https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118582
Bug ID: 118582 Summary: [modules] Bad file data when building <thread> as a header module Product: gcc Version: 15.0 Status: UNCONFIRMED Keywords: rejects-valid Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: nshead at gcc dot gnu.org Blocks: 103524 Target Milestone: --- On current trunk, the following command: g++ -std=c++26 -fmodules -xc++-system-header array format thread Results in the following: In module imported at /.../thread:55:1: /.../format: In function ‘std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, thread::id)’: /.../format: error: failed to read compiled module cluster 1154: Bad file data [-Wtemplate-body] /.../format: note: compiled module file is ‘gcm.cache/./.../format.gcm’ /.../format: error: failed to read compiled module cluster 1914: Bad file data [-Wtemplate-body] /.../format: error: failed to read compiled module cluster 1936: Bad file data [-Wtemplate-body] /.../thread:113:53: fatal error: failed to load pendings for ‘std::__conditional_t’ 113 | thread::native_handle_type>; | ^ compilation terminated. A similar error occurs with the addition of -fno-module-lazy: In module imported at /.../thread:55:1: /.../format: error: failed to read compiled module cluster 1154: Bad file data /.../format: note: compiled module file is ‘gcm.cache/./.../format.gcm’ /.../thread: In destructor ‘std::__codecvt_abstract_base<_InternT, _ExternT, _StateT>::~__codecvt_abstract_base() [with _InternT = char16_t; _ExternT = char; _StateT = __mbstate_t]’: /.../thread:55:76: fatal error: failed to load pendings for ‘std::__codecvt_abstract_base’ 55 | # include <format> | It appears that the module CMI that's been built has been corrupted in some way. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103524 [Bug 103524] [meta-bug] modules issue