Miscellaneous fixes for the rustc-dep-of-std build. (#820)

- Fix `-D elided-lifetimes-in-paths` diagnostics
 - Fix incorrect target_arch name "power"
 - Add a `try_clone_to_owned` function to the no_std polyfill's `BorrowedFd`.

.github/workflows/main.yml

@@ -39,7 +39,7 @@ jobs:
 
     env:
       # -D warnings is commented out in our install-rust action; re-add it here.
-      RUSTFLAGS: -D warnings --cfg criterion
+      RUSTFLAGS: -D warnings -D elided-lifetimes-in-paths --cfg criterion
     steps:
     - uses: actions/checkout@v3
       with:
@@ -131,7 +131,7 @@ jobs:
 
     env:
       # -D warnings is commented out in our install-rust action; re-add it here.
-      RUSTFLAGS: -D warnings
+      RUSTFLAGS: -D warnings -D elided-lifetimes-in-paths
     steps:
     - uses: actions/checkout@v3
       with:
@@ -538,7 +538,7 @@ jobs:
             qemu_target: arm-linux-user
     env:
       # -D warnings is commented out in our install-rust action; re-add it here.
-      RUSTFLAGS: -D warnings
+      RUSTFLAGS: -D warnings -D elided-lifetimes-in-paths
       QEMU_BUILD_VERSION: 8.0.2
     steps:
     - uses: actions/checkout@v3
@@ -625,7 +625,7 @@ jobs:
             qemu_target: ppc64le-linux-user
     env:
       # -D warnings is commented out in our install-rust action; re-add it here.
-      RUSTFLAGS: --cfg rustix_use_experimental_asm -D warnings
+      RUSTFLAGS: --cfg rustix_use_experimental_asm -D warnings -D elided-lifetimes-in-paths
       RUSTDOCFLAGS: --cfg rustix_use_experimental_asm
       CARGO_TARGET_POWERPC64LE_UNKNOWN_LINUX_GNU_RUSTFLAGS: --cfg rustix_use_experimental_asm
       QEMU_BUILD_VERSION: 8.0.2

Cargo.toml

@@ -235,6 +235,7 @@ rustc-dep-of-std = [
     "dep:compiler_builtins",
     "linux-raw-sys/rustc-dep-of-std",
     "bitflags/rustc-dep-of-std",
+    "compiler_builtins?/rustc-dep-of-std",
 ]
 
 # Obsolete and deprecated.

build.rs

@@ -34,6 +34,9 @@ fn main() {
     // enable the libc backend even if rustix is depended on transitively.
     let cfg_use_libc = var("CARGO_CFG_RUSTIX_USE_LIBC").is_ok();
 
+    // Check for `--features=rustc-dep-of-std`.
+    let rustc_dep_of_std = var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
+
     // Check for eg. `RUSTFLAGS=--cfg=rustix_use_experimental_features`. This
     // is a rustc flag rather than a cargo feature flag because it's
     // experimental and not something we want accidentally enabled via
@@ -52,7 +55,10 @@ fn main() {
 
     // If experimental features are enabled, auto-detect and use available
     // features.
-    if rustix_use_experimental_features {
+    if rustc_dep_of_std {
+        use_feature("rustc_attrs");
+        use_feature("core_intrinsics");
+    } else if rustix_use_experimental_features {
         use_feature_or_nothing("rustc_attrs");
         use_feature_or_nothing("core_intrinsics");
     }

src/backend/libc/fs/syscalls.rs

@@ -2040,12 +2040,12 @@ pub(crate) fn fcntl_fullfsync(fd: BorrowedFd<'_>) -> io::Result<()> {
 }
 
 #[cfg(apple)]
-pub(crate) fn fcntl_nocache(fd: BorrowedFd, value: bool) -> io::Result<()> {
+pub(crate) fn fcntl_nocache(fd: BorrowedFd<'_>, value: bool) -> io::Result<()> {
     unsafe { ret(c::fcntl(borrowed_fd(fd), c::F_NOCACHE, value as c::c_int)) }
 }
 
