TypeScript VS code extension does not work properly for API routes

[jakeleventhal]

Link to the code that reproduces this issue

https://github.com/jakeleventhal/next-types-issue

To Reproduce

Open app/page.tsx and app/api/route.ts and observe no type errors in route.ts in your IDE.

Current vs. Expected behavior

I expected the revalidate export to show a type error in both app/page.tsx and app/api/route.ts, but only the page.tsx shows an error.

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.4.0: Tue Mar  4 21:05:34 PST 2025; root:xnu-11417.100.576.505.3~2/RELEASE_ARM64_T6000
  Available memory (MB): 65536
  Available CPU cores: 10
Binaries:
  Node: 20.18.1
  npm: 10.8.2
  Yarn: 1.22.22
  pnpm: 9.15.9
Relevant Packages:
  next: 15.3.0-canary.10 // Latest available version is detected (15.3.0-canary.10).
  eslint-config-next: N/A
  react: 19.0.0
  react-dom: 19.0.0
  typescript: 5.8.2
Next.js Config:
  output: N/A

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

TypeScript

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

next dev (local)

Additional context

No response