diff --git a/src/lib/iter-tree-explorer.hpp b/src/lib/iter-tree-explorer.hpp
index c3af24eea..0493b9792 100644
--- a/src/lib/iter-tree-explorer.hpp
+++ b/src/lib/iter-tree-explorer.hpp
@@ -354,7 +354,7 @@ namespace lib {
         template<class IT>
         struct ArgAccessor<IT,   enable_if<std::is_convertible<typename IT::value_type, Arg>>>
           {
-            static auto build() { return [](auto iter) { return *iter; }; }
+            static auto build() { return [](auto& iter) { return *iter; }; }
           };