diff --git a/src/ast/statements/expression.hpp b/src/ast/statements/expression.hpp
index 653c26c..eaec59c 100644
--- a/src/ast/statements/expression.hpp
+++ b/src/ast/statements/expression.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include "ast/ast.hpp"
 #include "token/token.hpp"