Auto merge of #118154 - ChrisDenton:win-clippy, r=scottmcm

Fix some clippy lints for library/std/src/sys/windows

These issues were shown by running `x clippy` on `library/std` and filtering for `windows/` paths. I think running clippy on the full std would be great but I wanted to start smaller and with something that's hopefully easier to review. It'd be good to eventually run clippy in CI but that's a bigger conversation.

I've created separate commits for each clippy lint fixed (with the commit title set to the lint name) and reviewed the changes myself. Most of the fixes here are trivial.

r? libs

14 files changed, 43 insertions, 45 deletions

diff --git a/library/std/src/os/windows/io/handle.rs b/library/std/src/os/windows/io/handle.rs
index 274af08a388..b0540872c0b 100644
--- a/library/std/src/os/windows/io/handle.rs
+++ b/library/std/src/os/windows/io/handle.rs
@@ -504,7 +504,7 @@ impl AsHandle for fs::File {
 impl From<fs::File> for OwnedHandle {
     #[inline]
     fn from(file: fs::File) -> OwnedHandle {
-        file.into_inner().into_inner().into_inner().into()
+        file.into_inner().into_inner().into_inner()
     }
 }
 
diff --git a/library/std/src/os/windows/io/socket.rs b/library/std/src/os/windows/io/socket.rs
index c80b9e28499..65f161f32e7 100644
--- a/library/std/src/os/windows/io/socket.rs
+++ b/library/std/src/os/windows/io/socket.rs
@@ -127,7 +127,7 @@ impl BorrowedSocket<'_> {
                 info.iAddressFamily,
                 info.iSocketType,
                 info.iProtocol,
-                &mut info,
+                &info,
                 0,
                 sys::c::WSA_FLAG_OVERLAPPED | sys::c::WSA_FLAG_NO_HANDLE_INHERIT,
             )
@@ -147,7 +147,7 @@ impl BorrowedSocket<'_> {
                     info.iAddressFamily,
                     info.iSocketType,
                     info.iProtocol,
-                    &mut info,
+                    &info,
                     0,
                     sys::c::WSA_FLAG_OVERLAPPED,
                 )
diff --git a/library/std/src/sys/windows/api.rs b/library/std/src/sys/windows/api.rs
index e9f0bbfbe2e..72ecb950341 100644
--- a/library/std/src/sys/windows/api.rs
+++ b/library/std/src/sys/windows/api.rs
@@ -132,7 +132,7 @@ pub fn set_file_information_by_handle<T: SetFileInformation>(
         size: u32,
     ) -> Result<(), WinError> {
         let result = c::SetFileInformationByHandle(handle, class, info, size);
-        (result != 0).then_some(()).ok_or_else(|| get_last_error())
+        (result != 0).then_some(()).ok_or_else(get_last_error)
     }
     // SAFETY: The `SetFileInformation` trait ensures that this is safe.
     unsafe { set_info(handle, T::CLASS, info.as_ptr(), info.size()) }
diff --git a/library/std/src/sys/windows/c.rs b/library/std/src/sys/windows/c.rs
index a349e24b039..351ec2a48be 100644
--- a/library/std/src/sys/windows/c.rs
+++ b/library/std/src/sys/windows/c.rs
@@ -3,6 +3,7 @@
 #![allow(nonstandard_style)]
 #![cfg_attr(test, allow(dead_code))]
 #![unstable(issue = "none", feature = "windows_c")]
+#![allow(clippy::style)]
 
 use crate::ffi::CStr;
 use crate::mem;
@@ -81,7 +82,7 @@ pub fn nt_success(status: NTSTATUS) -> bool {
 
 impl UNICODE_STRING {
     pub fn from_ref(slice: &[u16]) -> Self {
-        let len = slice.len() * mem::size_of::<u16>();
+        let len = mem::size_of_val(slice);
         Self { Length: len as _, MaximumLength: len as _, Buffer: slice.as_ptr() as _ }
     }
 }
diff --git a/library/std/src/sys/windows/fs.rs b/library/std/src/sys/windows/fs.rs
index d7e36b9a3ff..f57034cc8d5 100644
--- a/library/std/src/sys/windows/fs.rs
+++ b/library/std/src/sys/windows/fs.rs
@@ -156,7 +156,7 @@ impl DirEntry {
     }
 
