From 940ac3d6e4465cafeda46cb735fc76b783d8cd0c Mon Sep 17 00:00:00 2001
From: Laurent Rineau <laurent.rineau@cgal.org>
Date: Fri, 17 Oct 2025 10:56:40 +0200
Subject: [PATCH] try to please AppleCLang 15

  - ...by adding an explicit deduction guide.
  - and add -fexperimental-library (so that ranges::join is found).
---
 .../test/Constrained_triangulation_3/CMakeLists.txt          | 3 +++
 .../test/Constrained_triangulation_3/cdt_3_from_off.cpp      | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/Constrained_triangulation_3/test/Constrained_triangulation_3/CMakeLists.txt b/Constrained_triangulation_3/test/Constrained_triangulation_3/CMakeLists.txt
index 0c5e6e59ee1..1465facf854 100644
--- a/Constrained_triangulation_3/test/Constrained_triangulation_3/CMakeLists.txt
+++ b/Constrained_triangulation_3/test/Constrained_triangulation_3/CMakeLists.txt
@@ -15,6 +15,9 @@ include(CGAL_setup_tl-excepted)
 add_library(CDT_3_dependencies INTERFACE)
 target_compile_features(CDT_3_dependencies INTERFACE cxx_std_20)
 target_link_libraries(CDT_3_dependencies INTERFACE CGAL::CGAL CGAL::Data CGAL::Eigen3_support tl::expected)
+if(CMAKE_CXX_COMPILER_ID MATCHES "AppleClang")
+  target_compile_options(CDT_3_dependencies INTERFACE -fexperimental-library)
+endif()
 
 create_single_source_cgal_program( "cdt_test_insert_constrained_edge_from_EDG_file.cpp")
 target_link_libraries(cdt_test_insert_constrained_edge_from_EDG_file PRIVATE CDT_3_dependencies)
diff --git a/Constrained_triangulation_3/test/Constrained_triangulation_3/cdt_3_from_off.cpp b/Constrained_triangulation_3/test/Constrained_triangulation_3/cdt_3_from_off.cpp
index 156d1d51aa0..b4c64afa4b1 100644
--- a/Constrained_triangulation_3/test/Constrained_triangulation_3/cdt_3_from_off.cpp
+++ b/Constrained_triangulation_3/test/Constrained_triangulation_3/cdt_3_from_off.cpp
@@ -585,6 +585,11 @@ struct Mesh_property_maps {
   VertexPointMap mesh_vertex_point_map;
 };
 
+// CTAD deduction guide
+template<typename PatchIdMap, typename VertexSelectedMap, typename EdgeBorderMap, typename VertexPointMap>
+Mesh_property_maps(PatchIdMap, VertexSelectedMap, EdgeBorderMap, VertexPointMap)
+        -> Mesh_property_maps<PatchIdMap, VertexSelectedMap, EdgeBorderMap, VertexPointMap>;
+
 auto setup_mesh_property_maps(Mesh& mesh) {
   auto [patch_id_map, patch_id_map_ok] = mesh.add_property_map<face_descriptor, int>("f:patch_id", -2);
   assert(patch_id_map_ok); CGAL_USE(patch_id_map_ok);