Disable U&& constructor for derived types

boostorg · Mar 12, 2021 · 90cda53 · 90cda53
1 parent f586dc8
commit 90cda53
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/include/boost/variant2/variant.hpp b/include/boost/variant2/variant.hpp
@@ -1581,7 +1581,7 @@ template<class... T> class variant: private detail::variant_ma_base<T...>
 
     template<class U,
         class Ud = typename std::decay<U>::type,
-        class E1 = typename std::enable_if< !std::is_same<Ud, variant>::value && !detail::is_in_place_index<Ud>::value && !detail::is_in_place_type<Ud>::value >::type,
+        class E1 = typename std::enable_if< !std::is_same<Ud, variant>::value && !std::is_base_of<variant, Ud>::value && !detail::is_in_place_index<Ud>::value && !detail::is_in_place_type<Ud>::value >::type,
         class V = detail::resolve_overload_type<U&&, T...>,
         class E2 = typename std::enable_if<std::is_constructible<V, U&&>::value>::type
         >