diff --git a/include/nlohmann/detail/conversions/to_json.hpp b/include/nlohmann/detail/conversions/to_json.hpp
index ba24c118d..52ddaddef 100644
--- a/include/nlohmann/detail/conversions/to_json.hpp
+++ b/include/nlohmann/detail/conversions/to_json.hpp
@@ -268,8 +268,8 @@ inline void to_json(BasicJsonType& j, T b) noexcept
 }
 
 template<typename BasicJsonType,
-         enable_if_t<std::is_convertible<const std::vector<bool>::reference&, typename BasicJsonType::boolean_t>::value, int> = 0>
-inline void to_json(BasicJsonType& j, const std::vector<bool>::reference& b) noexcept
+         enable_if_t<std::is_convertible<std::vector<bool>::const_reference&, typename BasicJsonType::boolean_t>::value, int> = 0>
+inline void to_json(BasicJsonType& j, std::vector<bool>::const_reference& b) noexcept
 {
     external_constructor<value_t::boolean>::construct(j, static_cast<typename BasicJsonType::boolean_t>(b));
 }