--- a/src/ast_type.rs
+++ b/src/ast_type.rs
@@ -9,6 +9,7 @@ enum Type {
     Bool,
     Int,
     Str,
+    List(Box<Type>),
     Function(Vec<Type>, Vec<Type>),
     Bottom
 }
@@ -236,6 +237,7 @@ impl Visitor<Type> for Typing {
             },
             Expr::Str(_) => Type::Str,
             Expr::Num(_) => Type::Int,
+            Expr::List(_) => Type::List(Box::new(Type::Bottom)),
             Expr::Error => {
                 println!("Expr::Error");
                 panic!()