diff --git a/include/argparse/argparse.hpp b/include/argparse/argparse.hpp
index a779e01..9226649 100644
--- a/include/argparse/argparse.hpp
+++ b/include/argparse/argparse.hpp
@@ -72,7 +72,7 @@ struct HasContainerTraits<
                    decltype(std::declval<T>().size())>> : std::true_type {};
 
 template <typename T>
-static constexpr bool IsContainer = HasContainerTraits<T>::value;
+inline constexpr bool IsContainer = HasContainerTraits<T>::value;
 
 template <typename T, typename = void>
 struct HasStreamableTraits : std::false_type {};
@@ -84,7 +84,7 @@ struct HasStreamableTraits<
     : std::true_type {};
 
 template <typename T>
-static constexpr bool IsStreamable = HasStreamableTraits<T>::value;
+inline constexpr bool IsStreamable = HasStreamableTraits<T>::value;
 
 constexpr std::size_t repr_max_container_size = 5;