--- a/src/ast_dump.rs
+++ b/src/ast_dump.rs
@@ -70,6 +70,13 @@ impl Expr {
             Expr::NameConstant(name) => format!("{}", name),
             Expr::Str(s) => format!("\"{}\"", s),
             Expr::Num(n) => format!("{}", n),
+            Expr::List(elts) => format!("[{}]", {
+                let mut elements = vec!();
+                for elt in elts {
+                    elements.push(elt.to_string());
+                }
+                elements.join(", ")
+            }),
             Expr::Error => "Expr::Error".to_string()
         }
     }