 #[cfg(apple)]
-pub(crate) fn fcntl_global_nocache(fd: BorrowedFd, value: bool) -> io::Result<()> {
+pub(crate) fn fcntl_global_nocache(fd: BorrowedFd<'_>, value: bool) -> io::Result<()> {
     unsafe {
         ret(c::fcntl(
             borrowed_fd(fd),

src/backend/libc/io/syscalls.rs

@@ -79,7 +79,7 @@ pub(crate) fn pwrite(fd: BorrowedFd<'_>, buf: &[u8], offset: u64) -> io::Result<
 }
 
 #[cfg(not(target_os = "espidf"))]
-pub(crate) fn readv(fd: BorrowedFd<'_>, bufs: &mut [IoSliceMut]) -> io::Result<usize> {
+pub(crate) fn readv(fd: BorrowedFd<'_>, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
     unsafe {
         ret_usize(c::readv(
             borrowed_fd(fd),
@@ -90,7 +90,7 @@ pub(crate) fn readv(fd: BorrowedFd<'_>, bufs: &mut [IoSliceMut]) -> io::Result<u
 }
 
 #[cfg(not(target_os = "espidf"))]
-pub(crate) fn writev(fd: BorrowedFd<'_>, bufs: &[IoSlice]) -> io::Result<usize> {
+pub(crate) fn writev(fd: BorrowedFd<'_>, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
     unsafe {
         ret_usize(c::writev(
             borrowed_fd(fd),
@@ -109,7 +109,7 @@ pub(crate) fn writev(fd: BorrowedFd<'_>, bufs: &[IoSlice]) -> io::Result<usize>
 )))]
 pub(crate) fn preadv(
     fd: BorrowedFd<'_>,
-    bufs: &mut [IoSliceMut],
+    bufs: &mut [IoSliceMut<'_>],
     offset: u64,
 ) -> io::Result<usize> {
     // Silently cast; we'll get `EINVAL` if the value is negative.
@@ -131,7 +131,7 @@ pub(crate) fn preadv(
     target_os = "redox",
     target_os = "solaris"
 )))]
-pub(crate) fn pwritev(fd: BorrowedFd<'_>, bufs: &[IoSlice], offset: u64) -> io::Result<usize> {
+pub(crate) fn pwritev(fd: BorrowedFd<'_>, bufs: &[IoSlice<'_>], offset: u64) -> io::Result<usize> {
     // Silently cast; we'll get `EINVAL` if the value is negative.
     let offset = offset as i64;
     unsafe {
@@ -147,7 +147,7 @@ pub(crate) fn pwritev(fd: BorrowedFd<'_>, bufs: &[IoSlice], offset: u64) -> io::
 #[cfg(linux_kernel)]
 pub(crate) fn preadv2(
     fd: BorrowedFd<'_>,
-    bufs: &mut [IoSliceMut],
+    bufs: &mut [IoSliceMut<'_>],
     offset: u64,
     flags: ReadWriteFlags,
 ) -> io::Result<usize> {
@@ -167,7 +167,7 @@ pub(crate) fn preadv2(
 #[cfg(linux_kernel)]
 pub(crate) fn pwritev2(
     fd: BorrowedFd<'_>,
-    bufs: &[IoSlice],
+    bufs: &[IoSlice<'_>],
     offset: u64,
     flags: ReadWriteFlags,
 ) -> io::Result<usize> {

src/backend/libc/pipe/syscalls.rs

@@ -55,9 +55,9 @@ pub(crate) fn pipe_with(flags: PipeFlags) -> io::Result<(OwnedFd, OwnedFd)> {
 #[cfg(linux_kernel)]
 #[inline]
 pub fn splice(
-    fd_in: BorrowedFd,
+    fd_in: BorrowedFd<'_>,
     off_in: Option<&mut u64>,
-    fd_out: BorrowedFd,
+    fd_out: BorrowedFd<'_>,
     off_out: Option<&mut u64>,
     len: usize,
     flags: SpliceFlags,
@@ -80,8 +80,8 @@ pub fn splice(
 #[cfg(linux_kernel)]
 #[inline]
 pub unsafe fn vmsplice(
-    fd: BorrowedFd,
-    bufs: &[IoSliceRaw],
+    fd: BorrowedFd<'_>,
+    bufs: &[IoSliceRaw<'_>],
     flags: SpliceFlags,
 ) -> io::Result<usize> {
     ret_usize(c::vmsplice(
@@ -95,8 +95,8 @@ pub unsafe fn vmsplice(
 #[cfg(linux_kernel)]
 #[inline]
 pub fn tee(
-    fd_in: BorrowedFd,
-    fd_out: BorrowedFd,
+    fd_in: BorrowedFd<'_>,
+    fd_out: BorrowedFd<'_>,
     len: usize,
     flags: SpliceFlags,
 ) -> io::Result<usize> {

