From ae44cf3ff9a11ec247cac6c8478a6e74a43f0d8b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mael=20Rouxel-Labb=C3=A9?=
 <mael.rouxel.labbe@geometryfactory.com>
Date: Tue, 23 Jul 2019 11:58:21 +0200
Subject: [PATCH] Do not return a const& for Named Parameters' default values

Since 'd' is in general some default constructed value, things can get weird,
for example with default constructed std::function
---
 BGL/include/CGAL/boost/graph/Named_function_parameters.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/BGL/include/CGAL/boost/graph/Named_function_parameters.h b/BGL/include/CGAL/boost/graph/Named_function_parameters.h
index cd1527a68b0..055bfeebc36 100644
--- a/BGL/include/CGAL/boost/graph/Named_function_parameters.h
+++ b/BGL/include/CGAL/boost/graph/Named_function_parameters.h
@@ -204,8 +204,7 @@ get_parameter(const Named_function_parameters<T, Tag, Base>& np, Query_tag tag)
 }
 
 template <typename D>
-const D&
-choose_parameter(const internal_np::Param_not_found&, const D& d)
+D choose_parameter(const internal_np::Param_not_found&, const D& d)
 {
   return d;
 }