[Bug c++/103118] [modules] ICE tree check in get_merge_kind at cp/module.cc

[johelegp at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103118

--- Comment #1 from Johel Ernesto Guerrero Peña <johelegp at gmail dot com> ---
To work around this
- Do not include `<chrono>`.
- Explicitly import a module that exports its definitions when you need to use
the chrono library.

I use the headers above to compile a header unit, which I export from a module
to work around the lack of a standard modules. Apparently, `<chrono>` is
indirectly included, as using the chrono library works.