Auto merge of rust-lang#135525 - jhpratt:rollup-4gu2wpm, r=jhpratt

Rollup of 7 pull requests

Successful merges:

 - rust-lang#132397 (Make missing_abi lint warn-by-default.)
 - rust-lang#133807 (ci: Enable opt-dist for dist-aarch64-linux builds)
 - rust-lang#134143 (Convert `struct FromBytesWithNulError` into enum)
 - rust-lang#134338 (Use a C-safe return type for `__rust_[ui]128_*` overflowing intrinsics)
 - rust-lang#134678 (Update `ReadDir::next` in `std::sys::pal::unix::fs` to use `&raw const (*p).field` instead of `p.byte_offset().cast()`)
 - rust-lang#135424 (Detect unstable lint docs that dont enable their feature)
 - rust-lang#135520 (Make sure we actually use the right trivial lifetime substs when eagerly monomorphizing drop for ADTs)

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

Author: bors

Cargo.lock

@@ -10,7 +10,7 @@ edition = "2021"
 
 [dependencies]
 core = { path = "../core" }
-compiler_builtins = { version = "=0.1.141", features = ['rustc-dep-of-std'] }
+compiler_builtins = { version = "=0.1.143", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
 rand = { version = "0.8.5", default-features = false, features = ["alloc"] }

alloc/Cargo.toml

@@ -124,37 +124,25 @@ pub struct CStr {
 ///
 /// let _: FromBytesWithNulError = CStr::from_bytes_with_nul(b"f\0oo").unwrap_err();
 /// ```
-#[derive(Clone, PartialEq, Eq, Debug)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
 #[stable(feature = "core_c_str", since = "1.64.0")]
-pub struct FromBytesWithNulError {
-    kind: FromBytesWithNulErrorKind,
-}
-
-#[derive(Clone, PartialEq, Eq, Debug)]
-enum FromBytesWithNulErrorKind {
-    InteriorNul(usize),
+pub enum FromBytesWithNulError {
+    /// Data provided contains an interior nul byte at byte `position`.
+    InteriorNul {
+        /// The position of the interior nul byte.
+        position: usize,
+    },
+    /// Data provided is not nul terminated.
     NotNulTerminated,
 }
 
-// FIXME: const stability attributes should not be required here, I think
-impl FromBytesWithNulError {
-    const fn interior_nul(pos: usize) -> FromBytesWithNulError {
-        FromBytesWithNulError { kind: FromBytesWithNulErrorKind::InteriorNul(pos) }
-    }
-    const fn not_nul_terminated() -> FromBytesWithNulError {
-        FromBytesWithNulError { kind: FromBytesWithNulErrorKind::NotNulTerminated }
-    }
-}
-
 #[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")]
 impl Error for FromBytesWithNulError {
     #[allow(deprecated)]
     fn description(&self) -> &str {
-        match self.kind {
-            FromBytesWithNulErrorKind::InteriorNul(..) => {
-                "data provided contains an interior nul byte"
-            }
-            FromBytesWithNulErrorKind::NotNulTerminated => "data provided is not nul terminated",
+        match self {
+            Self::InteriorNul { .. } => "data provided contains an interior nul byte",
+            Self::NotNulTerminated => "data provided is not nul terminated",
         }
     }
 }
@@ -199,8 +187,8 @@ impl fmt::Display for FromBytesWithNulError {
     #[allow(deprecated, deprecated_in_future)]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.write_str(self.description())?;
-        if let FromBytesWithNulErrorKind::InteriorNul(pos) = self.kind {
-            write!(f, " at byte pos {pos}")?;
+        if let Self::InteriorNul { position } = self {
+            write!(f, " at byte pos {position}")?;
         }
         Ok(())
     }
@@ -349,25 +337,25 @@ impl CStr {
     /// use std::ffi::CStr;
     ///
     /// let cstr = CStr::from_bytes_with_nul(b"hello\0");
-    /// assert!(cstr.is_ok());
+    /// assert_eq!(cstr, Ok(c"hello"));
     /// ```
     ///
     /// Creating a `CStr` without a trailing nul terminator is an error:
     ///
     /// ```
-    /// use std::ffi::CStr;
+    /// use std::ffi::{CStr, FromBytesWithNulError};
     ///
     /// let cstr = CStr::from_bytes_with_nul(b"hello");
-    /// assert!(cstr.is_err());
+    /// assert_eq!(cstr, Err(FromBytesWithNulError::NotNulTerminated));
     /// ```
     ///
     /// Creating a `CStr` with an interior nul byte is an error:
     ///
     /// ```
-    /// use std::ffi::CStr;
+    /// use std::ffi::{CStr, FromBytesWithNulError};
     ///
     /// let cstr = CStr::from_bytes_with_nul(b"he\0llo\0");
-    /// assert!(cstr.is_err());
+    /// assert_eq!(cstr, Err(FromBytesWithNulError::InteriorNul { position: 2 }));
     /// ```
     #[stable(feature = "cstr_from_bytes", since = "1.10.0")]
     #[rustc_const_stable(feature = "const_cstr_methods", since = "1.72.0")]
@@ -379,8 +367,8 @@ impl CStr {
                 // of the byte slice.
                 Ok(unsafe { Self::from_bytes_with_nul_unchecked(bytes) })
             }
-            Some(nul_pos) => Err(FromBytesWithNulError::interior_nul(nul_pos)),
-            None => Err(FromBytesWithNulError::not_nul_terminated()),
+            Some(position) => Err(FromBytesWithNulError::InteriorNul { position }),
+            None => Err(FromBytesWithNulError::NotNulTerminated),
         }
     }
 

