{"ast_node_type":"other","tokens":[{"end":73,"kind":"keyword","start":0,"text":"debug_assert!(enclosing_breakables.stack.len()"}]}
            debug_assert!(enclosing_breakables.stack.len() == index + 1);
            let mut enclosing_breakables = self.enclosing_breakables.borrow_mut();
            // FIXME(#120456) - is `swap_remove` correct?