diff --git a/include/gsl/pointers b/include/gsl/pointers
index dd0f068..594ef81 100644
--- a/include/gsl/pointers
+++ b/include/gsl/pointers
@@ -117,7 +117,7 @@ public:
     not_null(const not_null& other) = default;
     not_null& operator=(const not_null& other) = default;
     constexpr details::value_or_reference_return_t<T> get() const
-        noexcept(noexcept(details::value_or_reference_return_t<T>{std::declval<T&>()}))
+        noexcept(noexcept(details::value_or_reference_return_t<T>(std::declval<T&>())))
     {
         return ptr_;
     }