From 71e51b567877d45fe1061e194588d2d840c32a26 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mael=20Rouxel-Labb=C3=A9?=
 <mael.rouxel.labbe@geometryfactory.com>
Date: Mon, 3 Oct 2022 15:08:12 +0200
Subject: [PATCH] Do not use `void` as default for the geom_traits

This change is caused by the improvement of Lookup_named_param_def which added
support for reference named parameters:
https://github.com/CGAL/cgal/commit/aaa3947e4001487e5b2c0c0a14e8459a9c20d7bb
Despite not being required, compilers will try to compile the `::reference`
branch if Eigen is not present, and complain about the type `Default& == void&`

Changing it to `CGAL::Default` will solve that, and align it with what
is done in other packages such as Surface_mesh_parameterization
---
 .../CGAL/Optimal_bounding_box/oriented_bounding_box.h        | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Optimal_bounding_box/include/CGAL/Optimal_bounding_box/oriented_bounding_box.h b/Optimal_bounding_box/include/CGAL/Optimal_bounding_box/oriented_bounding_box.h
index 1433ed2fb9f..acc81a660c3 100644
--- a/Optimal_bounding_box/include/CGAL/Optimal_bounding_box/oriented_bounding_box.h
+++ b/Optimal_bounding_box/include/CGAL/Optimal_bounding_box/oriented_bounding_box.h
@@ -26,6 +26,7 @@
 #include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/convex_hull_3.h>
 #include <CGAL/Convex_hull_traits_3.h>
+#include <CGAL/Default.h>
 #include <CGAL/Iterator_range.h>
 #include <CGAL/Kernel_traits.h>
 #include <CGAL/Random.h>
@@ -338,14 +339,14 @@ void oriented_bounding_box(const PointRange& points,
   typedef typename CGAL::Kernel_traits<Point>::type                                     K;
   typedef Oriented_bounding_box_traits_3<K>                                             Default_traits;
 #else
-  typedef void                                                                          Default_traits;
+  typedef CGAL::Default                                                                 Default_traits;
 #endif
 
   typedef typename internal_np::Lookup_named_param_def<internal_np::geom_traits_t,
                                                        CGAL_BGL_NP_CLASS,
                                                        Default_traits>::type            Geom_traits;
 
-  CGAL_static_assertion_msg(!(std::is_same<Geom_traits, void>::value),
+  CGAL_static_assertion_msg(!(std::is_same<Geom_traits, CGAL::Default>::value),
                             "You must provide a traits class or have Eigen enabled!");
 
   Geom_traits traits = choose_parameter<Geom_traits>(get_parameter(np, internal_np::geom_traits));