diff --git a/generator/tree-gen-cpp.cpp b/generator/tree-gen-cpp.cpp
index e57f669..76e5d16 100644
--- a/generator/tree-gen-cpp.cpp
+++ b/generator/tree-gen-cpp.cpp
@@ -7,6 +7,7 @@
 
 #include <cctype>
 #include <fmt/ostream.h>
+#include <fmt/ranges.h>
 #include <fstream>
 #include <iostream>
 #include <string>