     pub fn path(&self) -> PathBuf {
-        self.root.join(&self.file_name())
+        self.root.join(self.file_name())
     }
 
     pub fn file_name(&self) -> OsString {
@@ -548,7 +548,7 @@ impl File {
                 let user = super::args::from_wide_to_user_path(
                     subst.iter().copied().chain([0]).collect(),
                 )?;
-                Ok(PathBuf::from(OsString::from_wide(&user.strip_suffix(&[0]).unwrap_or(&user))))
+                Ok(PathBuf::from(OsString::from_wide(user.strip_suffix(&[0]).unwrap_or(&user))))
             } else {
                 Ok(PathBuf::from(OsString::from_wide(subst)))
             }
@@ -786,7 +786,7 @@ fn open_link_no_reparse(parent: &File, name: &[u16], access: u32) -> io::Result<
         // tricked into following a symlink. However, it may not be available in
         // earlier versions of Windows.
         static ATTRIBUTES: AtomicU32 = AtomicU32::new(c::OBJ_DONT_REPARSE);
-        let mut object = c::OBJECT_ATTRIBUTES {
+        let object = c::OBJECT_ATTRIBUTES {
             ObjectName: &mut name_str,
             RootDirectory: parent.as_raw_handle(),
             Attributes: ATTRIBUTES.load(Ordering::Relaxed),
@@ -795,7 +795,7 @@ fn open_link_no_reparse(parent: &File, name: &[u16], access: u32) -> io::Result<
         let status = c::NtCreateFile(
             &mut handle,
             access,
-            &mut object,
+            &object,
             &mut io_status,
             crate::ptr::null_mut(),
             0,
@@ -874,7 +874,7 @@ impl fmt::Debug for File {
         // FIXME(#24570): add more info here (e.g., mode)
         let mut b = f.debug_struct("File");
         b.field("handle", &self.handle.as_raw_handle());
-        if let Ok(path) = get_path(&self) {
+        if let Ok(path) = get_path(self) {
             b.field("path", &path);
         }
         b.finish()
@@ -1193,7 +1193,7 @@ pub fn readlink(path: &Path) -> io::Result<PathBuf> {
     let mut opts = OpenOptions::new();
     opts.access_mode(0);
     opts.custom_flags(c::FILE_FLAG_OPEN_REPARSE_POINT | c::FILE_FLAG_BACKUP_SEMANTICS);
-    let file = File::open(&path, &opts)?;
+    let file = File::open(path, &opts)?;
     file.readlink()
 }
 
@@ -1407,7 +1407,7 @@ pub fn symlink_junction<P: AsRef<Path>, Q: AsRef<Path>>(
 #[allow(dead_code)]
 fn symlink_junction_inner(original: &Path, junction: &Path) -> io::Result<()> {
     let d = DirBuilder::new();
-    d.mkdir(&junction)?;
+    d.mkdir(junction)?;
 
     let mut opts = OpenOptions::new();
     opts.write(true);
diff --git a/library/std/src/sys/windows/handle.rs b/library/std/src/sys/windows/handle.rs
index 56d0d6c0887..c4495f81a5a 100644
--- a/library/std/src/sys/windows/handle.rs
+++ b/library/std/src/sys/windows/handle.rs
@@ -81,7 +81,7 @@ impl Handle {
         let res = unsafe { self.synchronous_read(buf.as_mut_ptr().cast(), buf.len(), None) };
 
         match res {
-            Ok(read) => Ok(read as usize),
+            Ok(read) => Ok(read),
 
