#![feature(bool_to_option)]
#![feature(box_syntax)]
#![feature(cell_update)]
-#![cfg_attr(bootstrap, feature(cfg_panic))]
-#![cfg_attr(bootstrap, feature(cfg_target_has_atomic))]
#![feature(const_assume)]
#![feature(const_black_box)]
#![feature(const_bool_to_option)]