`script setup` sometimes generate invalid code when using `defineEmit` and `defineProps`

[leopiccionia]

Version

3.0.4

Reproduction link

https://github.com/leopiccionia/vue-script-setup-emit-repro

Steps to reproduce

Just run the repro, with npm run dev.

What is expected?

Compiler should generate valid code.

What is actually happening?

Code fails with syntax error.

The problem is in this line from output:

import { , ref } from '/@modules/vue.js'

The preceding comma is not valid in this place of import statement.

A workaround is changing the order of imports, so that defineEmit and defineProps are trailing.

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I'm not sure if this is a Vite-specific error. I can move the issue, if needed.

[leopiccionia]

I think that PR #2729 should be a fix.

[HcySunYang]

I did not notice that #3088 is a duplicate of this issue, and I submitted a fix there. So I also linked my PR here, because there are some differences between my PR and #2729