make indice trivially constructible

Author: sloriot

Surface_mesh/include/CGAL/Surface_mesh/Surface_mesh.h

@@ -65,7 +65,10 @@ namespace CGAL {
         /// We write -1, which is <a href="https://en.cppreference.com/w/cpp/types/numeric_limits">
         /// <tt>(std::numeric_limits<size_type>::max)()</tt></a>
         /// as `size_type` is an unsigned type.
-        explicit SM_Index(size_type _idx=(std::numeric_limits<size_type>::max)()) : idx_(_idx) {}
+        constexpr
+        SM_Index() : idx_((std::numeric_limits<size_type>::max)()) {}
+
+        explicit SM_Index(size_type _idx) : idx_(_idx) {}
 
         /// Get the underlying index of this index
         operator size_type() const { return idx_; }
@@ -126,7 +129,7 @@ namespace CGAL {
     {
     public:
 
-        SM_Vertex_index() : SM_Index<SM_Vertex_index>((std::numeric_limits<size_type>::max)()) {}
+        SM_Vertex_index() = default;
 
         explicit SM_Vertex_index(size_type _idx) : SM_Index<SM_Vertex_index>(_idx) {}
 
@@ -171,7 +174,7 @@ namespace CGAL {
         typedef void pointer;
         typedef void reference;
 
-        SM_Halfedge_index() : SM_Index<SM_Halfedge_index>((std::numeric_limits<size_type>::max)()) {}
+        SM_Halfedge_index() = default;
 
         explicit SM_Halfedge_index(size_type _idx) : SM_Index<SM_Halfedge_index>(_idx) {}
 
@@ -206,7 +209,7 @@ namespace CGAL {
     {
     public:
 
-        SM_Face_index() : SM_Index<SM_Face_index>((std::numeric_limits<size_type>::max)()) {}
+        SM_Face_index() = default;
 
         explicit SM_Face_index(size_type _idx) : SM_Index<SM_Face_index>(_idx) {}
 
@@ -241,7 +244,7 @@ namespace CGAL {
     public:
         typedef std::uint32_t size_type;
 
-        SM_Edge_index() : halfedge_((std::numeric_limits<size_type>::max)()) { }
+        SM_Edge_index() = default;
 
         explicit SM_Edge_index(size_type idx) : halfedge_(idx * 2) { }