[Bug c++/120961] New: ICE on C++20 module when compiling Eigen.

[shyeyian at petalmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120961

            Bug ID: 120961
           Summary: ICE on C++20 module when compiling Eigen.
           Product: gcc
           Version: 15.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: shyeyian at petalmail dot com
  Target Milestone: ---

I bumped into ICE when compiling Eigen into `C++20 module`. 

The scenary is hard to reduce, but I hope it would provide more information for
maintainers to figure out the bugs in `module` feature.

Everything is in [attachment](gcc-ice-preprocessed.out).

**Thank you!**