https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117475
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Last reconfirmed| |2024-11-07 Status|UNCONFIRMED |WAITING --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- >It works with clang 17.0.6: It is rejected for me with both libstdc++ and libc++ with clang with -std=c++20: <source>:14:3: error: call to implicitly-deleted default constructor of 'U' 14 | U obj; | ^ <source>:11:5: note: default constructor of 'U' is implicitly deleted because variant field 's' has a non-trivial default constructor 11 | S s; | ^ https://godbolt.org/z/o7fnP8cjM Are you sure you are testing the correct thing with clang?