[leni536]

> This is the only UB here.

That's debateable.

1. new[] doesn't return a pointer that is suitable for storage for the objects. Yes the objects are empty (only contain padding), but that doesn't absolve from UB.

2. "" is used at two places, assuming that they refer to the same const char array. This is optimization is allowed, commonly implemented, but not guaranteed.

3. An empty struct having 1 byte size is also implementation defined, although common ABIs specify this. It also wouldn't make sense to implement it differently.