src/backend/libc/pty/syscalls.rs

@@ -29,7 +29,7 @@ pub(crate) fn openpt(flags: OpenptFlags) -> io::Result<OwnedFd> {
     any(apple, linux_like, target_os = "freebsd", target_os = "fuchsia")
 ))]
 #[inline]
-pub(crate) fn ptsname(fd: BorrowedFd, mut buffer: Vec<u8>) -> io::Result<CString> {
+pub(crate) fn ptsname(fd: BorrowedFd<'_>, mut buffer: Vec<u8>) -> io::Result<CString> {
     // This code would benefit from having a better way to read into
     // uninitialized memory, but that requires `unsafe`.
     buffer.clear();
@@ -93,12 +93,12 @@ pub(crate) fn ptsname(fd: BorrowedFd, mut buffer: Vec<u8>) -> io::Result<CString
 }
 
 #[inline]
-pub(crate) fn unlockpt(fd: BorrowedFd) -> io::Result<()> {
+pub(crate) fn unlockpt(fd: BorrowedFd<'_>) -> io::Result<()> {
     unsafe { ret(c::unlockpt(borrowed_fd(fd))) }
 }
 
 #[cfg(not(linux_kernel))]
 #[inline]
-pub(crate) fn grantpt(fd: BorrowedFd) -> io::Result<()> {
+pub(crate) fn grantpt(fd: BorrowedFd<'_>) -> io::Result<()> {
     unsafe { ret(c::grantpt(borrowed_fd(fd))) }
 }

src/backend/libc/termios/syscalls.rs

@@ -92,7 +92,7 @@ pub(crate) fn tcsetpgrp(fd: BorrowedFd<'_>, pid: Pid) -> io::Result<()> {
 
 #[cfg(not(any(target_os = "espidf", target_os = "wasi")))]
 pub(crate) fn tcsetattr(
-    fd: BorrowedFd,
+    fd: BorrowedFd<'_>,
     optional_actions: OptionalActions,
     termios: &Termios,
 ) -> io::Result<()> {
@@ -165,40 +165,40 @@ pub(crate) fn tcsetattr(
 }
 
 #[cfg(not(target_os = "wasi"))]
-pub(crate) fn tcsendbreak(fd: BorrowedFd) -> io::Result<()> {
+pub(crate) fn tcsendbreak(fd: BorrowedFd<'_>) -> io::Result<()> {
     unsafe { ret(c::tcsendbreak(borrowed_fd(fd), 0)) }
 }
 
 #[cfg(not(any(target_os = "espidf", target_os = "wasi")))]
-pub(crate) fn tcdrain(fd: BorrowedFd) -> io::Result<()> {
+pub(crate) fn tcdrain(fd: BorrowedFd<'_>) -> io::Result<()> {
     unsafe { ret(c::tcdrain(borrowed_fd(fd))) }
 }
 
 #[cfg(not(any(target_os = "espidf", target_os = "wasi")))]
-pub(crate) fn tcflush(fd: BorrowedFd, queue_selector: QueueSelector) -> io::Result<()> {
+pub(crate) fn tcflush(fd: BorrowedFd<'_>, queue_selector: QueueSelector) -> io::Result<()> {
     unsafe { ret(c::tcflush(borrowed_fd(fd), queue_selector as _)) }
 }
 
 #[cfg(not(any(target_os = "espidf", target_os = "wasi")))]
-pub(crate) fn tcflow(fd: BorrowedFd, action: Action) -> io::Result<()> {
+pub(crate) fn tcflow(fd: BorrowedFd<'_>, action: Action) -> io::Result<()> {
     unsafe { ret(c::tcflow(borrowed_fd(fd), action as _)) }
 }
 
 #[cfg(not(target_os = "wasi"))]
-pub(crate) fn tcgetsid(fd: BorrowedFd) -> io::Result<Pid> {
+pub(crate) fn tcgetsid(fd: BorrowedFd<'_>) -> io::Result<Pid> {
     unsafe {
         let pid = ret_pid_t(c::tcgetsid(borrowed_fd(fd)))?;
         Ok(Pid::from_raw_unchecked(pid))
     }
 }
 
