From fb403c37c45ee2e7c8fd13887dc5ac7f0b45a7e0 Mon Sep 17 00:00:00 2001
From: Marcel Koch <marcel.koch@kit.edu>
Date: Fri, 30 Jun 2023 09:45:04 +0200
Subject: [PATCH] disable ambiguous range constructor

this should fix the bug reported by sonarcloud: https://sonarcloud.io/project/issues?open=AYTucKfs8qk247btl14g&id=ginkgo-project_ginkgo
---
 include/ginkgo/core/base/range.hpp | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/include/ginkgo/core/base/range.hpp b/include/ginkgo/core/base/range.hpp
index c9713f33572..48789f41f95 100644
--- a/include/ginkgo/core/base/range.hpp
+++ b/include/ginkgo/core/base/range.hpp
@@ -188,6 +188,27 @@ GKO_ATTRIBUTES constexpr GKO_INLINE
            equal_dimensions<CurrentDimension + 1>(first, second);
 }
 
+/**
+ * Helper that stores the first type of a parameter pack, if its length is
+ * greater 0.
+ */
+template <class...>
+struct head;
+
+/**
+ * @copydoc head
+ */
+template <class First, class... Rest>
+struct head<First, Rest...> {
+    using type = First;
+};
+
+/**
+ * @copydoc head
+ */
+template <class... T>
+using head_t = typename head<T...>::type;
+
 
 }  // namespace detail
 
@@ -327,7 +348,11 @@ class range {
      *
      * @param params  parameters forwarded to Accessor constructor.
      */
-    template <typename... AccessorParams>
+    template <typename... AccessorParams,
+              typename = std::enable_if_t<
+                  sizeof...(AccessorParams) != 1 ||
+                  !std::is_same_v<
+                      range, std::decay<detail::head_t<AccessorParams...>>>>>
     GKO_ATTRIBUTES constexpr explicit range(AccessorParams&&... params)
         : accessor_{std::forward<AccessorParams>(params)...}
     {}