From 59e8aa85b6218da41ad78f0ccd0924a9acd2aa5e Mon Sep 17 00:00:00 2001
From: Jane Tournois <jane.tournois@gmail.com>
Date: Fri, 29 Apr 2022 14:00:58 +0200
Subject: [PATCH] Fix return type of get_parameter_reference (use
 traits::reference, not const auto&)

---
 .../Polygon_mesh_processing/surface_Delaunay_remeshing.h  | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Mesh_3/include/CGAL/Polygon_mesh_processing/surface_Delaunay_remeshing.h b/Mesh_3/include/CGAL/Polygon_mesh_processing/surface_Delaunay_remeshing.h
index 11a8f1fa353..d550f2d3e18 100644
--- a/Mesh_3/include/CGAL/Polygon_mesh_processing/surface_Delaunay_remeshing.h
+++ b/Mesh_3/include/CGAL/Polygon_mesh_processing/surface_Delaunay_remeshing.h
@@ -238,9 +238,15 @@ TriangleMesh surface_Delaunay_remeshing(const TriangleMesh& tmesh
   }
 
   // Sharp features - provided by user as a set of polylines
-  const auto& polylines
+  using Polylines = typename internal_np::Lookup_named_param_def <
+      internal_np::polyline_constraints_t,
+      NamedParameters,
+      std::vector<std::vector<Point_3> > // default
+      >::reference;
+  const Polylines& polylines
     = choose_parameter(get_parameter_reference(np, internal_np::polyline_constraints),
                        std::vector<std::vector<Point_3> >());
+
   if (!polylines.empty() && !protection_of_user_given_constraints)
   {
     std::vector<std::vector<Point_3> > features;