message: Add deduction guide for iterator_range.
diff: @@ -51,14 +51,19 @@ class iterator_range {
  iterator end_;
  };
  +template <typename Iter>
  +iterator_range(Iter, Iter) -> iterator_range<Iter>;
  +
  // Helper function returning an iterator_range using template argument
  // deduction.
  +// OBSOLETE: Use iterator_traits constructor directly.
  template <typename Iter>
  iterator_range<Iter> make_range(Iter begin, Iter end) {
  return iterator_range<Iter>(std::move(begin), std::move(end));
  }
  // Overload to operator on a std::pair of iterators.
  +// OBSOLETE: Use iterator_traits constructor directly.
  template <typename Iter>
  iterator_range<Iter> make_range(std::pair<Iter, Iter> p) {
  return iterator_range<Iter>(std::move(p.first), std::move(p.second));
  