             // The special treatment of BrokenPipe is to deal with Windows
             // pipe semantics, which yields this error when *reading* from
@@ -107,7 +107,7 @@ impl Handle {
             unsafe { self.synchronous_read(buf.as_mut_ptr().cast(), buf.len(), Some(offset)) };
 
         match res {
-            Ok(read) => Ok(read as usize),
+            Ok(read) => Ok(read),
             Err(ref e) if e.raw_os_error() == Some(c::ERROR_HANDLE_EOF as i32) => Ok(0),
             Err(e) => Err(e),
         }
@@ -121,7 +121,7 @@ impl Handle {
             Ok(read) => {
                 // Safety: `read` bytes were written to the initialized portion of the buffer
                 unsafe {
-                    cursor.advance(read as usize);
+                    cursor.advance(read);
                 }
                 Ok(())
             }
@@ -189,7 +189,7 @@ impl Handle {
     }
 
     pub fn write(&self, buf: &[u8]) -> io::Result<usize> {
-        self.synchronous_write(&buf, None)
+        self.synchronous_write(buf, None)
     }
 
     pub fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
@@ -202,7 +202,7 @@ impl Handle {
     }
 
     pub fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
-        self.synchronous_write(&buf, Some(offset))
+        self.synchronous_write(buf, Some(offset))
     }
 
     pub fn try_clone(&self) -> io::Result<Self> {
diff --git a/library/std/src/sys/windows/io.rs b/library/std/src/sys/windows/io.rs
index 9b540ee071f..649826d25ce 100644
--- a/library/std/src/sys/windows/io.rs
+++ b/library/std/src/sys/windows/io.rs
@@ -36,7 +36,7 @@ impl<'a> IoSlice<'a> {
 
     #[inline]
     pub fn as_slice(&self) -> &[u8] {
-        unsafe { slice::from_raw_parts(self.vec.buf as *mut u8, self.vec.len as usize) }
+        unsafe { slice::from_raw_parts(self.vec.buf, self.vec.len as usize) }
     }
 }
 
@@ -70,12 +70,12 @@ impl<'a> IoSliceMut<'a> {
 
     #[inline]
     pub fn as_slice(&self) -> &[u8] {
-        unsafe { slice::from_raw_parts(self.vec.buf as *mut u8, self.vec.len as usize) }
+        unsafe { slice::from_raw_parts(self.vec.buf, self.vec.len as usize) }
     }
 
     #[inline]
     pub fn as_mut_slice(&mut self) -> &mut [u8] {
-        unsafe { slice::from_raw_parts_mut(self.vec.buf as *mut u8, self.vec.len as usize) }
+        unsafe { slice::from_raw_parts_mut(self.vec.buf, self.vec.len as usize) }
     }
 }
 
diff --git a/library/std/src/sys/windows/mod.rs b/library/std/src/sys/windows/mod.rs
index c4e56e13be3..9c83d6eb8bf 100644
--- a/library/std/src/sys/windows/mod.rs
+++ b/library/std/src/sys/windows/mod.rs
@@ -63,7 +63,7 @@ pub unsafe fn init(_argc: isize, _argv: *const *const u8, _sigpipe: u8) {
 
     // Normally, `thread::spawn` will call `Thread::set_name` but since this thread already
     // exists, we have to call it ourselves.
-    thread::Thread::set_name(&CStr::from_bytes_with_nul_unchecked(b"main\0"));
+    thread::Thread::set_name(CStr::from_bytes_with_nul_unchecked(b"main\0"));
 }
 
 // SAFETY: must be called only once during runtime cleanup.
@@ -150,7 +150,7 @@ pub fn decode_error_kind(errno: i32) -> ErrorKind {
 
 pub fn unrolled_find_u16s(needle: u16, haystack: &[u16]) -> Option<usize> {
     let ptr = haystack.as_ptr();
-    let mut start = &haystack[..];
+    let mut start = haystack;
 
     // For performance reasons unfold the loop eight times.
     while start.len() >= 8 {
diff --git a/library/std/src/sys/windows/net.rs b/library/std/src/sys/windows/net.rs
index c29b863665f..6cd758ec5c3 100644
--- a/library/std/src/sys/windows/net.rs
+++ b/library/std/src/sys/windows/net.rs
@@ -162,7 +162,7 @@ impl Socket {
 
                 let mut timeout = c::timeval {
                     tv_sec: cmp::min(timeout.as_secs(), c_long::MAX as u64) as c_long,
-                    tv_usec: (timeout.subsec_nanos() / 1000) as c_long,
+                    tv_usec: timeout.subsec_micros() as c_long,
                 };
 
