#![feature(unsize)]
#![feature(unsized_locals)]
#![feature(allocator_internals)]
-#![feature(on_unimplemented)]
+#![cfg_attr(bootstrap, feature(on_unimplemented))]
#![feature(rustc_const_unstable)]
#![feature(slice_partition_dedup)]
#![feature(maybe_uninit_extra, maybe_uninit_slice)]