[15.0.0-beta.2] vue-loader generates invalid webpack config

[loilo]

Version

15.0.0-beta.2

Reproduction link

https://github.com/Loilo/repro-vue-loader-use-loaders

Steps to reproduce

Clone reproduction repo and install npm dependencies:

git clone https://github.com/Loilo/repro-vue-loader-use-loaders.git
cd repro-vue-loader-use-loaders
npm install

Run webpack:

npx webpack

What is expected?

Webpack should compile as expected.

What is actually happening?

Webpack throws a Rule can only have one result source (provided use and loaders) error.

---

If a loaders option is present inside a rule, vue-loader correctly extracts the its loaders into the use option.

However, it keeps the loaders option, which makes webpack complain about invalid configuration:

Rule can only have one result source (provided use and loaders) in {
  "loaders": [
    "json-loader",
    "yaml-loader"
  ],
  "use": [
    {
      "loader": "json-loader"
    },
    {
      "loader": "yaml-loader"
    },
    {
      "loader": "vue-loader"
    }
  ]
}

The loaders property should probably be removed after attaching the use section.

[yyx990803]

Closed via #1207