Code completion doesn't recognize attributes

[bamarsha]

Describe the bug

After typing @, typing a letter or pressing Ctrl+Space shows completions for all identifiers and keywords, not just attribute names.

To Reproduce

Steps to reproduce the behavior:

1. Open a Q# file in Visual Studio Code.

2. Type @r in a namespace:

   namespace Example {
       @r
   }

3. Code completion shows identifiers that aren't valid as attributes, like the repeat keyword.

Expected behavior

Code completion should only valid attribute names. It is probably easier to show all user-defined types instead of only user-defined types with the @Attribute() attribute, since I don't think code completion is capable of filtering by attributes right now.

Screenshots

System information

• QDK extension v0.12.20092803
• Windows 10, .NET Core 3.1.401
• Visual Studio Code version 1.49.2

Additional context

CodeCompletion\FragmentParsing.fs is probably a good place to start. The modifiers parser can parse things that appear before a declaration, like the internal keyword. It should be possible to also parse the @ symbol here followed by a user-defined type name.

qsharp-compiler/src/QsCompiler/TextProcessor/CodeCompletion/FragmentParsing.fs

Lines 25 to 27 in edc3d15

	/// Parses a declaration modifier list.
	let private modifiers =
	expectedKeyword qsInternal

[ashwinpilgaonkar]

Hi @SamarSha, is it okay if I attempt to fix this?

[bamarsha]

Hi @ashwinpilgaonkar, yes, feel free to start working on this! Let me know if you have any questions.

[ashwinpilgaonkar]

@SamarSha sure will do, thanks.

[ashwinpilgaonkar]

Hi @SamarSha, I seem to be having some trouble with installing the development VSIX extension.

I took the following steps to setup my development environment as per the docs:

1. Installed vsce globally using npm
2. Cloned the project and ran bootstrap.ps1
3. Followed the steps to build a self-contained version of the language server using dotnet publish
4. Ran vsce package to produce an installable VSIX
5. Attempted to install the generated VSIX file into VS Code using Local Extension Installer by Edgar Geier

The module activation fails and gives the following error:

[2020-10-05 17:22:09.679] [exthost] [info] ExtensionService#_doActivateExtension quantum.quantum-devkit-vscode {"startup":false,"extensionId":{"value":"quantum.quantum-devkit-vscode","_lower":"quantum.quantum-devkit-vscode"},"activationEvent":"onLanguage:qsharp"}
[2020-10-05 17:22:09.679] [exthost] [info] ExtensionService#loadCommonJSModule file:///c:/Users/ashpi/.vscode/extensions/quantum.quantum-devkit-vscode-0.9999.20102010/out/extension
[2020-10-05 17:22:09.701] [exthost] [error] Activating extension quantum.quantum-devkit-vscode failed due to an error:
[2020-10-05 17:22:09.703] [exthost] [error] Error: Cannot find module 'vscode-extension-telemetry'
Require stack:
- c:\Users\ashpi\.vscode\extensions\quantum.quantum-devkit-vscode-0.9999.20102010\out\telemetry.js
- c:\Users\ashpi\.vscode\extensions\quantum.quantum-devkit-vscode-0.9999.20102010\out\extension.js
- c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\loader.js
- c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\bootstrap-amd.js
- c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\bootstrap-fork.js
	at Function.Module._resolveFilename (internal/modules/cjs/loader.js:844:17)
	at Module._load (internal/modules/cjs/loader.js:737:27)
	at Function.Module._load (electron/js2c/asar.js:769:28)
	at Function.t._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1046:268)
	at Function.i._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1015:981)
	at Function.n._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1012:303)
	at Module.require (internal/modules/cjs/loader.js:899:19)
	at n (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\loader.js:16:135)
	at Object.<anonymous> (c:\Users\ashpi\.vscode\extensions\quantum.quantum-devkit-vscode-0.9999.20102010\out\telemetry.js:7:38)
	at Module.o._compile (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\loader.js:16:360)
	at Object.Module._extensions..js (internal/modules/cjs/loader.js:1051:10)
	at Module.load (internal/modules/cjs/loader.js:862:32)
	at Module._load (internal/modules/cjs/loader.js:774:14)
	at Function.Module._load (electron/js2c/asar.js:769:28)
	at Function.t._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1046:268)
	at Function.i._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1015:981)
	at Function.n._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1012:303)
	at Module.require (internal/modules/cjs/loader.js:899:19)
	at n (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\loader.js:16:135)
	at Object.<anonymous> (c:\Users\ashpi\.vscode\extensions\quantum.quantum-devkit-vscode-0.9999.20102010\out\extension.js:16:21)
	at Module.o._compile (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\loader.js:16:360)
	at Object.Module._extensions..js (internal/modules/cjs/loader.js:1051:10)
	at Module.load (internal/modules/cjs/loader.js:862:32)
	at Module._load (internal/modules/cjs/loader.js:774:14)
	at Function.Module._load (electron/js2c/asar.js:769:28)
	at Function.t._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1046:268)
	at Function.i._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1015:981)
	at Function.n._load (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1012:303)
	at Module.require (internal/modules/cjs/loader.js:899:19)
	at require (internal/modules/cjs/helpers.js:74:18)
	at Function.s [as __$__nodeRequire] (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\loader.js:33:604)
	at p._loadCommonJSModule (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:1017:241)
	at p._doActivateExtension (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:915:625)
	at p._activateExtension (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:914:708)
	at Object.actualActivateExtension (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:912:453)
	at h._activateExtension (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:644:731)
	at c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:644:409
	at Array.map (<anonymous>)
	at h._activateExtensions (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:644:397)
	at h.activateById (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:642:207)
	at p._activateById (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:913:363)
	at p.$activate (c:\Users\ashpi\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:922:391)
	at processTicksAndRejections (internal/process/task_queues.js:94:5)

