#![feature(intra_doc_pointers)]
#![feature(lang_items)]
#![feature(let_chains)]
+#![feature(let_else)]
#![feature(linkage)]
#![feature(min_specialization)]
#![feature(must_not_suspend)]
#![feature(map_try_insert)]
#![feature(new_uninit)]
#![feature(thin_box)]
-#![feature(toowned_clone_into)]
#![feature(try_reserve_kind)]
#![feature(vec_into_raw_parts)]
+#![feature(slice_concat_trait)]
//
// Library features (unwind):
#![feature(panic_unwind)]
// to import the prelude implicitly when building crates that depend on std.
#[prelude_import]
#[allow(unused)]
-use prelude::v1::*;
+use prelude::rust_2021::*;
// Access to Bencher, etc.
#[cfg(test)]