 #[cfg(not(any(target_os = "espidf", target_os = "wasi")))]
-pub(crate) fn tcsetwinsize(fd: BorrowedFd, winsize: Winsize) -> io::Result<()> {
+pub(crate) fn tcsetwinsize(fd: BorrowedFd<'_>, winsize: Winsize) -> io::Result<()> {
     unsafe { ret(c::ioctl(borrowed_fd(fd), c::TIOCSWINSZ, &winsize)) }
 }
 
 #[cfg(not(any(target_os = "espidf", target_os = "wasi")))]
-pub(crate) fn tcgetwinsize(fd: BorrowedFd) -> io::Result<Winsize> {
+pub(crate) fn tcgetwinsize(fd: BorrowedFd<'_>) -> io::Result<Winsize> {
     unsafe {
         let mut buf = MaybeUninit::<Winsize>::uninit();
         ret(c::ioctl(

src/backend/libc/thread/syscalls.rs

@@ -280,7 +280,7 @@ pub(crate) fn gettid() -> Pid {
 
 #[cfg(linux_kernel)]
 #[inline]
-pub(crate) fn setns(fd: BorrowedFd, nstype: c::c_int) -> io::Result<c::c_int> {
+pub(crate) fn setns(fd: BorrowedFd<'_>, nstype: c::c_int) -> io::Result<c::c_int> {
     // `setns` wasn't supported in glibc until 2.14, and musl until 0.9.5,
     // so use `syscall`.
     weak_or_syscall! {

src/backend/linux_raw/arch/powerpc64.rs

@@ -15,7 +15,7 @@ use crate::backend::reg::{
 use core::arch::asm;
 
 #[inline]
-pub(in crate::backend) unsafe fn syscall0_readonly(nr: SyscallNumber) -> RetReg<R0> {
+pub(in crate::backend) unsafe fn syscall0_readonly(nr: SyscallNumber<'_>) -> RetReg<R0> {
     let r0;
     asm!(
         "sc",

src/backend/linux_raw/conv.rs

@@ -186,45 +186,45 @@ pub(super) fn no_fd<'a, Num: ArgNumber>() -> ArgReg<'a, Num> {
 }
 
 #[inline]
-pub(super) fn slice_just_addr<T: Sized, Num: ArgNumber>(v: &[T]) -> ArgReg<Num> {
+pub(super) fn slice_just_addr<T: Sized, Num: ArgNumber>(v: &[T]) -> ArgReg<'_, Num> {
     let mut_ptr = v.as_ptr() as *mut T;
     raw_arg(mut_ptr.cast())
 }
 
 #[inline]
-pub(super) fn slice_just_addr_mut<T: Sized, Num: ArgNumber>(v: &mut [T]) -> ArgReg<Num> {
+pub(super) fn slice_just_addr_mut<T: Sized, Num: ArgNumber>(v: &mut [T]) -> ArgReg<'_, Num> {
     raw_arg(v.as_mut_ptr().cast())
 }
 
 #[inline]
 pub(super) fn slice<T: Sized, Num0: ArgNumber, Num1: ArgNumber>(
     v: &[T],
-) -> (ArgReg<Num0>, ArgReg<Num1>) {
+) -> (ArgReg<'_, Num0>, ArgReg<'_, Num1>) {
     (slice_just_addr(v), pass_usize(v.len()))
 }
 
 #[inline]
 pub(super) fn slice_mut<T: Sized, Num0: ArgNumber, Num1: ArgNumber>(
     v: &mut [T],
-) -> (ArgReg<Num0>, ArgReg<Num1>) {
+) -> (ArgReg<'_, Num0>, ArgReg<'_, Num1>) {
     (raw_arg(v.as_mut_ptr().cast()), pass_usize(v.len()))
 }
 
 #[inline]
-pub(super) fn by_ref<T: Sized, Num: ArgNumber>(t: &T) -> ArgReg<Num> {
+pub(super) fn by_ref<T: Sized, Num: ArgNumber>(t: &T) -> ArgReg<'_, Num> {
     let mut_ptr = as_ptr(t) as *mut T;
     raw_arg(mut_ptr.cast())
 }
 
