ReferenceError: fetchData is not defined

[mjr]

Run next info (available from version 12.0.8 and up)

Operating System:
Platform: darwin
Arch: x64
Version: Darwin Kernel Version 21.2.0: Sun Nov 28 20:28:54 PST 2021; root:xnu-8019.61.5~1/RELEASE_X86_64
Binaries:
Node: 14.18.2
npm: 6.14.15
Yarn: 1.22.17
pnpm: N/A
Relevant packages:
next: 12.0.8-canary.19
react: 17.0.2
react-dom: 17.0.2

What version of Next.js are you using?

12.0.8-canary.19

What version of Node.js are you using?

14.18.2

What browser are you using?

Chrome

What operating system are you using?

macOS

How are you deploying your application?

Vercel

Describe the Bug

After upgrading next to version 12 i get a ReferenceError: fetchData is not defined when using early return without braces inside useEffect, in version 11 it works as expected.

Running the next command in development works as expected, but next build and next start the error happens.

React.useEffect(() => {
  if (query === '') return

  function getFetchUrl() {
    return 'https://hn.algolia.com/api/v1/search?query=' + query
  }

  async function fetchData() {
    const res = await fetch(getFetchUrl())
    const data = await res.json()
    setData(data)
  }

  fetchData()
}, [query])

Expected Behavior

Expected to work without the need to add braces.

To Reproduce

Clone this project https://github.com/mjr/next-bug.
Run next build and then PORT=3000 next start.
Open localhost:3000 e open the console to see the error.

[balazsorban44]

The issue seems to be related to swcMinify: true. I added this to our backlog. In the meantime, swcMinify: false should help you out.

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.