Dropping the Options API is breaking the application

[cexbrayat]

Version

3.0.0-rc.4

Reproduction link

https://github.com/cexbrayat/vite-playground

Branch: repro/drop-options-api

Steps to reproduce

In a new vite application, add the following configuration vite.config.js:

module.exports = {
  define: {
    __VUE_OPTIONS_API__: false
  }
}

Launch the app: the HelloWorld component is not showing up and the console logs:

[Vue warn]: Failed to resolve component: HelloWorld 
  at <App>

What is expected?

It should not break an application that does not use the Options API.

What is actually happening?

It currently breaks the application in rc.4