 #[inline]
-pub(super) fn by_mut<T: Sized, Num: ArgNumber>(t: &mut T) -> ArgReg<Num> {
+pub(super) fn by_mut<T: Sized, Num: ArgNumber>(t: &mut T) -> ArgReg<'_, Num> {
     raw_arg(as_mut_ptr(t).cast())
 }
 
 /// Convert an optional mutable reference into a `usize` for passing to a
 /// syscall.
 #[inline]
-pub(super) fn opt_mut<T: Sized, Num: ArgNumber>(t: Option<&mut T>) -> ArgReg<Num> {
+pub(super) fn opt_mut<T: Sized, Num: ArgNumber>(t: Option<&mut T>) -> ArgReg<'_, Num> {
     // This optimizes into the equivalent of `transmute(t)`, and has the
     // advantage of not requiring `unsafe`.
     match t {
@@ -237,7 +237,7 @@ pub(super) fn opt_mut<T: Sized, Num: ArgNumber>(t: Option<&mut T>) -> ArgReg<Num
 /// syscall.
 #[cfg(any(target_arch = "aarch64", target_arch = "riscv64"))]
 #[inline]
-pub(super) fn opt_ref<T: Sized, Num: ArgNumber>(t: Option<&T>) -> ArgReg<Num> {
+pub(super) fn opt_ref<T: Sized, Num: ArgNumber>(t: Option<&T>) -> ArgReg<'_, Num> {
     // This optimizes into the equivalent of `transmute(t)`, and has the
     // advantage of not requiring `unsafe`.
     match t {

src/backend/linux_raw/io/syscalls.rs

@@ -10,12 +10,7 @@
 use crate::backend::conv::loff_t_from_u64;
 #[cfg(all(
     target_pointer_width = "32",
-    any(
-        target_arch = "arm",
-        target_arch = "mips",
-        target_arch = "mips32r6",
-        target_arch = "power"
-    ),
+    any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6"),
 ))]
 use crate::backend::conv::zero;
 use crate::backend::conv::{
@@ -47,12 +42,7 @@ pub(crate) fn pread(fd: BorrowedFd<'_>, buf: &mut [u8], pos: u64) -> io::Result<
     // <https://github.com/torvalds/linux/blob/fcadab740480e0e0e9fa9bd272acd409884d431a/arch/arm64/kernel/sys32.c#L75>
     #[cfg(all(
         target_pointer_width = "32",
-        any(
-            target_arch = "arm",
-            target_arch = "mips",
-            target_arch = "mips32r6",
-            target_arch = "power"
-        ),
+        any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6"),
     ))]
     unsafe {
         ret_usize(syscall!(
@@ -67,12 +57,7 @@ pub(crate) fn pread(fd: BorrowedFd<'_>, buf: &mut [u8], pos: u64) -> io::Result<
     }
     #[cfg(all(
         target_pointer_width = "32",
-        not(any(
-            target_arch = "arm",
-            target_arch = "mips",
-            target_arch = "mips32r6",
-            target_arch = "power"
-        )),
+        not(any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6")),
     ))]
     unsafe {
         ret_usize(syscall!(
@@ -182,12 +167,7 @@ pub(crate) fn pwrite(fd: BorrowedFd<'_>, buf: &[u8], pos: u64) -> io::Result<usi
     // <https://github.com/torvalds/linux/blob/fcadab740480e0e0e9fa9bd272acd409884d431a/arch/arm64/kernel/sys32.c#L81-L83>
     #[cfg(all(
         target_pointer_width = "32",
-        any(
-            target_arch = "arm",
-            target_arch = "mips",
-            target_arch = "mips32r6",
-            target_arch = "power"
-        ),
+        any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6"),
     ))]
     unsafe {
         ret_usize(syscall_readonly!(
@@ -202,12 +182,7 @@ pub(crate) fn pwrite(fd: BorrowedFd<'_>, buf: &[u8], pos: u64) -> io::Result<usi
     }
     #[cfg(all(
         target_pointer_width = "32",
-        not(any(
-            target_arch = "arm",
-            target_arch = "mips",
-            target_arch = "mips32r6",
-            target_arch = "power"
-        )),
+        not(any(target_arch = "arm", target_arch = "mips", target_arch = "mips32r6")),
     ))]
     unsafe {
         ret_usize(syscall_readonly!(