https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118582
Nathaniel Shead <nshead at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |ASSIGNED Ever confirmed|0 |1 Last reconfirmed| |2025-01-21 Assignee|unassigned at gcc dot gnu.org |nshead at gcc dot gnu.org --- Comment #1 from Nathaniel Shead <nshead at gcc dot gnu.org> --- Reduced: // a.hpp template <typename> struct I; template <typename T> requires (!requires { T::x; }) struct I<T> { using type = int; }; template <typename> struct R { friend void f(); }; // b.hpp import "a.hpp"; using T = I<R<int>>::type; // c.hpp import "b.hpp"; g++ -std=c++26 -fmodules -fno-module-lazy [abc].hpp: In module imported at c.hpp:1:1: ./b.hpp: error: failed to read compiled module cluster 1: Bad file data ./b.hpp: note: compiled module file is ‘gcm.cache/,/b.hpp.gcm’ ./b.hpp: error: failed to read compiled module: Bad file data ./b.hpp: fatal error: returning to the gate for a mechanical issue compilation terminated.