Latest canary causes Webpack to panic

Bug report

Describe the bug

Hi, I wanted to try out Webpack 5. However, when I start the dev server, webpack panics with an error message:

ValidationError: Invalid configuration object. Webpack has been initialized using a configuration object that does not match the API schema.
 - configuration[0].output.environment should be an object:
   object { arrowFunction?, bigIntLiteral?, const?, destructuring?, dynamicImport?, forOf?, module? }
   -> The abilities of the environment where the webpack generated code should run.
 
 ...
 
errors: [
    {
      keyword: 'type',
      dataPath: '[0].output.environment',
      schemaPath: '#/definitions/Environment/type',
      params: [Object],
      message: 'should be object',
      schema: 'object',
      parentSchema: [Object],
      data: 5
    },
    {
      keyword: 'type',
      dataPath: '[1].output.environment',
      schemaPath: '#/definitions/Environment/type',
      params: [Object],
      message: 'should be object',
      schema: 'object',
      parentSchema: [Object],
      data: 5
    }
  ],

To Reproduce

Steps to reproduce the behavior, please provide code snippets or a repository:

1. Create a new project
2. Upgrade next to latest canary
3. Add latest webpack (5.0.0-beta.30) to resolutions
4. See error

Codesandbox:

https://codesandbox.io/s/webpack-5-repro-5vvzs (You may need to restart the server to see the errors)

Expected behavior

For magic to happen.

Screenshots

System information

• OS: macOS, Windows
• Browser (if applies): Chrome, Firefox Developer Edition
• Version of Next.js: ^9.5.4-canary.15
• Version of Node.js: 14.x

Additional context

[ijjk]

Hi, the above PR has been released in v9.5.4-canary.16 of Next.js

[jensmeindertsma]

The fix has now been merged, I suspect a new canary release will be out soon, so you will be able to use the latest Webpack 5 beta 👍