// Like cond-triv1.C, but with the declaration order swapped. // { dg-do compile { target concepts } } #include template class optional { struct empty {}; union { empty _ = { }; T value; }; bool engaged = false; public: constexpr optional() = default; constexpr optional(optional const& o) : engaged (o.engaged) { if (engaged) new (&value) T (o.value); } constexpr optional(optional const&) requires std::is_trivially_copy_constructible_v = default; ~optional() { if (engaged) value.~T(); } ~optional() requires std::is_trivially_destructible_v = default; // ... }; struct A { A(); A(const A&); ~A(); }; static_assert(std::is_trivially_copy_constructible_v>); static_assert(!std::is_trivially_copy_constructible_v>); static_assert(std::is_trivially_destructible_v>); static_assert(!std::is_trivially_destructible_v>);