From 74d86a169a9a2390fedb9a645f5e0afaaa0f4f4a Mon Sep 17 00:00:00 2001
From: Stephen Nicholas Swatman <stephen.nicholas.swatman@cern.ch>
Date: Fri, 31 May 2024 10:26:38 +0200
Subject: [PATCH] Fix C++20 bug in axis constructor

For reasons that I cannot fully explain, the default `multi_bin`
constructor introduces a compiler error in C++20. This commit removes
that constructor which seems to repair the situation.
---
 core/include/detray/utils/grid/detail/axis.hpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/core/include/detray/utils/grid/detail/axis.hpp b/core/include/detray/utils/grid/detail/axis.hpp
index 4f890b4b1e..e11dd1e307 100644
--- a/core/include/detray/utils/grid/detail/axis.hpp
+++ b/core/include/detray/utils/grid/detail/axis.hpp
@@ -31,9 +31,7 @@ namespace detray::axis {
 
 /// @brief Multi-bin: contains bin indices from multiple axes
 template <std::size_t DIM, typename index_t = dindex>
-struct multi_bin : public dmulti_index<index_t, DIM> {
-    constexpr multi_bin() = default;
-};
+struct multi_bin : public dmulti_index<index_t, DIM> {};
 
 /// @brief Helper to tie two bin indices to a range.
 /// @note Cannot use dindex_range for signed integer bin indices.