Auto merge of #126319 - workingjubilee:rollup-lendnud, r=workingjubilee

Rollup of 16 pull requests

Successful merges:

 - #123374 (DOC: Add FFI example for slice::from_raw_parts())
 - #124514 (Recommend to never display zero disambiguators when demangling v0 symbols)
 - #125978 (Cleanup: HIR ty lowering: Consolidate the places that do assoc item probing & access checking)
 - #125980 (Nvptx remove direct passmode)
 - #126187 (For E0277 suggest adding `Result` return type for function when using QuestionMark `?` in the body.)
 - #126210 (docs(core): make more const_ptr doctests assert instead of printing)
 - #126249 (Simplify `[T; N]::try_map` signature)
 - #126256 (Add {{target}} substitution to compiletest)
 - #126263 (Make issue-122805.rs big endian compatible)
 - #126281 (set_env: State the conclusion upfront)
 - #126286 (Make `storage-live.rs` robust against rustc internal changes.)
 - #126287 (Update a cranelift patch file for formatting changes.)
 - #126301 (Use `tidy` to sort crate attributes for all compiler crates.)
 - #126305 (Make PathBuf less Ok with adding UTF-16 then `into_string`)
 - #126310 (Migrate run make prefer rlib)
 - #126314 (fix RELEASES: we do not support upcasting to auto traits)

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

library/std/src/env.rs

@@ -323,8 +323,10 @@ impl Error for VarError {
 /// This function is also always safe to call on Windows, in single-threaded
 /// and multi-threaded programs.
 ///
-/// In multi-threaded programs on other operating systems, we strongly suggest
-/// not using `set_var` or `remove_var` at all. The exact requirement is: you
+/// In multi-threaded programs on other operating systems, the only safe option is
+/// to not use `set_var` or `remove_var` at all.
+///
+/// The exact requirement is: you
 /// must ensure that there are no other threads concurrently writing or
 /// *reading*(!) the environment through functions or global variables other
 /// than the ones in this module. The problem is that these operating systems
@@ -390,8 +392,10 @@ unsafe fn _set_var(key: &OsStr, value: &OsStr) {
 /// This function is also always safe to call on Windows, in single-threaded
 /// and multi-threaded programs.
 ///
-/// In multi-threaded programs on other operating systems, we strongly suggest
-/// not using `set_var` or `remove_var` at all. The exact requirement is: you
+/// In multi-threaded programs on other operating systems, the only safe option is
+/// to not use `set_var` or `remove_var` at all.
+///
+/// The exact requirement is: you
 /// must ensure that there are no other threads concurrently writing or
 /// *reading*(!) the environment through functions or global variables other
 /// than the ones in this module. The problem is that these operating systems

library/std/src/sys/pal/windows/rand.rs

@@ -1,6 +1,6 @@
+use core::{mem, ptr};
+
 use crate::sys::c;
-use core::mem;
-use core::ptr;
 
 #[cfg(not(target_vendor = "win7"))]
 #[inline]

library/std/src/sys_common/wtf8.rs

@@ -477,6 +477,9 @@ impl Wtf8Buf {
     /// Part of a hack to make PathBuf::push/pop more efficient.
     #[inline]
     pub(crate) fn as_mut_vec_for_path_buf(&mut self) -> &mut Vec<u8> {
+        // FIXME: this function should not even exist, as it implies violating Wtf8Buf invariants
+        // For now, simply assume that is about to happen.
+        self.is_known_utf8 = false;
         &mut self.bytes
     }
 }

library/std/tests/windows.rs

@@ -0,0 +1,14 @@
+#![cfg(windows)]
+//! An external tests
+
+use std::{ffi::OsString, os::windows::ffi::OsStringExt, path::PathBuf};
+
+#[test]
+#[should_panic]
+fn os_string_must_know_it_isnt_utf8_issue_126291() {
+    let mut utf8 = PathBuf::from(OsString::from("utf8".to_owned()));
+    let non_utf8: OsString =
+        OsStringExt::from_wide(&[0x6e, 0x6f, 0x6e, 0xd800, 0x75, 0x74, 0x66, 0x38]);
+    utf8.set_extension(&non_utf8);
+    utf8.into_os_string().into_string().unwrap();
+}