Editor Semantic Highlighting stopped working (Windows 10)

[richbobo]

Issue Type: Bug

At some point today, Semantic Highlighting stopped working on my Windows 10 machine. I have tried disabling all extensions, switching themes, logout/login, checked for extension updates, relaunched VS Code and nothing helps.

I also use VS Code on a macOS system and that is still working fine.

Both my Windows 10 machine and my macOS machine have the latest VS Code release - 1.56.1. They also sync settings between systems.

VS Code version: Code 1.56.1 (e713fe9, 2021-05-06T10:08:05.141Z)
OS version: Windows_NT x64 10.0.18362

System Info

Item	Value
CPUs	Intel(R) Xeon(R) CPU E5-2697A v4 @ 2.60GHz (64 x 2594)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	63.92GB (43.49GB free)
Process Argv	--crash-reporter-id ac5fa1a5-26a7-418c-93a8-0122a4cf66c2
Screen Reader	no
VM	0%

Extensions (26)

Extension	Author (truncated)	Version
numbered-bookmarks	ale	8.0.3
vscode-custom-css	be5	5.0.3
vscode-to-photoshop	bia	0.0.3
better-toml	bun	0.3.2
vscode-eslint	dba	2.1.20
githistory	don	0.6.16
xml	Dot	2.5.1
gitlens	eam	11.4.1
vscode-html-css	ecm	1.10.2
python-ultisnippets	eli	2.7.0
pythonsnippets	frh	1.0.2
vscode-pull-request-github	Git	0.26.0
vsc-python-indent	Kev	1.14.2
git-graph	mhu	1.30.0
gitignore	mic	1.0.1
python	ms-	2021.5.829140558
vscode-pylance	ms-	2021.5.1
jupyter	ms-	2021.6.832593372
vscode-gitignore-generator	pio	1.0.3
vscode-yaml	red	0.18.0
mel	sat	0.1.2
vscode-smoothtype	spi	1.2.0
open-in-browser	tec	2.0.0
rst-vscode	tht	3.0.1
vscode-todo-highlight	way	1.0.4
pyqt-integration	zho	0.2.0

(1 theme extensions excluded)

A/B Experiments

vsliv368cf:30146710
vsreu685:30147344
python383cf:30185419
pythonvspyt602:30300191
vspor879:30202332
vspor708:30202333
vspor363:30204092
pythonvspyt639:30300192
pythontb:30283811
pythonvspyt551cf:30291415
vspre833:30267464
pythonptprofiler:30281270
vshan820:30294714
pythondataviewer:30285071
vscus158cf:30286554
bridgeflight:30299254

[aeschli]

With what language? TypeScript?

[richbobo]

Sorry - I'm using Python.

Also, I've tried other themes, just to see if it was something that only affected the one I was using.

To check, I open the Settings window, search for "semantic", then switch the Editor > Semantic Highlighting setting from true to false to true to configuredByTheme - and nothing changes in my Python code.

[richbobo]

Just now updated to VS Code 1.56.2 and that did not change anything - still no semantic highlighting in Windows 10.

[aeschli]

Can you check whether you get semantic highlighting in TypeScript:

for (const arg of process.argv) {
	console.log(arg)
}

Use the Developer: Inspect Editor tokens and scope command over arg and you should see a section semantic topen type.
Try it with the default theme.

[richbobo]

I can confirm that semantic highlighting is working with TypeScript. I tried a few different themes and all seem to toggle fine.

[richbobo]

(I had to go find some TypeScript samples to use - I primarily code in Python! ;^) )

[aeschli]

Ok, then I suspect this is related to the Python extension. Can you file an issue there?
https://github.com/Microsoft/vscode-python/issues

[richbobo]

SOLUTION:

I know this issue has been closed, but I thought it might be helpful to others to know what the solution was.

I discovered through some trial and error that my Windows mapped drive was the problem. Quitting VS Code, disconnecting the mapped drive and remaking it fixed the problem!

I have no idea what the root cause was, but maybe someone else can speculate...