or properties: 'System.Linq.AsyncEnumerable.Select<TSource, TResult>(System.Collections.Generic.IAsyncEnumerable<TSource>, System.Func<TSource, TResult>)' and 'System.Linq.AsyncEnumerable.Select<TSource, TResult>(System.Collections.Generic.IAsyncEnumerable<TSource>, System.Func<TSource, TResult>)'

you may need to upgrade to v7 of Ix.NET's System.Linq.Async package. (In the long run you will want to stop using it entirely, and use the .NET runtime library System.Linq.AsyncEnumerable package instead, but if you've ended up seeing these errors because of an indirect dependency, you might not be able to remove the reference just yet, in which case you'll need to upgrade it instead.)

In most cases, that will solve the problem. It's possible you'll also need to add a reference to System.Interactive.Async v7 (or upgrade an existing reference to that version). There are also some more complex scenarios. This post explains what has changed and why.

Page URL

https://learn.microsoft.com/en-us/dotnet/core/compatibility/core-libraries/10.0/asyncenumerable

Content source URL

https://github.com/dotnet/docs/blob/main/docs/core/compatibility/core-libraries/10.0/asyncenumerable.md

Document Version Independent Id

cabe10bd-a192-2e9f-df66-1d7b82fdc28d

Platform Id

d72d0082-d90a-24e4-a73a-38c2d7696252

Article author

@gewarren

Metadata

• ID: 6bdd8cc4-3759-655d-bd5d-3599858b7a51
• PlatformId: d72d0082-d90a-24e4-a73a-38c2d7696252
• Service: dotnet-fundamentals

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