diff --git a/runtime/to_json_2.cpp b/runtime/to_json_2.cpp
deleted file mode 100644
index a8df02c..0000000
--- a/runtime/to_json_2.cpp
+++ /dev/null
@@ -1,14 +0,0 @@
-#include "json.hpp"
-#include "vm.hpp"
-
-using namespace sliger;
-
-void FlameGraphBuilder::to_json(json::Writer& writer) const
-{
-    writer.add("null");
-}
-
-void CodeCoverageBuilder::to_json(json::Writer& writer) const
-{
-    writer.add("null");
-}