Bug report

What is the current behavior?
Webpack bundled the wrong module with sideEffects enabled. I have two modules A and B, I only used A, but only B in the output bundle.

If the current behavior is a bug, please provide the steps to reproduce.
Here is a minimal reproduction repo: https://github.com/liximomo/webpack-sideEffects-bug

What is the expected behavior?
Webpack bundled the used module.

Other relevant information:
webpack version: 4.41.3
Node.js version: v12.13.0
Operating System: osx