The caracteristic "Missing Importations detection" is not available due to an internal error.

[vsfeedback]

The caracteristic "Missing Importations detection" is not available due to an internal error.

[CyrusNajmabadi]

This looks like some sort of authoring bug or setup bug. Given that we're not hearing about it from anyone else, i'm going to close this out as not a roslyn issue. I'm going to reactive the devcom issue and give to the servicehub guys to see if it's something they might know about. IT's similar to the issue i had where old servicehub .net binaries were on disk, and they were being innapropriately loaded, causing package load failures. Maybe it's the exact same issue. will give to them to find out.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[sharwell]

The missing method was added in this pull request:
dotnet/runtime#86210

The change should be present in System.Collections.Immutable 8.0.0 Preview 5 and newer. It appears that this user is hitting a case where a different (lower) version of the assembly is getting loaded for ServiceHub scenarios.

[sharwell]

My recommendation is to disable the following option:
Tools → Options... → Text Editor → C# → Advanced → Run code analysis in separate process

This will provide a workaround for the above issue in addition to, in my consistent experience for the past several years, providing a marked improvement in overall IDE and system performance.