diff --git a/lib/include/cpp-json/json_value.h b/lib/include/cpp-json/json_value.h
index c8fd1ec..5b38567 100644
--- a/lib/include/cpp-json/json_value.h
+++ b/lib/include/cpp-json/json_value.h
@@ -373,11 +373,11 @@ class value {
 	}
 
 	value(const std::nullptr_t &)
-		: storage_(Null()), type_(type_null) {
+		: storage_(Null::Value), type_(type_null) {
 	}
 
 	value()
-		: storage_(Null()), type_(type_null) {
+		: storage_(Null::Value), type_(type_null) {
 	}
 
 public:
@@ -548,7 +548,9 @@ class value {
 	}
 
 private:
-	struct Null {};
+	enum class Null {
+		Value,
+	};
 
 	enum class Boolean {
 		False,