Ionide-vscode-fsharp: Can't start FSI

[caxelrud]

For the last few days my VSCode stopped starting the FSI. It was good before.
When using command (Ctrl-P) and ">FSI:Start" I get the following message:
"connect ECONNREFUSED 127.0.0.1:8119"

If I try to mark instructions and send to FSI (for the first time) using Alt-Enter I get the following:
"Failed to send text to FSI"
"Failed to spawn FSI, please ensure it's in PATH"

I tried to reinstall everything including VSCode and Ionide without sucess.

[Bob-McCrory]

I have exactly the same problem on my Surface Book; it started after I installed the October Windows 10 update and a firmware update. I've tried uninstalling and reinstalling VSCode and Ionide several times, but nothing seemed to work. Also put FSI in the PATH, verified it worked using a DOS box, but VSCode/Ionide still can't find it.

[Bob-McCrory]

Oh, one other thing. It all works fine on my Surface Pro 2017, even after the October updates.

[kaareltinn]

It stopped working for me as well after updating VSCode (October updates)

[Gulogomi]

I have the same problem on Ubuntu

[vilinski]

Don't know whether my problem is related to above comments. But it happens to me too by switching Fsac Runtime to netcore on windows (as newly suggested from ionide).
I get following popup:

Failed to start language services. Please check if Microsoft Build Tools 2013 are installed

The suggested MSBuild version is a little obsolete. 😄

My investigations so far:
output from F# Language Service (server):

Running: Aktive Codepage: 65001. C:Usersusername.vscodeextensionsionide.ionide-fsharp-3.28.0/bin_netcore/fsautocomplete.dll --mode http --port 8277 --hostPID=14664
spawn Aktive Codepage: 65001. ENOENT

tried to execute the command in cmd:
> .\fsautocomplete.dll --mode http --port 8277 --hostPID=14664

Unbehandelte Ausnahme: System.IO.FileNotFoundException: Die Datei oder Assembly "System.Runtime, Version=4.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" oder eine Abhängigkeit davon wurde nicht gefunden. Das System kann die angegebene Datei nicht finden.

googled for not found System.Runtime. Here someone suggests to execute a dll with dotnet command.
This worked for me finally in cmd:

> dotnet ./fsautocomplete.dll --mode http --port 8277 --hostPID=14664

[11:52:35 INF] tracking host PID 14664
[11:52:35 INF] Smooth! Suave listener started in 341,166ms with binding 127.0.0.1:8277

Should be probably also an easy fix in ionide then if dotnet is in path.

Windows 10
dotnet 2.1.403
ionide 3.28.0

[Teddmab]

Got the same issue on my Ubuntu
Distributor ID: Ubuntu
Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial

I finally fixed it, but I'm not sure if what I did fixed it or not.

Anywyas, here is what I did:

1. in cmd, type which fsharpi to get the fsi path
2. in VS Code, go to File > Preferences > Settings > Extensions > Fsharp configruation
3. Fsharp:Fsi File Path and enter the result you got with which fsharpi
4. uninstall ionide-fsharp from VS Code extension > reload > reinstall

But this solution fixed the execution of the script but error syntax highlighting and code lens is not working.

[Bob-McCrory]

I don't know if this will help or not. On my Surface Book running Windows 10, when I set the path for fsi in the preferences, when I try to run an F# script through the interpreter I get the following error message:

The terminal process command '"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\CommonExtensions\Microsoft\FSharp\fsi.exe" --fsi-server-input-codepage:65001' failed to launch (exit code: 2)

Any thoughts, anyone? Thanks.

[Bob-McCrory]

OK. A little progress. I had thought the fsi path needed to be in JSON format. When I don't put the path in quotes and use single backslashes, I can get the interpreter to run. However, while I have auto complete, I don't have Intellisense. Any suggestions?

[caxelrud]

I installed .NET Core SDK. It is working now.

[Bob-McCrory]

After the latest VSCode update, Ionide now seems to be working properly.