https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99642
--- Comment #7 from Marc <gcc.gnu.org.gainfully865 at passmail dot net> --- (In reply to Marc from comment #6) > Same happens with: > > // main.cpp > #include <fstream> > #include <pch.hpp> > > int main() { > } > > // pch.hpp > #pragma once > #include <sstream> Meant to add copmiler args: /usr/bin/g++-13 -I/home/marc/sandbox -g -Wmismatched-tags -Winvalid-pch -include /home/marc/sandbox/build/CMakeFiles/main.dir/cmake_pch.hxx -MD -MT CMakeFiles/main.dir/main.cpp.o -MF CMakeFiles/main.dir/main.cpp.o.d -o CMakeFiles/main.dir/main.cpp.o -c /home/marcd/sandbox/main.cpp -freport-bug