I even tried to globally install vscode-extension-telemetry using npm but it doesn't seem to solve the problem.

I haven't received any errors at any of the other steps.
I'm running the latest version Windows 10 (64-bit), VS Code and .NET Core.

I'm unable to figure out why this is happening. Is there something I'm missing?

[bamarsha]

It looks like the same error is affecting the latest release of the QDK extension for VS Code, actually, so it seems like it is a separate issue that we will hopefully have a fix for soon. However, for some reason it doesn't affect me when I build the VSIX using vsce package - the extension seems to work when I install it.

Can you double-check that there is a node_modules folder in the repository's src/VSCodeExtension folder? If not, running npm install should create it.

Also, instead of using vsce package, you could try running the extension in an experimental VS Code instance. The instructions in the "Debugging" section should help: https://github.com/microsoft/qsharp-compiler/blob/main/src/VSCodeExtension/BUILDING.md#debugging

[bamarsha]

The "Cannot find module 'vscode-extension-telemetry'" problem looks like it was caused by a recent update to vsce, but I think that a new update has fixed it - @ashwinpilgaonkar can you try running npm install -g vsce to update vsce and then building the VSIX again?

[ashwinpilgaonkar]

Hi @SamarSha, thanks for all the info!
You can find my replies stated below -

The "Cannot find module 'vscode-extension-telemetry'" problem looks like it was caused by a recent update to vsce, but I think that a new update has fixed it - @ashwinpilgaonkar can you try running npm install -g vsce to update vsce and then building the VSIX again?

I just tried it. The same error still shows up.

It looks like the same error is affecting the latest release of the QDK extension for VS Code, actually, so it seems like it is a separate issue that we will hopefully have a fix for soon. However, for some reason it doesn't affect me when I build the VSIX using vsce package - the extension seems to work when I install it.

Oh, I see.

Can you double-check that there is a node_modules folder in the repository's src/VSCodeExtension folder? If not, running npm install should create it.

You're right, the node_modules folder was indeed missing. I ran npm install, but it doesn't seem to change anything. FYI, regardless of whether the node_modules is present or not, VSCode does detect the installation of the extension (I get the option to uninstall/disable it). But the autocomplete doesn't work and VSCode throws the following error Could not download Q# language server.

When I build a self-contained version of the language server and set the quantumDevKit.languageServerPath path in settings.json, it throws up another error - The Q# Language Server has encountered an error. Diagnostics will be reloaded upon saving the file. Details on the encountered error have been logged to the output window.

