Trying to create gtkmm 4 header unit using g++ 15 with:
g++ -std=c++23 -fmodules -fsearch-include-path -fmodule-header gtkmm.h `pkg-config --cflags gtkmm-4.0`
I get the following error:
/usr/include/gtkmm-4.0/gtkmm.h: internal compiler error: in core_vals, at cp/module.cc:6641
0x1f3713b internal_error(char const*, ...)
../../gcc-15.1.0/gcc/diagnostic-global-context.cc:517
Have I done something incorrectly or is there a workaround for this possible compiler bug?
Good news.
Now with g++ released today (aug 8, 2025) version 15.2, gtkmm 4.0 header unit compile without errors!