Rollup merge of #125082 - kpreid:const-uninit, r=dtolnay

Remove `MaybeUninit::uninit_array()` and replace it with inline const blocks.

\[This PR originally contained the changes in #125995 too. See edit history for the original PR description.]

The documentation of `MaybeUninit::uninit_array()` says:

> Note: in a future Rust version this method may become unnecessary when Rust allows [inline const expressions](https://github.com/rust-lang/rust/issues/76001). The example below could then use `let mut buf = [const { MaybeUninit::<u8>::uninit() }; 32];`.

The PR adding it also said: <https://github.com/rust-lang/rust/pull/65580#issuecomment-544200681>

> if it’s stabilized soon enough maybe it’s not worth having a standard library method that will be replaceable with `let buffer = [MaybeUninit::<T>::uninit(); $N];`

That time has come to pass — inline const expressions are stable — so `MaybeUninit::uninit_array()` is now unnecessary. The only remaining question is whether it is an important enough *convenience* to keep it around.

I believe it is net good to remove this function, on the principle that it is better to compose two orthogonal features (`MaybeUninit` and array construction) than to have a specific function for the specific combination, now that that is possible.

1 files changed, 1 insertions, 1 deletions

diff --git a/library/std/src/sys/pal/windows/mod.rs b/library/std/src/sys/pal/windows/mod.rs
index a1bc2965e2e..6406cec9c27 100644
--- a/library/std/src/sys/pal/windows/mod.rs
+++ b/library/std/src/sys/pal/windows/mod.rs
@@ -225,7 +225,7 @@ where
     // This initial size also works around `GetFullPathNameW` returning
     // incorrect size hints for some short paths:
     // https://github.com/dylni/normpath/issues/5
-    let mut stack_buf: [MaybeUninit<u16>; 512] = MaybeUninit::uninit_array();
+    let mut stack_buf: [MaybeUninit<u16>; 512] = [MaybeUninit::uninit(); 512];
     let mut heap_buf: Vec<MaybeUninit<u16>> = Vec::new();
     unsafe {
         let mut n = stack_buf.len();