Auto merge of #145916 - matthiaskrgr:rollup-cnvhq2z, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang/rust#142215 (Use -Zmir-opt-level=0 in tests for MIR building)
 - rust-lang/rust#143341 (Mention that casting to *const () is a way to roundtrip with from_raw_parts)
 - rust-lang/rust#145078 (Fix wrong cache line size of riscv64)
 - rust-lang/rust#145290 (Improve std::fs::read_dir docs)
 - rust-lang/rust#145335 (Move WTF-8 code from std into core and alloc)
 - rust-lang/rust#145904 (Move `riscv64-gc-unknown-linux-musl` from Tier 2 with Host tools to Tier 2)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 5 insertions, 3 deletions

diff --git a/library/std/src/sys/os_str/wtf8.rs b/library/std/src/sys/os_str/wtf8.rs
index bbc704ebf86..96da891874e 100644
--- a/library/std/src/sys/os_str/wtf8.rs
+++ b/library/std/src/sys/os_str/wtf8.rs
@@ -1,12 +1,12 @@
 //! The underlying OsString/OsStr implementation on Windows is a
 //! wrapper around the "WTF-8" encoding; see the `wtf8` module for more.
+use alloc::wtf8::{Wtf8, Wtf8Buf};
 use core::clone::CloneToUninit;
 
 use crate::borrow::Cow;
 use crate::collections::TryReserveError;
 use crate::rc::Rc;
 use crate::sync::Arc;
-use crate::sys_common::wtf8::{Wtf8, Wtf8Buf, check_utf8_boundary};
 use crate::sys_common::{AsInner, FromInner, IntoInner};
 use crate::{fmt, mem};
 
@@ -220,7 +220,9 @@ impl Buf {
     /// trailing surrogate half.
     #[inline]
     pub unsafe fn extend_from_slice_unchecked(&mut self, other: &[u8]) {
-        self.inner.extend_from_slice(other);
+        unsafe {
+            self.inner.extend_from_slice_unchecked(other);
+        }
     }
 }
 
@@ -238,7 +240,7 @@ impl Slice {
     #[track_caller]
     #[inline]
     pub fn check_public_boundary(&self, index: usize) {
-        check_utf8_boundary(&self.inner, index);
+        self.inner.check_utf8_boundary(index);
     }
 
     #[inline]