https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109448
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|_M_exception_object’ may be |[12/13 Regression] wrong |used uninitialized |uninitialized warning with |[-Werror=maybe-uninitialize |std::variant of an empty |d] |class and | |std::exception_ptr Target Milestone|--- |12.3 Known to fail| |12.1.0 Known to work| |11.3.0 --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Reduced further: ``` #include <variant> #include <cassert> #include <exception> #include <atomic> struct Empty {}; struct Try { Try() = default; ~Try() = default; Try(Empty a): _value(a){} Try(Try&& other) = default; Try& operator=(Try&& other) = default; std::variant<Empty, std::exception_ptr> _value; }; struct TestPromise { void setResult(Try&& value) { if(_state != 0) __builtin_abort(); _try_value = std::move(value); } std::atomic<int> _state = 0; Try _try_value; }; int main() { TestPromise promise; promise.setResult(Empty()); } ```