Parcel: Parcel 2: Functions not defined in script tags

[JonathanTroyer]

🐛 bug report

In Parcel 2, calling a function defined in a <script> tag from HTML (i.e. button onclick) leads to a reference error.

🎛 Configuration (.babelrc, package.json, cli command)

{
  "name": "parcel2-inline-script",
  "version": "1.0.0",
  "description": "Shows off a bug with inline scripts in Parcel 2",
  "main": "dist/index.html",
  "scripts": {
    "dev": "parcel src/index.html",
    "build": "parcel src/build index.html"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/JonathanTroyer/Parcel2-inline-script.git"
  },
  "author": "Jonathan Troyer",
  "license": "MIT",
  "bugs": {
    "url": "https://github.com/JonathanTroyer/Parcel2-inline-script/issues"
  },
  "homepage": "https://github.com/JonathanTroyer/Parcel2-inline-script#readme",
  "devDependencies": {
    "parcel": "^2.0.0-alpha.3.2"
  }
}

🤔 Expected Behavior

The function should be run, same as in Parcel

😯 Current Behavior

I get Uncaught Reference Error: x is not defined

💁 Possible Solution

¯\_(ツ)_/¯ It may be related to https://github.com/parcel-bundler/parcel/issues/1618. See also https://github.com/parcel-bundler/parcel/issues/3301

🔦 Context

This is blocking me from transitioning an app from Parcel to Parcel 2, as several pages use script tags on the page.

💻 Code Sample

Demo repo

🌍 Your Environment

| Software | Version(s) |
| ---------------- | ---------- |
| Parcel | 2.0.0-alpha.3.
| Node | 12.13.0
| npm/Yarn | npm 6.12.0
| Operating System | Windows 10 Pro 1909 build 18363.535

[mischnic]

A workaround:

window.test = function ....