editor.codeActionsOnSave.source.fixAll.ts will result into invalid file

[Sysix]

Type: Bug

VSCode Settings:

{
  "editor.codeActionsOnSave": {
    "source.fixAll.ts": "always" // with never, this bug does not happen
  }
}

Testfile:

const asyncFn = async () => { return Promise.resolve('ok'); };

const abc = (mode: string) => {
  switch (mode) {
    case 'debug':
      await asyncFn();
      break;
    case 'release':
      await asyncFn();
      break;
    default:
      await asyncFn();
  }
}

Saving the File with CTRL + S will result into changes in line 3:

const abc = async async async (mode: string) => {

Expected Result:

const abc = async (mode: string) => {

VS Code version: Code 1.99.3 (17baf84, 2025-04-15T23:18:46.076Z)
OS version: Windows_NT x64 10.0.19045
Modes:
Remote OS version: Linux x64 5.15.167.4-microsoft-standard-WSL2

System Info

Item	Value
CPUs	AMD Ryzen 9 7900X 12-Core Processor (24 x 4700)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on 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 video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	31.10GB (11.35GB free)
Process Argv	--folder-uri=vscode-remote://wsl+Ubuntu/home/sysix/dev/oxc --remote=wsl+Ubuntu --crash-reporter-id 2b3612a4-60c2-4760-b864-459fece876bf
Screen Reader	no
VM	0%

Item	Value
Remote	WSL: Ubuntu
OS	Linux x64 5.15.167.4-microsoft-standard-WSL2
CPUs	AMD Ryzen 9 7900X 12-Core Processor (24 x 0)
Memory (System)	15.18GB (9.33GB free)
VM	0%

Extensions (35)

Extension	Author (truncated)	Version
vscode-jetbrains-keybindings	isu	0.1.9
remote-containers	ms-	0.409.0
remote-wsl	ms-	0.99.0
vscode-icons	vsc	12.12.0
rust-bundle	1Yi	1.0.0
vscode-intelephense-client	bme	1.14.4
vscode-eslint	dba	3.0.10
composer-php-vscode	DEV	1.57.17158
intelli-php-vscode	DEV	0.12.15062
phptools-vscode	DEV	1.57.17158
profiler-php-vscode	DEV	1.57.17158
docker	doc	0.4.10
githistory	don	0.6.20
EditorConfig	Edi	0.17.2
prettier-vscode	esb	11.0.0
dependi	fil	0.7.13
copilot	Git	1.309.0
copilot-chat	Git	0.26.7
vscode-github-actions	git	0.27.1
gti-vscode	Gra	0.6.1
php-cs-fixer	jun	0.3.21
git-graph	mhu	1.30.0
vscode-docker	ms-	1.29.5
extension-test-runner	ms-	0.0.12
live-server	ms-	0.4.15
vscode-yaml	red	1.17.0
rust-analyzer	rus	0.3.2433
vscode-coverage-gutters	rya	2.13.0
markdown-preview-enhanced	shd	0.8.18
code-spell-checker	str	4.0.47
even-better-toml	tam	0.21.2
vscode-lldb	vad	1.11.4
volar	Vue	2.2.10
gitblame	wad	11.1.2
markdown-all-in-one	yzh	3.6.3

A/B Experiments

vsliv368:30146709
vspor879:30202332
vspor708:30202333
vspor363:30204092
pythonvspyt551:31249599
vscod805:30301674
binariesv615:30325510
c4g48928:30535728
azure-dev_surveyone:30548225
962ge761:30959799
h48ei257:31000450
pythontbext0:30879054
cppperfnew:31000557
dwnewjupyter:31046869
pythonrstrctxt:31112756
nativeloc2:31192216
5fd0e150:31155592
dwcopilot:31170013
6074i472:31201624
dwoutputs:31242946
customenabled:31248079
hdaa2157:31222309
copilot_t_ci:31222730
e5gg6876:31282496
cp15370_c:31280196
pythoneinst12:31285622
bgtreat:31268568
4gafe986:31271826
31787653:31262186
3e8i5726:31271747
996jf627:31283433
usemplatestapi:31292913
7bj51361:31289155
747dc170:31275177
g20af354:31278749
aj953862:31281341
generatesymbolt:31295002
convertfstringf:31295003
gendocf:31295004

[albertosantini]

Which extension does use source.fixAll.ts, maybe vscode-eslint?

[Sysix]

Which extension does use source.fixAll.ts, maybe vscode-eslint?

Eslint has source.fixAll.eslint, I expect it has something to do with TS, because the diagnostic I get (before saving) refers to a TS code error.

[albertosantini]

At least, I can reproduce the issue (with only 3 extensions, 2 Copilot and eslint). :)

[albertosantini]

See #185103 forwarding to microsoft/TypeScript#29452