diff --git a/src/corelib/global/qflags.h b/src/corelib/global/qflags.h
index e048e73a369..c3174085537 100644
--- a/src/corelib/global/qflags.h
+++ b/src/corelib/global/qflags.h
@@ -172,6 +172,8 @@ private:
         return (it == end ? Int(0) : (Int(*it) | initializer_list_helper(it + 1, end)));
     }
 
+    template <typename E> friend QDataStream &operator<<(QDataStream &, QFlags<E>);
+    template <typename E> friend QDataStream &operator>>(QDataStream &, QFlags<E> &);
     Int i;
 };
 
diff --git a/src/corelib/serialization/qdatastream.h b/src/corelib/serialization/qdatastream.h
index 32b0f96ab89..2a5622f6030 100644
--- a/src/corelib/serialization/qdatastream.h
+++ b/src/corelib/serialization/qdatastream.h
@@ -516,16 +516,11 @@ inline QDataStream &QDataStream::operator<<(quint64 i)
 
 template <typename Enum>
 inline QDataStream &operator<<(QDataStream &s, QFlags<Enum> e)
-{ return s << typename QFlags<Enum>::Int(e); }
+{ return s << e.i; }
 
 template <typename Enum>
 inline QDataStream &operator>>(QDataStream &s, QFlags<Enum> &e)
-{
-    typename QFlags<Enum>::Int i;
-    s >> i;
-    e = QFlag(i);
-    return s;
-}
+{ return s >> e.i; }
 
 template <typename T>
 typename std::enable_if_t<std::is_enum<T>::value, QDataStream &>