User defined compound assignment operators support in LINQPad9(that introduced in .NET 10 preview 5)

sdflysha

https://github.com/dotnet/core/blob/main/release-notes/10.0/preview/preview5/csharp.md
https://github.com/dotnet/csharplang/blob/main/proposals/user-defined-compound-assignment.md

Current behavior:

JoeAlbahari

The Roslyn libraries have been refreshed to the latest daily build in 9.1.5, so this should now work.