v7.21.0 is causing intellisense issues in VS code

[fwaris]

Just upgraded to v7.21.0.

Seeing red squiggles in files that should compile fine.
Hovering over a squiggle gives 'index out of bounds' error message.

Fixed by going back to v7.20.3

Running Window 11 with the following sdks installed

C:\Users\Faisa>dotnet --list-sdks
6.0.416 [C:\Program Files\dotnet\sdk]
8.0.301 [C:\Program Files\dotnet\sdk]
8.0.400 [C:\Program Files\dotnet\sdk]

[vzarytovskii]

A stacktrace would be helpful, to understand if it happens in FSAC or FCS.

[vzarytovskii]

This is how it looks:

And also this:

I have no stacktrace at this point.

[kant2002]

For the record. There no logs anywhere to be found. Even after enabling

"FSharp.verboseLogging": true,
"FSharp.trace.server": "verbose",

It appear to me when developing using Oxpecker library, and when I modify computation expression. It's hard to reproduce for now. so does computatoin expression is the culprit is speculative.

[vzarytovskii]

Likely suspect is https://github.com/dotnet/fsharp/pull/17096/files which uses HashMultiMap as an underlying structure, which is not threadsafe.

[fwaris]

With the latest version -v7.21.1 - there are some issues still remaining - prob. related to the same fix.

When I edit a file, sometimes I get red squiggles.
The error is (when hovering over the squiggles):

internal error: Operations that change non-concurrent collections must have exclusive access. A concurrent update was performed on this collection and corrupted its state. The collection's state is no longer correct. F# Compiler[193](https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/compiler-messages/fs0193)

[vzarytovskii]

With the latest version -v7.21.1 - there are some issues still remaining - prob. related to the same fix.

When I edit a file, sometimes I get red squiggles.

The error is (when hovering over the squiggles):

internal error: Operations that change non-concurrent collections must have exclusive access. A concurrent update was performed on this collection and corrupted its state. The collection's state is no longer correct. F# Compiler[193](https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/compiler-messages/fs0193)

This should've been fixed in FCS already. Are there any examples of code, or stack trace?

[TheAngryByrd]

This should've been fixed in FCS already

@vzarytovskii was this released in a nuget package yet?

[baronfel]

We're using the 8.0.400 build - did the fix come out after?

[vzarytovskii]

We're using the 8.0.400 build - did the fix come out after?

Yes, not in 8 branch though, we didn't backport it there

[baronfel]

Ok, so FSAC updating to https://www.nuget.org/packages/FSharp.Compiler.Service/43.9.100-preview.24422.2 or similar should unblock this.

[baronfel]

I suppose now that RC1 is out we should probably look at doing this anyway.

[vzarytovskii]

Yeah, there are whole bunch of fixes there. Should be fine despite it being a "preview".