message: Explicitly initialize prevector _union
diff: @@ -248,32 +248,32 @@ public:
  prevector() : _size(0), _union{{}} {}
  - explicit prevector(size_type n) : _size(0) {
  + explicit prevector(size_type n) : prevector() {
  resize(n);
  }
  - explicit prevector(size_type n, const T& val) : _size(0) {
  + explicit prevector(size_type n, const T& val) : prevector() {
  change_capacity(n);
  _size += n;
  fill(item_ptr(0), n, val);
  }
  template<typename InputIterator>
  - prevector(InputIterator first, InputIterator last) : _size(0) {
  + prevector(InputIterator first, InputIterator last) : prevector() {
  size_type n = last - first;
  change_capacity(n);
  _size += n;
  fill(item_ptr(0), first, last);
  }
  - prevector(const prevector<N, T, Size, Diff>& other) : _size(0) {
  + prevector(const prevector<N, T, Size, Diff>& other) : prevector() {
  size_type n = other.size();
  change_capacity(n);
  _size += n;
  fill(item_ptr(0), other.begin(), other.end());
  }
  - prevector(prevector<N, T, Size, Diff>&& other) : _size(0) {
  + prevector(prevector<N, T, Size, Diff>&& other) : prevector() {
  swap(other);
  }
  