struct A {
  int x, y, z;
};

void ?{}(A * a, int x) {
  (&a->x){ x+999 };
  a->y = 0; // not technically a constructor, but okay
} // z never constructed

struct B {
  A a1, a2, a3;
};

void ?{}(B * b) {
  b->a2 = (A) { 2 }; // a2 used before constructed
  (&b->a1){ 1 };
} // a2, a3 never constructed

void ^?{}(B * b) {
  b->a2 = (A) { 0 };
  ^(&b->a1){};
} // a2, a3 never destructed

int main() {
  B b;
}