diff --git a/ext/symengine/ruby_basic.c b/ext/symengine/ruby_basic.c
index 1808a55..80cabd3 100644
--- a/ext/symengine/ruby_basic.c
+++ b/ext/symengine/ruby_basic.c
@@ -212,6 +212,7 @@ int insert_entries(VALUE key, VALUE val, VALUE input) {
 
     basic_free_stack(ckey);
     basic_free_stack(cval);
+    return ST_CONTINUE;
 }
 
 VALUE cbasic_subs(int argc, VALUE *argv, VALUE self) {