Fix some clippy warnings

Fixed with `cargo clippy --features unix  --fix`
and manually

src/uu/chgrp/src/chgrp.rs

@@ -27,7 +27,7 @@ const USAGE: &str = "\
 
 fn parse_gid_and_uid(matches: &ArgMatches) -> UResult<(Option<u32>, Option<u32>, IfFrom)> {
     let dest_gid = if let Some(file) = matches.get_one::<String>(options::REFERENCE) {
-        fs::metadata(&file)
+        fs::metadata(file)
             .map(|meta| Some(meta.gid()))
             .map_err_context(|| format!("failed to get attributes of {}", file.quote()))?
     } else {

src/uu/chown/src/chown.rs

@@ -40,7 +40,7 @@ fn parse_gid_uid_and_filter(matches: &ArgMatches) -> UResult<(Option<u32>, Optio
     let dest_uid: Option<u32>;
     let dest_gid: Option<u32>;
     if let Some(file) = matches.get_one::<String>(options::REFERENCE) {
-        let meta = fs::metadata(&file)
+        let meta = fs::metadata(file)
             .map_err_context(|| format!("failed to get attributes of {}", file.quote()))?;
         dest_gid = Some(meta.gid());
         dest_uid = Some(meta.uid());

src/uu/comm/src/comm.rs

@@ -124,7 +124,7 @@ fn open_file(name: &str) -> io::Result<LineReader> {
     match name {
         "-" => Ok(LineReader::Stdin(stdin())),
         _ => {
-            let f = File::open(&Path::new(name))?;
+            let f = File::open(Path::new(name))?;
             Ok(LineReader::FileIn(BufReader::new(f)))
         }
     }

src/uu/cp/src/cp.rs

@@ -1115,7 +1115,7 @@ fn copy_directory(
         .follow_links(options.dereference)
     {
         let p = or_continue!(path);
-        let path = current_dir.join(&p.path());
+        let path = current_dir.join(p.path());
 
         let local_to_root_parent = match root_parent {
             Some(parent) => {
@@ -1131,7 +1131,7 @@ fn copy_directory(
                 }
                 #[cfg(not(windows))]
                 {
-                    or_continue!(path.strip_prefix(&parent)).to_path_buf()
+                    or_continue!(path.strip_prefix(parent)).to_path_buf()
                 }
             }
             None => path.clone(),
@@ -1351,7 +1351,7 @@ fn context_for(src: &Path, dest: &Path) -> String {
 /// Implements a simple backup copy for the destination file.
 /// TODO: for the backup, should this function be replaced by `copy_file(...)`?
 fn backup_dest(dest: &Path, backup_path: &Path) -> CopyResult<PathBuf> {
-    fs::copy(dest, &backup_path)?;
+    fs::copy(dest, backup_path)?;
     Ok(backup_path.into())
 }
 
@@ -1566,7 +1566,7 @@ fn copy_file(
                 .write(true)
                 .truncate(false)
                 .create(true)
-                .open(&dest)
+                .open(dest)
                 .unwrap();
         }
     };
@@ -1630,7 +1630,7 @@ fn copy_helper(
 fn copy_fifo(dest: &Path, overwrite: OverwriteMode) -> CopyResult<()> {
     if dest.exists() {
         overwrite.verify(dest)?;
-        fs::remove_file(&dest)?;
+        fs::remove_file(dest)?;
     }
 
     let name = CString::new(dest.as_os_str().as_bytes()).unwrap();
@@ -1647,7 +1647,7 @@ fn copy_link(
     symlinked_files: &mut HashSet<FileInformation>,
 ) -> CopyResult<()> {
     // Here, we will copy the symlink itself (actually, just recreate it)
-    let link = fs::read_link(&source)?;
+    let link = fs::read_link(source)?;
     let dest: Cow<'_, Path> = if dest.is_dir() {
         match source.file_name() {
             Some(name) => dest.join(name).into(),
@@ -1695,8 +1695,8 @@ pub fn verify_target_type(target: &Path, target_type: &TargetType) -> CopyResult
 /// ).unwrap() == Path::new("target/c.txt"))
 /// ```
 pub fn localize_to_target(root: &Path, source: &Path, target: &Path) -> CopyResult<PathBuf> {
-    let local_to_root = source.strip_prefix(&root)?;
-    Ok(target.join(&local_to_root))
+    let local_to_root = source.strip_prefix(root)?;
+    Ok(target.join(local_to_root))
 }
 
