Linter not available

[isaacabraham]

Describe the bug

The FSLint integration appears to be broken. No lint warnings appear, although I have ensured that the linter is turned on.

Steps to reproduce

1. Create an FSX (or FS) file.
2. Make a lint warning e.g. let x = [ 1 .. 10 ] |> List.map id |> List.map id
3. A lint warning should appear, but nothing does.

I've tested with the dotnet FS Lint tool and that still works.

Machine info

• OS: Windows
• .NET SDK version: 5.0.202
• Ionide version: 5.5.3

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[baronfel]

Yep! Fsharplint integration has been disabled for about a month now, because that project is behind in its support for FCS 39. There is an open PR, but it has languished for a bit. It's the same root problem as with FAKE: tight integrations require upkeep, and if we can't keep those integrations up to date it's a judgement call if it's worth keeping the entire application (including FCS perf/bugfixes/etc) held back for that.

[baronfel]

Longer term, it would be ideal to have these sorts of integrations as an out-of-process model, and we might look in that direction with fantomas leading the way, but out-of-process also implies another, not-shared FSharpChecker instance which could have negative impacts on memory usage.

[faldor20]

@baronfel I think there is an argument to be made for being very conservative as far as removing large features. This effects a huge number of people very negatively. If I was just coming to F# and I discovered it's primary IDE plugin didn't even have linting..... well I'd use C# and never look back.

[baronfel]

That certainly an option! The difference here as issues to C# primary comes down to linting and this tooling being OSS only, not MS-backed as they are for C#. That naturally means that available effort is limited. As such, I have to prioritize remaining compatible with language features as they are released, or stagnating.

I choose to stay up to date with new compiler releases, while sending what updates I can to projects I do not directly control for external features. This strikes the best balance in my opinion, using the limited resources at my disposal.

[faldor20]

AHH I wasn't aware there had been a significant change to the language spec. I agree that not supporting current language features is a serious issue in its own right.

I am very sorry for my undue criticism. You clearly have a difficult choice to make and I very much thank you for making it :). Keep up the great work :)

Would it maybe be worth looking at https://github.com/fsprojects/fsharp-language-server which does have working (though less sophisticated) linting or at least mentioning it somewhere along with a acknowledgment that linting is broken?

[MangelMaxime]

@faldor20 I think fsharp language server kind of offer the same level of linting as Ionide as it is not using FSharpLint in it. They display the hint coming from the F# compiler.

Also, fsharp language server is a bit behind Ionide in term of language features. There is a PR open fsprojects/fsharp-language-server#93 to upgrade it to the latest version of FCS at the time of the PR.

[faldor20]

@MangelMaxime I know there was some discussion about merging the two projects. Yes it definitely doesn't cover the same features but it is many times faster and is much more reliable. I find big or complicated projects often just result in fsac throwing errors or working glacially slowly. I recently tried using the typeshape library it was agony. I assume it was related to reflection and generics and stuff but fsac just completely stopped. Had to switch to fsharp language server.

[seanamos]

It looks like FSharpLint has now been updated with version v0.19.0.

[baronfel]

yep! I've got a branch locally where I'm trying to update and reenable the tests. I've run into a couple issues though.