From c64e572716b09c7e537afb728eaa4e0a94aaf2d5 Mon Sep 17 00:00:00 2001
From: Andrey Prokopenko <prokopenkoav@ornl.gov>
Date: Wed, 27 Dec 2023 23:41:53 -0500
Subject: [PATCH] Modernize space filling curve checks

---
 src/ArborX_LinearBVH.hpp                     |  5 ++--
 src/details/ArborX_DetailsBatchedQueries.hpp |  3 +--
 src/details/ArborX_SpaceFillingCurves.hpp    | 26 +++++++-------------
 3 files changed, 12 insertions(+), 22 deletions(-)

diff --git a/src/ArborX_LinearBVH.hpp b/src/ArborX_LinearBVH.hpp
index 6e7e51fe8..6d17e19d3 100644
--- a/src/ArborX_LinearBVH.hpp
+++ b/src/ArborX_LinearBVH.hpp
@@ -307,9 +307,8 @@ BoundingVolumeHierarchy<MemorySpace, Value, IndexableGetter, BoundingVolume>::
   Kokkos::Profiling::pushRegion("ArborX::BVH::BVH::compute_linear_ordering");
 
   // Map indexables from multidimensional domain to one-dimensional interval
-  using LinearOrderingValueType = Kokkos::detected_t<
-      Details::SpaceFillingCurveProjectionArchetypeExpression,
-      SpaceFillingCurve, decltype(bbox), indexable_type>;
+  using LinearOrderingValueType =
+      std::invoke_result_t<SpaceFillingCurve, decltype(bbox), indexable_type>;
   Kokkos::View<LinearOrderingValueType *, MemorySpace> linear_ordering_indices(
       Kokkos::view_alloc(space, Kokkos::WithoutInitializing,
                          "ArborX::BVH::BVH::linear_ordering"),
diff --git a/src/details/ArborX_DetailsBatchedQueries.hpp b/src/details/ArborX_DetailsBatchedQueries.hpp
index 0dc778f45..b06bd848d 100644
--- a/src/details/ArborX_DetailsBatchedQueries.hpp
+++ b/src/details/ArborX_DetailsBatchedQueries.hpp
@@ -57,8 +57,7 @@ struct BatchedQueries
     using Point =
         std::decay_t<decltype(returnCentroid(getGeometry(predicates(0))))>;
     using LinearOrderingValueType =
-        Kokkos::detected_t<SpaceFillingCurveProjectionArchetypeExpression,
-                           SpaceFillingCurve, Box, Point>;
+        std::invoke_result_t<SpaceFillingCurve, Box, Point>;
     Kokkos::View<LinearOrderingValueType *, DeviceType> linear_ordering_indices(
         Kokkos::view_alloc(space, Kokkos::WithoutInitializing,
                            "ArborX::BVH::query::linear_ordering"),
diff --git a/src/details/ArborX_SpaceFillingCurves.hpp b/src/details/ArborX_SpaceFillingCurves.hpp
index dbe19aef5..bc27ded2e 100644
--- a/src/details/ArborX_SpaceFillingCurves.hpp
+++ b/src/details/ArborX_SpaceFillingCurves.hpp
@@ -20,6 +20,8 @@
 #include <Kokkos_DetectionIdiom.hpp>
 #include <Kokkos_Macros.hpp>
 
+#include <type_traits>
+
 namespace ArborX
 {
 namespace Experimental
@@ -74,32 +76,22 @@ struct Morton64
 namespace Details
 {
 
-template <class SpaceFillingCurve, class Box, class Geometry>
-using SpaceFillingCurveProjectionArchetypeExpression =
-    std::invoke_result_t<SpaceFillingCurve, Box, Geometry>;
-
 template <int DIM, class SpaceFillingCurve>
 void check_valid_space_filling_curve(SpaceFillingCurve const &)
 {
   using Point = ExperimentalHyperGeometry::Point<DIM>;
   using Box = ExperimentalHyperGeometry::Box<DIM>;
 
-  static_assert(
-      Kokkos::is_detected<SpaceFillingCurveProjectionArchetypeExpression,
-                          SpaceFillingCurve, Box, Point>::value);
-  static_assert(
-      Kokkos::is_detected<SpaceFillingCurveProjectionArchetypeExpression,
-                          SpaceFillingCurve, Box, Box>::value);
+  static_assert(std::is_invocable_v<SpaceFillingCurve const &, Box, Point>);
+  static_assert(std::is_invocable_v<SpaceFillingCurve const &, Box, Box>);
+
   using OrderValueType =
-      Kokkos::detected_t<SpaceFillingCurveProjectionArchetypeExpression,
-                         SpaceFillingCurve, Box, Point>;
+      std::invoke_result_t<SpaceFillingCurve const &, Box, Point>;
   static_assert(std::is_same<OrderValueType, unsigned int>::value ||
                 std::is_same<OrderValueType, unsigned long long>::value);
-  static_assert(
-      std::is_same<
-          OrderValueType,
-          Kokkos::detected_t<SpaceFillingCurveProjectionArchetypeExpression,
-                             SpaceFillingCurve, Box, Box>>::value);
+  static_assert(std::is_same_v<
+                OrderValueType,
+                std::invoke_result_t<SpaceFillingCurve const &, Box, Box>>);
 }
 
 } // namespace Details