 pub fn path_has_prefix(p1: &Path, p2: &Path) -> io::Result<bool> {

src/uu/cut/src/cut.rs

@@ -368,7 +368,7 @@ fn cut_files(mut filenames: Vec<String>, mode: &Mode) -> UResult<()> {
                 continue;
             }
 
-            show_if_err!(File::open(&path)
+            show_if_err!(File::open(path)
                 .map_err_context(|| filename.maybe_quote().to_string())
                 .and_then(|file| {
                     match &mode {

src/uu/du/src/du.rs

@@ -492,7 +492,7 @@ fn build_exclude_patterns(matches: &ArgMatches) -> UResult<Vec<Pattern>> {
     let exclude_from_iterator = matches
         .get_many::<String>(options::EXCLUDE_FROM)
         .unwrap_or_default()
-        .flat_map(|f| file_as_vec(&f));
+        .flat_map(file_as_vec);
 
     let excludes_iterator = matches
         .get_many::<String>(options::EXCLUDE)
@@ -913,7 +913,7 @@ impl FromStr for Threshold {
     type Err = ParseSizeError;
 
     fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
-        let offset = if s.starts_with(&['-', '+'][..]) { 1 } else { 0 };
+        let offset = usize::from(s.starts_with(&['-', '+'][..]));
 
         let size = parse_size(&s[offset..])?;
 

src/uu/expr/src/syntax_tree.rs

@@ -505,11 +505,7 @@ fn prefix_operator_substr(values: &[String]) -> String {
 }
 
 fn bool_as_int(b: bool) -> u8 {
-    if b {
-        1
-    } else {
-        0
-    }
+    u8::from(b)
 }
 fn bool_as_string(b: bool) -> String {
     if b {

src/uu/mktemp/src/mktemp.rs

@@ -275,7 +275,7 @@ impl Params {
         // For example, if `tmpdir` is "a/b" and the template is "c/dXXX",
         // then `prefix` is "a/b/c/d".
         let tmpdir = options.tmpdir;
-        let prefix_from_option = tmpdir.clone().unwrap_or_else(|| "".to_string());
+        let prefix_from_option = tmpdir.clone().unwrap_or_default();
         let prefix_from_template = &options.template[..i];
         let prefix = Path::new(&prefix_from_option)
             .join(prefix_from_template)
@@ -311,7 +311,7 @@ impl Params {
         //
         // For example, if the suffix command-line argument is ".txt" and
         // the template is "XXXabc", then `suffix` is "abc.txt".
-        let suffix_from_option = options.suffix.unwrap_or_else(|| "".to_string());
+        let suffix_from_option = options.suffix.unwrap_or_default();
         let suffix_from_template = &options.template[j..];
         let suffix = format!("{}{}", suffix_from_template, suffix_from_option);
         if suffix.contains(MAIN_SEPARATOR) {
@@ -484,7 +484,7 @@ pub fn dry_exec(tmpdir: &str, prefix: &str, rand: usize, suffix: &str) -> UResul
 fn make_temp_dir(dir: &str, prefix: &str, rand: usize, suffix: &str) -> UResult<PathBuf> {
     let mut builder = Builder::new();
     builder.prefix(prefix).rand_bytes(rand).suffix(suffix);
-    match builder.tempdir_in(&dir) {
+    match builder.tempdir_in(dir) {
         Ok(d) => {
             // `into_path` consumes the TempDir without removing it
             let path = d.into_path();
@@ -516,7 +516,7 @@ fn make_temp_dir(dir: &str, prefix: &str, rand: usize, suffix: &str) -> UResult<
 fn make_temp_file(dir: &str, prefix: &str, rand: usize, suffix: &str) -> UResult<PathBuf> {
     let mut builder = Builder::new();
     builder.prefix(prefix).rand_bytes(rand).suffix(suffix);
-    match builder.tempfile_in(&dir) {
+    match builder.tempfile_in(dir) {
         // `keep` ensures that the file is not deleted
         Ok(named_tempfile) => match named_tempfile.keep() {
             Ok((_, pathbuf)) => Ok(pathbuf),

