--- a/src/ast_dump.rs
+++ b/src/ast_dump.rs
@@ -187,6 +187,12 @@ impl to_string_able for expr {
             expr::Tuple(elts, _) => format!("({})", vec_to_strings_vec(elts).join(", ")),
             expr::Ellipsis => format!("..."),
             expr::Await(value) => format!("await {}", value.to_string()),
+            expr::Yield(value) => {
+                match *value {
+                    None => String::from("yield"),
+                    Some(value) => format!("yield {}", value.to_string())
+                }
+            },
         }
     }
 }