diff --git a/src/parser.c b/src/parser.c
index ac5f8c8..28271c1 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -1071,7 +1071,6 @@ libab_result _parse_expression(struct parser_state* state,
         result = LIBAB_UNEXPECTED;
     }
 
-    ll_foreach(&op_stack, NULL, compare_always, _parser_foreach_free_tree);
     ll_foreach(&out_stack, NULL, compare_always, _parser_foreach_free_tree);
     ll_free(&op_stack);
     ll_free(&out_stack);