Rollup merge of #58468 - RalfJung:maybe-uninit-split, r=Centril

split MaybeUninit into several features, expand docs a bit

This splits the `maybe_uninit` feature gate into several:

* `maybe_uninit` for what we will hopefully stabilize soon-ish.
* `maybe_uninit_ref` for creating references into `MaybeUninit`, for which the rules are not yet clear.
* `maybe_uninit_slice` for handling slices of `MaybeUninit`, which needs more API design work.
* `maybe_uninit_array` for creating arrays of `MaybeUninit` using a macro (because we don't have https://github.com/rust-lang/rust/issues/49147 yet).

Is that an okay thing to do? The goal is to help people avoid APIs we do not want to stabilize yet. I used this to make sure rustc itself does not use `get_ref` and `get_mut`.

I also extended the docs to advise against uninitialized integers -- again this is something for which the rules are still being discussed.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/liballoc/lib.rs b/src/liballoc/lib.rs
index 95b9dacf856..440ce8ac5e8 100644
--- a/src/liballoc/lib.rs
+++ b/src/liballoc/lib.rs
@@ -112,7 +112,7 @@
 #![feature(rustc_const_unstable)]
 #![feature(const_vec_new)]
 #![feature(slice_partition_dedup)]
-#![feature(maybe_uninit)]
+#![feature(maybe_uninit, maybe_uninit_slice, maybe_uninit_array)]
 #![feature(alloc_layout_extra)]
 #![feature(try_trait)]