diff --git a/model/sync-std-name-info.h b/model/sync-std-name-info.h
index 34b853a..1821fb4 100644
--- a/model/sync-std-name-info.h
+++ b/model/sync-std-name-info.h
@@ -44,6 +44,9 @@
   virtual bool
   operator == (const NameInfo &info) const;
 
+  virtual bool
+  operator < (const NameInfo &info) const;
+
   virtual std::string
   toString () const;