diff --git a/src/compiler/CodeGen.cpp b/src/compiler/CodeGen.cpp
index 35db285..37e1467 100644
--- a/src/compiler/CodeGen.cpp
+++ b/src/compiler/CodeGen.cpp
@@ -1,5 +1,6 @@
 #include <iostream>
 #include <libgen.h>
+#include <functional>
 #include <limits.h>
 #include <unistd.h>
 #include <iterator>