https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115190
--- Comment #8 from Peter Damianov <peter0x44 at disroot dot org> --- I have been totally unable to reproduce this outside of MSYS2, with any compilers I built myself. The "MSYS2 MSYS" shell also doesn't have this problem. I can't explain why. I tried investigating, but didn't have success. Peter@DESKTOP-1SHN9FA UCRT64 ~ $ g++ -std=c++20 -fmodules-ts -fmodule-mapper=a.modmap -E -o /dev/null -x c++ /dev/null nul: error: failed reading mapper 'a.modmap' Peter@DESKTOP-1SHN9FA UCRT64 ~ $ /c/Users/Peter/3D\ Objects/mydevkit/bin/g++ -B /c/Users/Peter/3D\ Objects/mydevkit/bin/ -std=c++20 -fmodules-ts -fmodule-mapper=a.modmap -E -o /dev/null -x c++ /dev/null Peter@DESKTOP-1SHN9FA UCRT64 ~ $ g++ -B /c/Users/Peter/3D\ Objects/mydevkit/bin/ -std=c++20 -fmodules-ts -fmodule-mapper=a.modmap -E -o /dev/null -x c++ /dev/null nul: error: failed reading mapper 'a.modmap'
