TS IntelliSense is very slow or loads endlessly on simple ArkType wrapper

[FunctionDJ]

Type: Performance Issue

• use fresh vanilla / portable VSCode 1.114.0 (no extensions, and i have no custom settings other than TS Server Verbose logging, as shown at the end of the second video)
• clone https://github.com/FunctionDJ/vscode-arktype-issue (includes full tsserver.log from second video!)
• npm install
• see how IntelliSense behaves, e.g. when adding a TS syntax error and using hover (see videos)

I'm aware that this could be an issue with circular types, but then VSCode or tsserver should probably terminate the IntelliSense processing sooner and show an error or something.

Loading IntelliSense status hangs forever when opening the file after launching VSCode:

out1.webm

Adding a syntax error takes extremely long to be recognized and hover never resolves:

out2.webm

VS Code version: Code 1.114.0 (e7fb5e96c0730b9deb70b33781f98e2f35975036, 2026-04-01T09:27:11Z)
OS version: Windows_NT x64 10.0.26200
Modes:

System Info

Item	Value
CPUs	13th Gen Intel(R) Core(TM) i7-13700H (20 x 2918)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x10de, DEVICE=0x25ac [NVIDIA GeForce RTX 3050 6GB Laptop GPU], DRIVER_VENDOR=NVIDIA, DRIVER_VERSION=32.0.15.9597 ACTIVE GPU1: VENDOR= 0x8086, DEVICE=0xa7a0 [Intel(R) Iris(R) Xe Graphics], DRIVER_VERSION=31.0.101.4575 GPU2: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.7309 Machine model name: Machine model version: direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	15.69GB (4.07GB free)
Process Argv	--crash-reporter-id aa49ccd1-a2fe-472e-b2a5-d91f270dd974
Screen Reader	no
VM	0%

Process Info

CPU %	Mem MB	   PID	Process
    0	   137	  1564	code
    0	   196	  2180	extension-host [1]
    0	   103	 16956	     C:\Users\Function\Desktop\vscode-portable\Code.exe c:\Users\Function\Desktop\vscode-portable\e7fb5e96c0\resources\app\extensions\json-language-features\server\dist\node\jsonServerMain --node-ipc --clientProcessId=2180
    0	   235	 22560	     electron-nodejs (tsserver.js)
    0	   115	 16848	       electron-nodejs (typingsInstaller.js)
    0	   173	 23300	     electron-nodejs (tsserver.js)
    0	   123	  4092	pty-host
    0	     8	 16792	     conpty-agent
    0	   103	 24312	     "C:\Program Files\PowerShell\7\pwsh.exe" -noexit -command "try { . \"c:\Users\Function\Desktop\vscode-portable\e7fb5e96c0\resources\app\out\vs\workbench\contrib\terminal\common\scripts\shellIntegration.ps1\" } catch {}"
    1	   381	  5996	window [1] (main.ts - testtemp - Visual Studio Code)
    0	    32	 16836	   crashpad-handler
    0	   153	 21628	shared-process
    0	   112	 21644	file-watcher [1]
    0	   183	 23900	   gpu-process
    0	    47	 24360	   utility-network-service

Workspace Info

|  Window (main.ts - testtemp - Visual Studio Code)
|    Folder (testtemp): 8 files
|      File types: json(3) gitignore(1) ts(1) log(1)
|      Conf files: package.json(1) tsconfig.json(1);

Extensions: none

A/B Experiments

vsliv368cf:30146710
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
6abeh943:31336334
envsactivate1:31464700
cloudbuttont:31379625
aihoversummaries_f:31469309
42190218_ostrepl:31403339
use-responses-api:31390855
ec5jj548:31422691
cp_cls_c_966_ss:31454199
4je02754:31466945
8hhj4413:31478653
cp_cls_c_1081:31454833
core-renderer-profiling-on:31440367
e9c30283:31461165
test_treatment2:31471001
idci7584:31464702
showingstats:31481873
i54ji102:31458073
534a6447:31478749
chat:31457767
t-some:31486549
cpptoolson-v2:31475363
regularsignin:31487065
db0gd219:31481871
ec1eg703:31488002
ddid_c:31478207

[RyanCavanaugh]

🤖 Thank you for your issue! I've done some analysis to help get you started. This response is automatically generated; feel free to 👍 or 👎 this comment according to its usefulness.

Similar Issues

Here are the most similar issues I found

• (73%) microsoft/typescript#46031: Intellisense gets stuck indefinitely in loading
• (73%) microsoft/typescript#30618: tsserver never ends loading intellisense
• (72%) microsoft/typescript#58373: TS hangs up entire computer, type of variables stuck at "Loading..."
• (72%) microsoft/typescript#32826: Very slow intellisense (10-30s until suggestions appear)
• (72%) microsoft/typescript#40138: VSCode incredibly slow, 100% CPU usage, coming from electron_node tsserver.js CPU usage
• (72%) microsoft/typescript#24999: TSServer slow when editing a webpacked file
• (72%) microsoft/typescript#29044: Extremely slow TypeScript server on lowdb types
• (71%) microsoft/typescript#61135: TS Intellisense Performance: Unusable on versions 1.94+
• (71%) microsoft/typescript#45433: Very slow typescript autocomplete/intellisense
• (70%) microsoft/typescript#56155: IntelliSense not functioning in large project sometimes
• (70%) microsoft/typescript#3892: (Master Branch) tsserver.js hangs in vs-code
• (70%) microsoft/typescript#50598: ts-server gets high latency (about 5 seconds per action) for ts/js language feature
• (70%) microsoft/typescript#59283: Intellisense is slow and some things don't work
• (70%) microsoft/typescript#35364: Slow Intellisense with TypeScript
• (70%) microsoft/typescript#22695: Intellisense hangs / stops working

If your issue is a duplicate of one of these, feel free to close this issue. Otherwise, no action is needed.

[RyanCavanaugh]

Something weird is going on here. The video shows you inserting > between 16:57:56 and 16:57:57, but that's exactly when the server log ends. Things are normally responsive for me when I open the provided repo. Maybe @ssalbdivad has clues? Regardless, this doesn't seem likely to mee the 6.0 LS patch bar