diff --git a/include/boost/container/detail/std_fwd.hpp b/include/boost/container/detail/std_fwd.hpp
index 1277df0..6f64af1 100644
--- a/include/boost/container/detail/std_fwd.hpp
+++ b/include/boost/container/detail/std_fwd.hpp
@@ -66,6 +66,8 @@ class insert_iterator;
 
 struct allocator_arg_t;
 
+struct piecewise_construct_t;
+
 BOOST_CONTAINER_STD_NS_END
 
 #ifdef BOOST_CONTAINER_CLANG_INLINE_STD_NS