[Info  - 5:11:24 pm] workspace folder: c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension
[Error - 5:11:27 pm] Error on loading project 'c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\library\Library.csproj': The SDK 'Microsoft.Quantum.Sdk/0.9999.2010.2010-alpha' specified could not be found.  c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\library\Library.csproj.
Ignoring non-Q# project 'c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\library\Library.csproj'.
[Error - 5:11:28 pm] Error on loading project 'c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\unittest\Test.csproj': The SDK 'Microsoft.Quantum.Sdk/0.9999.2010.2010-alpha' specified could not be found.  c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\unittest\Test.csproj.
Ignoring non-Q# project 'c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\unittest\Test.csproj'.
[Error - 5:11:28 pm] Error on loading project 'c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\application\Application.csproj': The SDK 'Microsoft.Quantum.Sdk/0.9999.2010.2010-alpha' specified could not be found.  c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\application\Application.csproj.
Ignoring non-Q# project 'c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\templates\application\Application.csproj'.
[Error - 5:11:28 pm] Error on loading project 'C:\Users\ashpi\AppData\Local\Temp\qsharp\c_x2f__x2f_Users_x2f_ashpi_x2f_OneDrive_x2f_Documents_x2f_Work_x2f_Open Source_x2f_qsharp-compiler_x2f_src_x2f_VSCodeExtension\generated.csproj': The SDK 'Microsoft.Quantum.Sdk/0.9999.2010.2010-alpha' specified could not be found.  C:\Users\ashpi\AppData\Local\Temp\qsharp\c_x2f__x2f_Users_x2f_ashpi_x2f_OneDrive_x2f_Documents_x2f_Work_x2f_Open Source_x2f_qsharp-compiler_x2f_src_x2f_VSCodeExtension\generated.csproj.
Ignoring non-Q# project 'C:\Users\ashpi\AppData\Local\Temp\qsharp\c_x2f__x2f_Users_x2f_ashpi_x2f_OneDrive_x2f_Documents_x2f_Work_x2f_Open Source_x2f_qsharp-compiler_x2f_src_x2f_VSCodeExtension\generated.csproj'.
[Info  - 5:11:28 pm] Failed to load temporary .csproj for c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\Program.qs.
[Info  - 5:11:29 pm] The file c:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\VSCodeExtension\Program.qs is not associated with a compilation unit. Only syntactic diagnostics are generated.
[Error - 5:11:36 pm] 
=============================
System.ArgumentException: no namespace with the given name exists
   at Microsoft.Quantum.QsCompiler.SymbolManagement.NamespaceManager.TryResolveQualifier(NonNullable`1 qualifier, NonNullable`1 nsName, NonNullable`1 source) in C:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\QsCompiler\Core\SymbolTable.fs:line 805
   at Microsoft.Quantum.QsCompiler.SymbolManagement.NamespaceManager.TryGetCallableHeader(QsQualifiedName callableName, FSharpOption`1 declSource, NonNullable`1 nsName, NonNullable`1 source) in C:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\QsCompiler\Core\SymbolTable.fs:line 1586
   at Microsoft.Quantum.QsCompiler.SymbolManagement.NamespaceManager.TryGetCallable(QsQualifiedName callableName, NonNullable`1 nsName, NonNullable`1 source) in C:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\QsCompiler\Core\SymbolTable.fs:line 1600
   at Microsoft.Quantum.QsCompiler.CompilationBuilder.SuggestedEdits.SuggestionsForIndexRange(FileContentManager file, CompilationUnit compilation, Range range) in C:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\QsCompiler\CompilationManager\EditorSupport\CodeActions.cs:line 396
   at Microsoft.Quantum.QsCompiler.CompilationBuilder.EditorCommands.CodeActions(FileContentManager file, CompilationUnit compilation, Range range, CodeActionContext context) in C:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\QsCompiler\CompilationManager\EditorSupport\EditorCommands.cs:line 146
   at Microsoft.Quantum.QsCompiler.CompilationBuilder.ProjectManager.<>c__DisplayClass25_0.<CodeActions>b__0(FileContentManager file, CompilationUnit c) in C:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\QsCompiler\CompilationManager\ProjectManager.cs:line 1032
   at Microsoft.Quantum.QsCompiler.CompilationBuilder.CompilationUnitManager.<FileQuery>g__TryQueryFile|31_0[T](FileContentManager f, <>c__DisplayClass31_0`1& ) in C:\Users\ashpi\OneDrive\Documents\Work\Open Source\qsharp-compiler\src\QsCompiler\CompilationManager\CompilationUnitManager.cs:line 717
=============================

Also, instead of using vsce package, you could try running the extension in an experimental VS Code instance. The instructions in the "Debugging" section should help: https://github.com/microsoft/qsharp-compiler/blob/main/src/VSCodeExtension/BUILDING.md#debugging

Could you help me out with this?
I went through the docs but I was unable to locate the Debug tab in VSCode.
From the Debug tab in VS Code, ensure that "Extension" is selected in the Debug target menu and press the green ‣.

