Interestingly one of the reasons launder exist is that without it std::vector is not implementable within the strict letter of the standard. IIRC the issue was

Interestingly one of the reasons launder exist is that without it std::vector is not implementable within the strict letter of the standard. IIRC the issue was that vector construct one object at a time but then access it as if it was part of an array which was never constructed