https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83000
Bug ID: 83000 Summary: Constraints for union-templates do not work Product: gcc Version: 8.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: wilhelm.me...@hs-kl.de Target Milestone: --- In the following example, the requirement is not met. But the template-union Test is instantiated: template<typename T> requires (sizeof(T) > 1) union Test { }; int main(){ Test<char> x; } If one changes the union into a struct, the requirement is correctly checked and the struct-template not instantiated.