add compile index in range check for __type_pack_element branch.

mapbox · Oct 20, 2017 · 8b1de31 · 8b1de31
1 parent ae19314
commit 8b1de31
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/include/mapbox/variant.hpp b/include/mapbox/variant.hpp
@@ -1033,6 +1033,7 @@ struct variant_alternative;
 template <std::size_t Index, typename ...Types>
 struct variant_alternative<Index, variant<Types...>>
 {
+    static_assert(sizeof...(Types) > Index , "Index out of range");
     using type = __type_pack_element<Index, Types...>;
 };
 #endif