diff --git a/include/boost/container/detail/function_detector.hpp b/include/boost/container/detail/function_detector.hpp
index 33134cb..6e43263 100644
--- a/include/boost/container/detail/function_detector.hpp
+++ b/include/boost/container/detail/function_detector.hpp
@@ -80,7 +80,7 @@ namespace function_detector {
       template <class U> \
       static NotFoundType Test( ... ); \
    public : \
-      BOOST_STATIC_CONSTEXPR int check = NotFound + (sizeof(Test<T>(0, 0)) - sizeof(NotFoundType));\
+      BOOST_STATIC_CONSTEXPR int check = NotFound + int(sizeof(Test<T>(0, 0)) - sizeof(NotFoundType));\
    };\
 }}} //namespace boost::container::function_detector {