                 if timeout.tv_sec == 0 && timeout.tv_usec == 0 {
diff --git a/library/std/src/sys/windows/os.rs b/library/std/src/sys/windows/os.rs
index 8cc905101de..829dd5eb97a 100644
--- a/library/std/src/sys/windows/os.rs
+++ b/library/std/src/sys/windows/os.rs
@@ -297,7 +297,7 @@ pub fn getenv(k: &OsStr) -> Option<OsString> {
     let k = to_u16s(k).ok()?;
     super::fill_utf16_buf(
         |buf, sz| unsafe { c::GetEnvironmentVariableW(k.as_ptr(), buf, sz) },
-        |buf| OsStringExt::from_wide(buf),
+        OsStringExt::from_wide,
     )
     .ok()
 }
@@ -356,7 +356,7 @@ pub fn home_dir() -> Option<PathBuf> {
     crate::env::var_os("HOME")
         .or_else(|| crate::env::var_os("USERPROFILE"))
         .map(PathBuf::from)
-        .or_else(|| home_dir_crt())
+        .or_else(home_dir_crt)
 }
 
 pub fn exit(code: i32) -> ! {
@@ -364,5 +364,5 @@ pub fn exit(code: i32) -> ! {
 }
 
 pub fn getpid() -> u32 {
-    unsafe { c::GetCurrentProcessId() as u32 }
+    unsafe { c::GetCurrentProcessId() }
 }
diff --git a/library/std/src/sys/windows/path.rs b/library/std/src/sys/windows/path.rs
index f7f9f96ba5d..d9684f21753 100644
--- a/library/std/src/sys/windows/path.rs
+++ b/library/std/src/sys/windows/path.rs
@@ -78,7 +78,7 @@ impl<'a> PrefixParserSlice<'a, '_> {
     fn strip_prefix(&self, prefix: &str) -> Option<Self> {
         self.prefix[self.index..]
             .starts_with(prefix.as_bytes())
-            .then(|| Self { index: self.index + prefix.len(), ..*self })
+            .then_some(Self { index: self.index + prefix.len(), ..*self })
     }
 
     fn prefix_bytes(&self) -> &'a [u8] {
@@ -147,12 +147,10 @@ pub fn parse_prefix(path: &OsStr) -> Option<Prefix<'_>> {
                 None
             }
         }
-    } else if let Some(drive) = parse_drive(path) {
-        // C:
-        Some(Disk(drive))
     } else {
-        // no prefix
-        None
+        // If it has a drive like `C:` then it's a disk.
+        // Otherwise there is no prefix.
+        parse_drive(path).map(Disk)
     }
 }
 
@@ -252,7 +250,7 @@ pub(crate) fn get_long_path(mut path: Vec<u16>, prefer_verbatim: bool) -> io::Re
     // \\?\UNC\
     const UNC_PREFIX: &[u16] = &[SEP, SEP, QUERY, SEP, U, N, C, SEP];
 
-    if path.starts_with(VERBATIM_PREFIX) || path.starts_with(NT_PREFIX) || path == &[0] {
+    if path.starts_with(VERBATIM_PREFIX) || path.starts_with(NT_PREFIX) || path == [0] {
         // Early return for paths that are already verbatim or empty.
         return Ok(path);
     } else if path.len() < LEGACY_MAX_PATH {
diff --git a/library/std/src/sys/windows/process.rs b/library/std/src/sys/windows/process.rs
index f4078d35944..51e16b9f13c 100644
--- a/library/std/src/sys/windows/process.rs
+++ b/library/std/src/sys/windows/process.rs
@@ -245,7 +245,7 @@ impl Command {
     }
 
     pub fn get_current_dir(&self) -> Option<&Path> {
-        self.cwd.as_ref().map(|cwd| Path::new(cwd))
+        self.cwd.as_ref().map(Path::new)
     }
 
     pub unsafe fn raw_attribute<T: Copy + Send + Sync + 'static>(
@@ -463,7 +463,7 @@ fn resolve_exe<'a>(
 
