diff --git a/include/boost/type_traits/intrinsics.hpp b/include/boost/type_traits/intrinsics.hpp
index fff1079..6987750 100644
--- a/include/boost/type_traits/intrinsics.hpp
+++ b/include/boost/type_traits/intrinsics.hpp
@@ -286,7 +286,7 @@
 #   define BOOST_HAS_NOTHROW_CONSTRUCTOR(T) ((__oracle_has_nothrow_constructor(T) || __oracle_has_trivial_constructor(T) || __oracle_is_trivial(T)) && is_default_constructible<T>::value)
 //  __oracle_has_nothrow_copy appears to behave the same as __oracle_has_nothrow_assign, disabled for now:
 //#   define BOOST_HAS_NOTHROW_COPY(T) ((__oracle_has_nothrow_copy(T) || __oracle_has_trivial_copy(T) || __oracle_is_trivial(T)) && !is_volatile<T>::value && !is_reference<T>::value && is_copy_constructible<T>::value)
-#   define BOOST_HAS_NOTHROW_ASSIGN(T) ((__oracle_has_nothrow_assign(T) || __oracle_has_trivial_assign(T) || __oracle_is_trivial(T)) && !is_volatile<T>::value && !is_const<T>::value)
+#   define BOOST_HAS_NOTHROW_ASSIGN(T) ((__oracle_has_nothrow_assign(T) || __oracle_has_trivial_assign(T) || __oracle_is_trivial(T)) && !is_volatile<T>::value && !is_const<T>::value && is_assignable<T&, const T&>::value)
 #   define BOOST_HAS_VIRTUAL_DESTRUCTOR(T) __oracle_has_virtual_destructor(T)
 
 #   define BOOST_IS_ABSTRACT(T) __oracle_is_abstract(T)