Link to the code that reproduces this issue

https://github.com/bennajah/nextjs-app-16-canary-12

To Reproduce

1. create next app (npx create-next-app@canary)
2. start dev server (npm run dev)
3. check tsconfig.json file and console warning

Current vs. Expected behavior

Warning appears in console when running next dev

We detected TypeScript in your project and reconfigured your tsconfig.json file for you.
The following suggested values were added to your tsconfig.json. These values can be changed to fit your project's needs:

        - include was updated to add '.next\dev/types/**/*.ts'
        - include was updated to add '.next\dev/types/**/*.ts'

Duplicate lines added to tsconfig.json

{
  ...
  "include": [
    "next-env.d.ts",
    "**/*.ts",
    "**/*.tsx",
    ".next/types/**/*.ts",
    ".next/dev/types/**/*.ts",
    "**/*.mts",
    ".next\\dev/types/**/*.ts",
    ".next\\dev/types/**/*.ts"
  ],
  ...
}

Provide environment information

Operating System:
  Platform: win32
  Arch: x64
  Version: Windows 11 Pro
  Available memory (MB): 12244
  Available CPU cores: 8
Binaries:
  Node: 22.20.0
  npm: 11.6.2
  Yarn: 1.22.22
  pnpm: 10.18.2
Relevant Packages:
  next: 16.0.0-canary.12 // Latest available version is detected (16.0.0-canary.12).
  eslint-config-next: N/A
  react: 19.2.0
  react-dom: 19.2.0
  typescript: 5.9.3
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