Index: src/Common/PersistentMap.h
===================================================================
--- src/Common/PersistentMap.h	(revision fdae91367ec3ec0ae0d11f084e14da4fd527b06c)
+++ src/Common/PersistentMap.h	(revision 42f1279c182e0cf2f329749d809a250ef38193f3)
@@ -122,6 +122,9 @@
 
 public:
-	using size_type = std::size_t;
-
+	using key_type = typename Base::key_type;
+	using mapped_type = typename Base::mapped_type;
+	using value_type = typename Base::value_type;
+	using size_type = typename Base::size_type;
+	using difference_type = typename Base::difference_type;
 	using iterator = typename Base::const_iterator;