#![feature(bool_to_option)]
#![feature(box_patterns)]
#![feature(crate_visibility_modifier)]
-#![cfg_attr(bootstrap, feature(format_args_capture))]
#![feature(iter_order_by)]
-#![feature(iter_zip)]
+#![feature(let_else)]
#![feature(never_type)]
#![feature(nll)]
#![feature(control_flow_enum)]