Errors not clear Next 16 Build with Turbopack

[JacobWeisenburger]

after upgrading to next 16, I wanted to start using turbopack. However, it seems that when I run next build then I get a bunch of errors in my terminal but none of it seems to tell me what is wrong or how to fix it. I have tried googling a lot of the terminal outputs with no luck. Can someone please help me understand what I'm doing wrong?

Below I have included the terminal output.

$ next build
   ▲ Next.js 16.0.3 (Turbopack)
   - Environments: .env.local

   Creating an optimized production build ...

> Build error occurred
Error: Turbopack build failed with 5 errors:
./node_modules/@weis-guys/result/index.js
Code generation for chunk item errored
An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-rsc] (ecmascript)

Caused by:
- got 8 segments, expected 4 or 5

Debug info:
- An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-rsc] (ecmascript)
- Execution of <MergedEcmascriptModuleChunkItem as EcmascriptChunkItem>::content_with_async_module_info failed
- Execution of *EcmascriptChunkItemContent::new failed
- Execution of EcmascriptModuleContent::new_merged failed
- got 8 segments, expected 4 or 5

Import traces:
  Server Component:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/serverActions/NewInventoryAlert/server.ts

  App Route:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/LoanApp_server.ts
    ./src/app/api/loan-app/route.ts

  Client Component Browser:
    ./node_modules/@weis-guys/result/index.js [Client Component Browser]
    ./src/constants/schema/Car_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]

  Client Component SSR:
    ./node_modules/@weis-guys/result/index.js [Client Component SSR]
    ./src/constants/schema/Car_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]


./node_modules/@weis-guys/result/index.js
Code generation for chunk item errored
An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-ssr] (ecmascript)

Caused by:
- got 8 segments, expected 4 or 5

Debug info:
- An error occurred while generating the chunk item [project]/node_modules/@weis-guys/result/index.js [app-ssr] (ecmascript)
- Execution of <ModuleChunkItem as EcmascriptChunkItem>::content_with_async_module_info failed
- Execution of *EcmascriptChunkItemContent::new failed
- Execution of EcmascriptModuleContent::new failed
- got 8 segments, expected 4 or 5

Import traces:
  Server Component:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/serverActions/NewInventoryAlert/server.ts

  App Route:
    ./node_modules/@weis-guys/result/index.js
    ./src/lib/LoanApp_server.ts
    ./src/app/api/loan-app/route.ts

  Client Component Browser:
    ./node_modules/@weis-guys/result/index.js [Client Component Browser]
    ./src/constants/schema/Car_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [Client Component Browser]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]

  Client Component SSR:
    ./node_modules/@weis-guys/result/index.js [Client Component SSR]
    ./src/constants/schema/Car_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [Client Component SSR]
    ./src/stores/carsStore_v2.ts [App Route]
    ./src/lib/LoanApp.ts [App Route]
    ./src/lib/LoanApp_server.ts [App Route]
    ./src/app/api/loan-app/route.ts [App Route]

---

This seems to be an unrelated issue, but I still don't know what it's asking me to do.

./node_modules/next/dist/esm/build/templates/app-route.js
Code generation for chunk item errored
An error occurred while generating the chunk item [project]/node_modules/next/dist/esm/build/templates/app-route.js { INNER_APP_ROUTE => "[project]/src/app/api/loan-app/route.ts [app-route] (ecmascript)" } [app-route] (ecmascript)

Caused by:
- got 8 segments, expected 4 or 5

Debug info:
- An error occurred while generating the chunk item [project]/node_modules/next/dist/esm/build/templates/app-route.js { INNER_APP_ROUTE => "[project]/src/app/api/loan-app/route.ts [app-route] (ecmascript)" } [app-route] (ecmascript)
- Execution of <MergedEcmascriptModuleChunkItem as EcmascriptChunkItem>::content_with_async_module_info failed
- Execution of *EcmascriptChunkItemContent::new failed
- Execution of EcmascriptModuleContent::new_merged failed
- got 8 segments, expected 4 or 5

[icyJoseph]

Any chance we could see a repository? Feels like somehow there's some server -> client -> server module imports. I guess Webpack says nothing? Maybe it just silently fails?

[JacobWeisenburger]

I can try to put together a repo on Monday. But my main point is that these errors from turbopack are not helpful.

The only thing I can think of is that the libraries that turbopack has a problem with are libraries that I wrote, so maybe I didn't do something right on them. But they are publicly published thru npm just like any other library.
https://www.npmjs.com/package/@weis-guys/result
https://www.npmjs.com/package/freerstore

When I build my project with webpack, I get no errors.