message: code review: Use std::ptrdiff_t as internal vertex handle type when not yet known
diff: @@ -101,13 +101,17 @@ template<typename D> struct Is_Epeck_D<CGAL::Epeck_d<D>> { static const bool val
  */
  template<class Kernel = CGAL::Epeck_d<CGAL::Dynamic_dimension_tag>, bool Weighted = false>
  class Alpha_complex {
  + private:
  + // Vertex_handle internal type (required by triangulation_ and vertices_).
  + using Internal_vertex_handle = std::ptrdiff_t;
  +
  public:
  /** \brief Geometric traits class that provides the geometric types and predicates needed by the triangulations.*/
  using Geom_traits = std::conditional_t<Weighted, CGAL::Regular_triangulation_traits_adapter<Kernel>, Kernel>;
  // Add an int in TDS to save point index in the structure
  using TDS = CGAL::Triangulation_data_structure<typename Geom_traits::Dimension,
  - CGAL::Triangulation_vertex<Geom_traits, std::ptrdiff_t>,
  + CGAL::Triangulation_vertex<Geom_traits, Internal_vertex_handle>,
  CGAL::Triangulation_full_cell<Geom_traits> >;
  /** \brief A (Weighted or not) Delaunay triangulation of a set of points in \f$ \mathbb{R}^D\f$.*/
  @@ -132,9 +136,6 @@ class Alpha_complex {
  // Vertex_iterator type from CGAL.
  using CGAL_vertex_iterator = typename Triangulation::Vertex_iterator;
  - // size_type type from CGAL.
  - using size_type = typename Triangulation::size_type;
  -
  // Structure to switch from simplex tree vertex handle to CGAL vertex iterator.
  using Vector_vertex_iterator = std::vector< CGAL_vertex_iterator >;
  @@ -149,7 +150,7 @@ class Alpha_complex {
  /** \brief Vertices to be inserted first by the create_complex method to avoid quadratic complexity.
  * It isn't just [0, n) if some points have multiplicity (only one copy appears in the complex).
  */
  - std::vector<std::size_t> vertices_;
  + std::vector<Internal_vertex_handle> vertices_;
  /** \brief Cache for geometric constructions: circumcenter and squared radius of a simplex.*/
  std::vector<Sphere> cache_, old_cache_;
  @@ -261,11 +262,11 @@ class Alpha_complex {
  std::vector<Point_d> point_cloud(first, last);
  // Creates a vector {0, 1, ..., N-1}
  - std::vector<std::ptrdiff_t> indices(boost::counting_iterator<std::ptrdiff_t>(0),
  - boost::counting_iterator<std::ptrdiff_t>(point_cloud.size()));
  + std::vector<Internal_vertex_handle> indices(boost::counting_iterator<Internal_vertex_handle>(0),
  + boost::counting_iterator<Internal_vertex_handle>(point_cloud.size()));
  using Point_property_map = boost::iterator_property_map<typename std::vector<Point_d>::iterator,
  - CGAL::Identity_property_map<std::ptrdiff_t>>;
  + CGAL::Identity_property_map<Internal_vertex_handle>>;
  using Search_traits_d = CGAL::Spatial_sort_traits_adapter_d<Geom_traits, Point_property_map>;
  CGAL::spatial_sort(indices.begin(), indices.end(), Search_traits_d(std::begin(point_cloud)));
  