Error not being thrown for non-async server side arrow functions

[DiskCrasher]

Link to the code that reproduces this issue

https://github.com/DiskCrasher/next-js-issue

To Reproduce

1. Run yarn dev.
2. Browse to http://localhost:3000.
3. Observe "Server actions must be async functions" error for function bar in file ssc.tsx.
4. Delete or comment out bar function.
5. Repeat steps above and observe that similar error is not shown for foo function even though it's not async.

Current vs. Expected behavior

The "Server actions must be async functions" error should appear for both functions.

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 10 Home
  Available memory (MB): 8050
  Available CPU cores: 4
Binaries:
  Node: 20.11.0
  npm: N/A
  Yarn: N/A
  pnpm: N/A
Relevant Packages:
  next: 14.2.0-canary.35 // Latest available version is detected (14.2.0-canary.35).
  eslint-config-next: N/A
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.1.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Middleware / Edge (API routes, runtime)

Which stage(s) are affected? (Select all that apply)

next dev (local), next start (local)

Additional context

No response