Can I use Roslyn in .Net standard 2.0? Nuget package Microsoft.CodeAnalysis.CSharp is only for .Net Framework. Are there any other ways?
Look at the second point under Details section on github announcement. Personally, I already tried referencing v2.3.0 analyzer assemblies in netstandard 2.0 library and it worked (though admittedly I run it on full framework in the end).
Try it and you will see if it works in your case. If not, wait for official support or raise an issue.