Could not build webpack.config.ts at 5.60.0 with webpack-dev-server.

Bug report

What is the current behavior? At webpack 5.60.0, webpack.config.ts cannot be compiled and builded when property of webpack-dev-server is existed.

If the current behavior is a bug, please provide the steps to reproduce. In my webpack.config.ts, there is a property devServer because I use webpack-dev-server. like:

import webpack from "webpack"
import type { Configuration } from "webpack-dev-server"

const devServer: Configuration = {
  static: {
    directory: path.resolve(__dirname, "/dist"),
  },
  historyApiFallback: true,
  open: true,
  port: 8000,
  hot: true,
  proxy: {
    "/api": "http://localhost:8080",
  },
}

const config: webpack.Configuration = {
  // Omit lines //

  devServer: devServer,
}

When I upgraded webpack from 5.59.1 to 5.60.0, tsc errors on the property that shows:

Object literal may only specify known properties, and 'devServer' does not exist in type 'Configuration'.

What is the expected behavior? At webpack 5.59.1, webpack.config.ts is correctly builded, but at webpack 5.60.0 is not.

Other relevant information: webpack version: 5.60.0 Node.js version: v14.18.1 Operating System: any Additional tools: webpack-dev-server@4.3.1, @types/webpack-dev-server@4.3.1

[alexander-akait]

Don’t worry, all is fine

[KashEight]

I recognized this error was occurred by yarn’s cache when I make reproducible example. So, after I do yarn cache clean, the error was solved. This is all of my fault, sorry for taking time for me…

Edit: error was caused by yarn.lock. Removing and Regenerating it solved this error completely.