Is this behavior of vector::resize(size_type n) under C++11 and Boost.Container correct?

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Not an answer, but a lengthy addendum to Howard’s: I use an allocator adapter that basically works the same as Howard’s allocator, but is safer since

  1. it only interposes on value-initialization and not all initializations,
  2. it correctly default-initializes.
// Allocator adaptor that interposes construct() calls to
// convert value initialization into default initialization.
template <typename T, typename A=std::allocator<T>>
class default_init_allocator : public A {
  typedef std::allocator_traits<A> a_t;
public:
  template <typename U> struct rebind {
    using other =
      default_init_allocator<
        U, typename a_t::template rebind_alloc<U>
      >;
  };

  using A::A;

  template <typename U>
  void construct(U* ptr)
    noexcept(std::is_nothrow_default_constructible<U>::value) {
    ::new(static_cast<void*>(ptr)) U;
  }
  template <typename U, typename...Args>
  void construct(U* ptr, Args&&... args) {
    a_t::construct(static_cast<A&>(*this),
                   ptr, std::forward<Args>(args)...);
  }
};

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