[bamarsha]

But the autocomplete doesn't work and VSCode throws the following error Could not download Q# language server.

I think this is normal. The extension tries to download a language server with the same version as the extension, but since you built the extension manually, a language server with a matching version number doesn't exist on the download server. So I think setting quantumDevKit.languageServerPath is necessary here.

When I build a self-contained version of the language server and set the quantumDevKit.languageServerPath path in settings.json, it throws up another error - The Q# Language Server has encountered an error. Diagnostics will be reloaded upon saving the file. Details on the encountered error have been logged to the output window.

This is also probably normal, unfortunately - since the language server is asynchronous, sometimes it receives commands that are no longer valid for the current state. These cause exceptions which are ignored in the release build but are shown in debug builds. I think it would be good if the language server handled this more nicely - generally if something is expected to happen often it shouldn't throw an exception, but for now I think it's probably safe to ignore them.

Could you help me out with this?
I went through the docs but I was unable to locate the Debug tab in VSCode.

When you have the VSCodeExtension folder open in VS Code, there should be a button on the right that has a triangle and a bug. If you click that, then click the green triangle at the top, it should run the extension:

[ashwinpilgaonkar]

I think this is normal. The extension tries to download a language server with the same version as the extension, but since you built the extension manually, a language server with a matching version number doesn't exist on the download server. So I think setting quantumDevKit.languageServerPath is necessary here.

Yes.

This is also probably normal, unfortunately - since the language server is asynchronous, sometimes it receives commands that are no longer valid for the current state. These cause exceptions which are ignored in the release build but are shown in debug builds. I think it would be good if the language server handled this more nicely - generally if something is expected to happen often it shouldn't throw an exception, but for now I think it's probably safe to ignore them.

Oh, I see. Okay.

When you have the VSCodeExtension folder open in VS Code, there should be a button on the right that has a triangle and a bug. If you click that, then click the green triangle at the top, it should run the extension:

Thanks, I was able to get the experimental mode running now!

However, there is still a difference in output between the official latest build and the development version, regardless of whether it is installed as a VSIX extension, or being run in debug mode in an experimental instance of VSCode.

Dev build

Official latest build

[bamarsha]

Are you editing a Q# file that is not part of a Q# project? Can you try creating a new Q# project and opening a file inside the project folder? One way to do this is press Ctrl+Shift+P and then type "q# create" in the command palette.

The extra completion items RangeEnd, RangeReverse, etc. come from library functions, which means that a project file needs to exist that has a reference to the library package. If you open a Q# file outside of a project folder, the language server tries to automatically create a project file to use, but the project file it creates has a reference to a package with the same version as the language server itself. Since that version number was created locally and doesn't exist on the package server, the autogenerated project file won't work on non-release versions of the language server. #614 is the issue relating to this.

Also, thanks for your patience through all of these confusing issues. :) I think that I will add these to the README/BUILDING.md files so that getting started with developing the language server is more clear in the future.

[ashwinpilgaonkar]

Are you editing a Q# file that is not part of a Q# project? Can you try creating a new Q# project and opening a file inside the project folder? One way to do this is press Ctrl+Shift+P and then type "q# create" in the command palette.

Yes, all along I was using a sample .qs file that wasn't part of a Q# project. Both the screenshots I provided in my previous reply were obtained after testing on that file.
I did as you said and created a new Q# project. Now the outputs are matching in both cases. That's one problem solved!

The extra completion items RangeEnd, RangeReverse, etc. come from library functions, which means that a project file needs to exist that has a reference to the library package. If you open a Q# file outside of a project folder, the language server tries to automatically create a project file to use, but the project file it creates has a reference to a package with the same version as the language server itself. Since that version number was created locally and doesn't exist on the package server, the autogenerated project file won't work on non-release versions of the language server. #614 is the issue relating to this.

Okay, it makes a lot of sense now.

Also, thanks for your patience through all of these confusing issues. :) I think that I will add these to the README/BUILDING.md files so that getting started with developing the language server is more clear in the future.

It's no problem at all!
In fact its things like these that add to the learning experience. :)