https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99426
Mark Millard <markmigm at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |markmigm at gmail dot com --- Comment #5 from Mark Millard <markmigm at gmail dot com> --- I've run into this sort of problem under Fedora 36 with its g++ 12.2.1 : # rm -fr gcm.cache/* # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC ios # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC iostream # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC ostream # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC iomanip In module imported at /usr/include/c++/12/istream:38:1, included from /usr/include/c++/12/sstream:38, from /usr/include/c++/12/bits/quoted_string.h:38, from /usr/include/c++/12/iomanip:45: /usr/include/c++/12/ios: error: failed to read compiled module cluster 927: Bad file data /usr/include/c++/12/ios: note: compiled module file is ‘gcm.cache/./usr/include/c++/12/ios.gcm’ In file included from /usr/include/c++/12/string:53, from /usr/include/c++/12/bits/locale_classes.h:40, from /usr/include/c++/12/bits/ios_base.h:41, from /usr/include/c++/12/iomanip:40: /usr/include/c++/12/bits/basic_string.h:3972:40: fatal error: failed to load pendings for ‘__gnu_cxx::__stoa’ 3972 | { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(), | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 3973 | __idx, __base); } | ~~~~~~~~~~~~~~ compilation terminated. But moving ios to be the last of the 4 did not generate any messages: # rm -fr gcm.cache/* # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC iostream # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC ostream # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC iomanip # c++ -std=c++20 -pedantic -Wall -Wextra -fmodules-ts -g -fPIC ios I've run into other examples of order dependencies. I've not found a way to predict a order that will be tolerated. The "Last reconfirmed" could be updated.