ILLEGAL_REASSIGNMENT Error when using defineModel() with reactive()

[wouterkroes]

Describe the bug

I am doing

In this Vue.js example I bind a reactive() to the v-model of a child component (MyComponent.vue). In MyComponent I use defineModel() to implement a two-way binding.

What I expect

When I build the Vue application I would expect no build errors.

What actually happening is

When I build the Vue application vite-rolldown throws the following error:

rolldown-vite v7.1.13 building for production...
✓ 9 modules transformed.
✗ Build failed in 621ms
error during build:
Build failed with 1 error:

[ILLEGAL_REASSIGNMENT] Error: Unexpected re-assignment of const variable `name`
    ╭─[ src/App.vue:16:66 ]
    │
 11 │ const name = reactive({ first: 'john', last: 'doe' });
    │       ──┬─  
    │         ╰─── `name` is declared here as const
    │ 
 16 │     "onUpdate:modelValue": _cache[0] || (_cache[0] = $event => ((name) = $event))
    │                                                                  ──┬─  
    │                                                                    ╰─── `name` is re-assigned here
────╯

    at normalizeErrors (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/rolldown/dist/shared/src-BH2eQDD9.mjs:2175:18)
    at handleOutputErrors (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/rolldown/dist/shared/src-BH2eQDD9.mjs:2910:34)
    at transformToRollupOutput (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/rolldown/dist/shared/src-BH2eQDD9.mjs:2904:2)
    at RolldownBuild.write (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/rolldown/dist/shared/src-BH2eQDD9.mjs:4122:10)
    at async buildEnvironment (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/vite/dist/node/chunks/dep-CqBYPNx_.js:33282:64)
    at async Object.build (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/vite/dist/node/chunks/dep-CqBYPNx_.js:33686:19)
    at async Object.buildApp (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/vite/dist/node/chunks/dep-CqBYPNx_.js:33683:153)
    at async CAC.eval (file:///home/projects/stackblitz-starters-vrpndhpf/node_modules/vite/dist/node/cli.js:656:3)

Extra information

The same Vue app works as expected in the Vue SFC Playground AND on a local npm create vue@latest WITHOUT experimental vite-rolldown.

Reproduction

https://stackblitz.com/edit/stackblitz-starters-vrpndhpf?file=vite.config.js

Steps to reproduce

Run npm run build in the Stackblitz reproduction example.

System Info

The Stackblitz reproduction example was created by running `npm create vue@latest` with experimental vite-rolldown

---


  System:
    OS: Linux 5.0 undefined
    CPU: (4) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 20.19.1 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    @vitejs/plugin-vue: ^6.0.1 => 6.0.1 
    rolldown-vite:  7.1.13

Used Package Manager

npm

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs and the Rolldown-related guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

This is a bug in vue. See vuejs/core#11265

[leechaojie]

I'm also experiencing this issue when migrating to Vite 8.0.0-beta.0.

[DexYang]

same with Vite 8.0.0-beta.1

it is ok in vite 7.2.27, and ok in dev mode in vite 8, only during building in vite 8

[AAAAsea]

same issue here with vite8.0.0