From b0a6ad65d14ec094fabc07f709fd7f87fccb6eed Mon Sep 17 00:00:00 2001
From: Alexander Reinauer <areinauer@icp.uni-stuttgart.de>
Date: Mon, 9 Sep 2024 10:26:59 +0200
Subject: [PATCH] replace decltype by typename for some compilers

---
 src/utils/include/utils/flatten.hpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/utils/include/utils/flatten.hpp b/src/utils/include/utils/flatten.hpp
index 638eaf178da..3f068fd2bd4 100644
--- a/src/utils/include/utils/flatten.hpp
+++ b/src/utils/include/utils/flatten.hpp
@@ -27,8 +27,9 @@ namespace detail {
 template <class Container, class OutputIterator, class = void>
 struct flatten_impl {
   static OutputIterator apply(Container const &c, OutputIterator out) {
+    using ValueType = typename Container::value_type;
     for (auto const &e : c) {
-      out = flatten_impl<decltype(e), OutputIterator>::apply(e, out);
+      out = flatten_impl<ValueType, OutputIterator>::apply(e, out);
     }
 
     return out;