core/src/ffi/c_str.rs

@@ -17,7 +17,7 @@ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
 panic_unwind = { path = "../panic_unwind", optional = true }
 panic_abort = { path = "../panic_abort" }
 core = { path = "../core", public = true }
-compiler_builtins = { version = "=0.1.141" }
+compiler_builtins = { version = "=0.1.143" }
 unwind = { path = "../unwind" }
 hashbrown = { version = "0.15", default-features = false, features = [
     'rustc-dep-of-std',

std/Cargo.toml

@@ -709,7 +709,7 @@ impl Iterator for ReadDir {
                 // thread safety for readdir() as long an individual DIR* is not accessed
                 // concurrently, which is sufficient for Rust.
                 super::os::set_errno(0);
-                let entry_ptr = readdir64(self.inner.dirp.0);
+                let entry_ptr: *const dirent64 = readdir64(self.inner.dirp.0);
                 if entry_ptr.is_null() {
                     // We either encountered an error, or reached the end. Either way,
                     // the next call to next() should return None.
@@ -735,44 +735,34 @@ impl Iterator for ReadDir {
                 // contents were "simply" partially initialized data.
                 //
                 // Like for uninitialized contents, converting entry_ptr to `&dirent64`
-                // would not be legal. However, unique to dirent64 is that we don't even
-                // get to use `&raw const (*entry_ptr).d_name` because that operation
-                // requires the full extent of *entry_ptr to be in bounds of the same
-                // allocation, which is not necessarily the case here.
-                //
-                // Instead we must access fields individually through their offsets.
-                macro_rules! offset_ptr {
-                    ($entry_ptr:expr, $field:ident) => {{
-                        const OFFSET: isize = mem::offset_of!(dirent64, $field) as isize;
-                        if true {
-                            // Cast to the same type determined by the else branch.
-                            $entry_ptr.byte_offset(OFFSET).cast::<_>()
-                        } else {
-                            #[allow(deref_nullptr)]
-                            {
-                                &raw const (*ptr::null::<dirent64>()).$field
-                            }
-                        }
-                    }};
+                // would not be legal. However, we can use `&raw const (*entry_ptr).d_name`
+                // to refer the fields individually, because that operation is equivalent
+                // to `byte_offset` and thus does not require the full extent of `*entry_ptr`
+                // to be in bounds of the same allocation, only the offset of the field
+                // being referenced.
+                macro_rules! entry_field_ptr {
+                    ($field:ident) => {
+                        &raw const (*entry_ptr).$field
+                    };
                 }
 
                 // d_name is guaranteed to be null-terminated.
-                let name = CStr::from_ptr(offset_ptr!(entry_ptr, d_name).cast());
+                let name = CStr::from_ptr(entry_field_ptr!(d_name).cast());
                 let name_bytes = name.to_bytes();
                 if name_bytes == b"." || name_bytes == b".." {
                     continue;
                 }
 
                 #[cfg(not(target_os = "vita"))]
                 let entry = dirent64_min {
-                    d_ino: *offset_ptr!(entry_ptr, d_ino) as u64,
+                    d_ino: *entry_field_ptr!(d_ino) as u64,
                     #[cfg(not(any(
                         target_os = "solaris",
                         target_os = "illumos",
                         target_os = "aix",
                         target_os = "nto",
                     )))]
-                    d_type: *offset_ptr!(entry_ptr, d_type) as u8,
+                    d_type: *entry_field_ptr!(d_type) as u8,
                 };
 
                 #[cfg(target_os = "vita")]