Error: Could not start language service: undefined with 0.7.0 on VSCode 1.4.0

[PlagueHO]

I get the following error when starting VSCode after installing the VSCode-PowerShell 0.7.0 extension in VSCode 1.4.0:

This is running on a Windows 7 machine. Other members of my Dev team have the same issue.

The plugin (0.7.0) works fine on VSCode-Insiders v1.5.0.

[daviwil]

Hey Daniel, is this PowerShell v2 or v3 running on Windows 7? We currently don't support PS v2.

Strange that VS Code 1.4 vs 1.5 Insiders would make a difference, it shouldn't have an impact... Is this on the same machine?

[PlagueHO]

Hi @daviwil - It's PS4.0 on Windows 7.0. It is strange.

It works fine on VSCode 1.3.1 (I downgraded to confirm). I couldn't see any reason for this either. I'm just using the insiders build now anyway, so I'm not too worried. Thought it was worth reporting though.

[daviwil]

Apparently there's some sort of issue in VS Code 1.4 that didn't show up until now. Bizarre! I think I've seen someone else with a similar error, I wonder if they've been affected by this one as well.

At any rate, thanks a lot for confirming which VS Code versions it was happening with! I'll keep the bug open for now to track this.

[PlagueHO]

I was mistaken about it working on VSCode Insiders 1.5.0-insiders. It has the same problem on that version. I was mistaken because I hadn't yet clicked a PS1 file (only XML and MD files) so thought it worked. So same error is 1.5.0-insiders. Sorry about that.

[daviwil]

Hmmm OK, so maybe there is something different in the later VS Code builds that's causing this. Thanks, I'll keep an eye out for that!

[MoreThanHidden]

Just confirming it doesn't work on VSCode 1.3.1 or 1.4.0, also this looks to be a duplicate of #253
edit: Downgraded to vscode-powershell 0.6.0 and is working on Windows 7

[PlagueHO]

@MoreThanHidden - good point about the duplicate. I note that #253 has the exact same configuration as I do:
Windows 7 x64, PS4.0

On all my Windows 10 machines this plugin and VSCode combo works just fine. Seems like it might be a Win7 or PS4.0 specified issue.

[ChadThomsen]

I am the someone else with this issue. I have the same setup as PlagueHO does and have the exact same issue.

[derfischi]

The error results from syntax used that is only available in PS5.0 I guess.

e.g. in .vscode\extensions\ms-vscode.PowerShell-0.7.0\scripts\Start-EditorServices.ps1 the ::new Syntax is used throughout the whole file.

$tcpListener = [System.Net.Sockets.TcpListener]::new($ipAddress, $portNumber);

instead of

$tcpListener = New-Object System.Net.Sockets.TcpListener($ipAddress, $portNumber);

And that makes the whole extension crash.

[derfischi]

After replacing all lines that use the ::new Syntax with New-Object, I get the following error in the logs:

powershell.exe started --
pid: 10124
exe: C:\WINDOWS\Sysnative\WindowsPowerShell\v1.0\powershell.exe
bundledModulesPath: C:\Users\10490184.vscode\extensions\ms-vscode.PowerShell-0.7.0\modules
args: C:\Users\10490184.vscode\extensions\ms-vscode.PowerShell-0.7.0\scripts\Start-EditorServices.ps1 -EditorServicesVersion "0.7.0" -HostName "Visual Studio Code Host" -HostProfileId "Microsoft.VSCode" -HostVersion "0.7.0" -BundledModulesPath "C:\Users\10490184.vscode\extensions\ms-vscode.PowerShell-0.7.0\modules" -LogLevel "Normal" -LogPath "C:\Users\10490184.vscode\extensions\ms-vscode.PowerShell-0.7.0\logs\1471957260-EditorServices.log"

ERROR: Add-Type : Unable to load one or more of the requested types. Retrieve the
LoaderExceptions property for more information.
ERROR: In C:\Users\10490184.vscode\extensions\ms-vscode.PowerShell-0.7.0\modules\Powe
rShellEditorServices\PowerShellEditorServices.psm1:2 Zeichen:5

• Add-Type -Path 
  

  "$PSScriptRoot/bin/Desktop/Microsoft.PowerShell.EditorService ...

    + CategoryInfo          : NotSpecified: (:) [Add-Type], ReflectionTypeLoad 
   Exception
    + FullyQualifiedErrorId : System.Reflection.ReflectionTypeLoadException,Mi 
   crosoft.PowerShell.Commands.AddTypeCommand

OUTPUT: {"debugServicePort":16727,"status":"started","channel":"tcp","languageServicePort":13997}
Connecting to port: 13997

The LoaderExceptions property gives me the following:

Could not load type 'System.Management.Automation.Language.AstVisitor2' from assembly 'System.Management.Automation,
Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.

[daviwil]

Thanks guys, I've already worked out all the issues in the PowerShell files but there is one more issue I need to take care of in the C# code for the language service. Putting that together now; if it works I'll ship an update in a few hours.

Thanks for your patience!

[rkeithhill]

@daviwil Check you email. There is one other minor fix I'd like to get in there.

[daviwil]

Ok, got things working again on Win7 with PSv3! Going to prepare a pull request and try to get a release prepared shortly.