         // Search the directories given by `search_paths`.
         let result = search_paths(parent_paths, child_paths, |mut path| {
-            path.push(&exe_path);
+            path.push(exe_path);
             if !has_extension {
                 path.set_extension(EXE_EXTENSION);
             }
@@ -657,7 +657,7 @@ impl Process {
     }
 
     pub fn id(&self) -> u32 {
-        unsafe { c::GetProcessId(self.handle.as_raw_handle()) as u32 }
+        unsafe { c::GetProcessId(self.handle.as_raw_handle()) }
     }
 
     pub fn main_thread_handle(&self) -> BorrowedHandle<'_> {
@@ -917,9 +917,8 @@ fn make_proc_thread_attribute_list(
         )
     };
 
-    let mut proc_thread_attribute_list = ProcThreadAttributeList(
-        vec![MaybeUninit::uninit(); required_size as usize].into_boxed_slice(),
-    );
+    let mut proc_thread_attribute_list =
+        ProcThreadAttributeList(vec![MaybeUninit::uninit(); required_size].into_boxed_slice());
 
     // Once we've allocated the necessary memory, it's safe to invoke
     // `InitializeProcThreadAttributeList` to properly initialize the list.
diff --git a/library/std/src/sys/windows/stdio.rs b/library/std/src/sys/windows/stdio.rs
index a9ff909aa67..819a48266d9 100644
--- a/library/std/src/sys/windows/stdio.rs
+++ b/library/std/src/sys/windows/stdio.rs
@@ -195,7 +195,7 @@ fn write_valid_utf8_to_console(handle: c::HANDLE, utf8: &str) -> io::Result<usiz
         MaybeUninit::slice_assume_init_ref(&utf16[..result as usize])
     };
 
-    let mut written = write_u16s(handle, &utf16)?;
+    let mut written = write_u16s(handle, utf16)?;
 
     // Figure out how many bytes of as UTF-8 were written away as UTF-16.
     if written == utf16.len() {
@@ -207,7 +207,7 @@ fn write_valid_utf8_to_console(handle: c::HANDLE, utf8: &str) -> io::Result<usiz
         // write the missing surrogate out now.
         // Buffering it would mean we have to lie about the number of bytes written.
         let first_code_unit_remaining = utf16[written];
-        if first_code_unit_remaining >= 0xDCEE && first_code_unit_remaining <= 0xDFFF {
+        if matches!(first_code_unit_remaining, 0xDCEE..=0xDFFF) {
             // low surrogate
             // We just hope this works, and give up otherwise
             let _ = write_u16s(handle, &utf16[written..written + 1]);
@@ -266,7 +266,7 @@ impl io::Read for Stdin {
         let mut bytes_copied = self.incomplete_utf8.read(buf);
 
         if bytes_copied == buf.len() {
-            return Ok(bytes_copied);
+            Ok(bytes_copied)
         } else if buf.len() - bytes_copied < 4 {
             // Not enough space to get a UTF-8 byte. We will use the incomplete UTF8.
             let mut utf16_buf = [MaybeUninit::new(0); 1];
@@ -332,7 +332,7 @@ fn read_u16s_fixup_surrogates(
         // and it is not 0, so we know that `buf[amount - 1]` have been
         // initialized.
         let last_char = unsafe { buf[amount - 1].assume_init() };
-        if last_char >= 0xD800 && last_char <= 0xDBFF {
+        if matches!(last_char, 0xD800..=0xDBFF) {
             // high surrogate
             *surrogate = last_char;
             amount -= 1;
diff --git a/library/std/src/sys/windows/time.rs b/library/std/src/sys/windows/time.rs
index bece48e799f..09e78a29304 100644
--- a/library/std/src/sys/windows/time.rs
+++ b/library/std/src/sys/windows/time.rs
@@ -1,7 +1,7 @@
 use crate::cmp::Ordering;
 use crate::fmt;
 use crate::mem;
-use crate::ptr::{null, null_mut};
+use crate::ptr::null;
 use crate::sys::c;
 use crate::sys_common::IntoInner;
 use crate::time::Duration;
@@ -240,7 +240,7 @@ impl WaitableTimer {
                 c::TIMER_ALL_ACCESS,
             )
         };
-        if handle != null_mut() { Ok(Self { handle }) } else { Err(()) }
+        if !handle.is_null() { Ok(Self { handle }) } else { Err(()) }
     }
     pub fn set(&self, duration: Duration) -> Result<(), ()> {
         // Convert the Duration to a format similar to FILETIME.