that such dependencies will need private access to each other anyway.

If you want hierarchy (and encapsulation), use dots in the module name like so: 'mylib.class.dep1', 'mylib.class.dep2'. This declares two modules (that will actually be compiled separately). Without exposing private members (with this proposal).

So, TL;DR: Modules could make PIMPL redundant by:

* allowing users to skip importing depended modules if no functions or classes from that module are actually exposed or exported by the parent

* allowing module implementation units to access private members of classes defined within that module

https://redd.it/1tcsv0c
@r_cpp