diff --git a/include/rapidjson/rapidjson.h b/include/rapidjson/rapidjson.h
index e667d8b..19a3019 100644
--- a/include/rapidjson/rapidjson.h
+++ b/include/rapidjson/rapidjson.h
@@ -413,7 +413,7 @@ RAPIDJSON_NAMESPACE_END
 RAPIDJSON_NAMESPACE_BEGIN
 template <bool x> struct STATIC_ASSERTION_FAILURE;
 template <> struct STATIC_ASSERTION_FAILURE<true> { enum { value = 1 }; };
-template<int x> struct StaticAssertTest {};
+template <size_t x> struct StaticAssertTest {};
 RAPIDJSON_NAMESPACE_END
 
 #define RAPIDJSON_JOIN(X, Y) RAPIDJSON_DO_JOIN(X, Y)