Tree shaking - a shallow process

[Andarist]

Do you want to request a feature or report a bug?

Bug

What is the current behavior?

If tree-shaken module imports other modules, those other modules stay in the bundle (although not used by anything else). It indicates that tree-shaking is currently a shallow process and doesnt tree-shake unused imports in the unused modules.

If the current behavior is a bug, please provide the steps to reproduce.

https://github.com/Andarist/shallow-tree-shaking-demo

What is the expected behavior?

Tree-shaking of unused imports in unused modules. In the reproduced repository only add module should get included and mult should get tree shaken, because its used only by unused pow.

More detailed information an be found here

If this is a feature request, what is motivation or use case for changing the behavior?

n/a

Please mention other relevant information such as the browser version, Node.js version, webpack version and Operating System.

latest node, latest webpack

[Andarist]

Supposedly this is going to be fixed in webpack 5 - according to this:
https://github.com/webpack/changelog-v5/blob/73dfcf897d687a74cedd74f70c5cb68dbbed5109/README.md#inner-module-tree-shaking