diff --git a/include/algorithm b/include/algorithm
index 2ea1dae..7a6db7a 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -630,7 +630,7 @@
 #include <initializer_list>
 #include <type_traits>
 #include <cstring>
-#include <utility>
+#include <utility> // needed to provide swap_ranges.
 #include <memory>
 #include <iterator>
 #include <cstddef>