diff --git a/src/library/user_recursors.cpp b/src/library/user_recursors.cpp
index c9fc22a873..362b10e00b 100644
--- a/src/library/user_recursors.cpp
+++ b/src/library/user_recursors.cpp
@@ -311,6 +311,10 @@ list<name> get_recursors_for(environment const & env, name const & I) {
         return list<name>();
 }
 
+bool is_user_defined_recursor(environment const & env, name const & r) {
+    return recursor_ext::get_state(env).m_recursors.find(r) != nullptr;
+}
+
 has_recursors_pred::has_recursors_pred(environment const & env):
     m_type2recursors(recursor_ext::get_state(env).m_type2recursors) {}
 
diff --git a/src/library/user_recursors.h b/src/library/user_recursors.h
index 6f5fc49f7f..ec6a6f7ceb 100644
--- a/src/library/user_recursors.h
+++ b/src/library/user_recursors.h
@@ -57,6 +57,7 @@ public:
 environment add_user_recursor(environment const & env, name const & r, optional<unsigned> const & major_pos, bool persistent);
 recursor_info get_recursor_info(environment const & env, name const & r);
 list<name> get_recursors_for(environment const & env, name const & I);
+bool is_user_defined_recursor(environment const & env, name const & r);
 
 class has_recursors_pred {
     name_map<list<name>>    m_type2recursors;