diff --git a/src/library/private.cpp b/src/library/private.cpp
index f6db2f0eb..df8efd7df 100644
--- a/src/library/private.cpp
+++ b/src/library/private.cpp
@@ -76,6 +76,10 @@ optional<name> hidden_to_user_name(environment const & env, name const & n) {
     return it ? optional<name>(*it) : optional<name>();
 }
 
+bool is_private(environment const & env, name const & n) {
+    return static_cast<bool>(hidden_to_user_name(env, n));
+}
+
 static int add_private_name(lua_State * L) {
     int nargs = lua_gettop(L);
     optional<unsigned> h;
diff --git a/src/library/private.h b/src/library/private.h
index bcdf6da5b..a2f17de0a 100644
--- a/src/library/private.h
+++ b/src/library/private.h
@@ -31,6 +31,8 @@ pair<environment, name> add_private_name(environment const & env, name const & n
 */
 optional<name> hidden_to_user_name(environment const & env, name const & n);
 
+bool is_private(environment const & env, name const & n);
+
 void open_private(lua_State * L);
 void initialize_private();
 void finalize_private();