### Version 15.x & 16.x ### Reproduction link [https://github.com/gaodeng/VueLoaderPlugin-Bug](https://github.com/gaodeng/VueLoaderPlugin-Bug) ### Steps to reproduce If Rule.use is a function, the VueLoaderPlugin will cause the Rule.use configuration to be lost and the value to become an empty array. Clone the code repository at https://github.com/gaodeng/VueLoaderPlugin-Bug ``` npm i npm run build ``` Then open the webpack.config.js file and comment out the ``` new VueLoaderPlugin() ``` Run again ``` npm run build ``` Compare the difference in the console output ### What is expected? VueLoaderPlugin should not cause Rule.use configuration to be lost. ### What is actually happening? If Rule.use is a function, the VueLoaderPlugin causes the Rule.use configuration to be lost. --- This problem exists in both 15.x and 16.x versions <!-- generated by vue-issues. DO NOT REMOVE -->