src/uu/mv/src/mv.rs

@@ -453,7 +453,7 @@ fn rename_symlink_fallback(from: &Path, to: &Path) -> io::Result<()> {
     let path_symlink_points_to = fs::read_link(from)?;
     #[cfg(unix)]
     {
-        unix::fs::symlink(&path_symlink_points_to, &to).and_then(|_| fs::remove_file(&from))?;
+        unix::fs::symlink(&path_symlink_points_to, to).and_then(|_| fs::remove_file(from))?;
     }
     #[cfg(windows)]
     {

src/uu/nl/src/nl.rs

@@ -279,7 +279,7 @@ fn nl<T: Read>(reader: &mut BufReader<T>, settings: &Settings) -> UResult<()> {
             // If we have already seen three groups (corresponding to
             // a header) or the current char does not form part of
             // a new group, then this line is not a segment indicator.
-            if matched_groups >= 3 || settings.section_delimiter[if odd { 1 } else { 0 }] != c {
+            if matched_groups >= 3 || settings.section_delimiter[usize::from(odd)] != c {
                 matched_groups = 0;
                 break;
             }

src/uu/sort/src/sort.rs

@@ -1086,7 +1086,7 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
 
         let mut files = Vec::new();
         for path in &files0_from {
-            let reader = open(&path)?;
+            let reader = open(path)?;
             let buf_reader = BufReader::new(reader);
             for line in buf_reader.split(b'\0').flatten() {
                 files.push(OsString::from(

src/uu/sort/src/tmp_dir.rs

@@ -80,7 +80,7 @@ impl TmpDirWrapper {
 /// Remove the directory at `path` by deleting its child files and then itself.
 /// Errors while deleting child files are ignored.
 fn remove_tmp_dir(path: &Path) -> std::io::Result<()> {
-    if let Ok(read_dir) = std::fs::read_dir(&path) {
+    if let Ok(read_dir) = std::fs::read_dir(path) {
         for file in read_dir.flatten() {
             // if we fail to delete the file here it was probably deleted by another thread
             // in the meantime, but that's ok.

src/uu/split/src/platform/unix.rs

@@ -56,7 +56,7 @@ impl Drop for WithEnvVarSet {
     /// Restore previous value now that this is being dropped by context
     fn drop(&mut self) {
         if let Ok(ref prev_value) = self._previous_var_value {
-            env::set_var(&self._previous_var_key, &prev_value);
+            env::set_var(&self._previous_var_key, prev_value);
         } else {
             env::remove_var(&self._previous_var_key);
         }

src/uu/stdbuf/src/stdbuf.rs

@@ -207,7 +207,7 @@ pub fn uu_app<'a>() -> Command<'a> {
                 .short(options::INPUT_SHORT)
                 .help("adjust standard input stream buffering")
                 .value_name("MODE")
-                .required_unless_present_any(&[options::OUTPUT, options::ERROR]),
+                .required_unless_present_any([options::OUTPUT, options::ERROR]),
         )
         .arg(
             Arg::new(options::OUTPUT)
@@ -215,7 +215,7 @@ pub fn uu_app<'a>() -> Command<'a> {
                 .short(options::OUTPUT_SHORT)
                 .help("adjust standard output stream buffering")
                 .value_name("MODE")
-                .required_unless_present_any(&[options::INPUT, options::ERROR]),
+                .required_unless_present_any([options::INPUT, options::ERROR]),
         )
         .arg(
             Arg::new(options::ERROR)
@@ -223,7 +223,7 @@ pub fn uu_app<'a>() -> Command<'a> {
                 .short(options::ERROR_SHORT)
                 .help("adjust standard error stream buffering")
                 .value_name("MODE")
-                .required_unless_present_any(&[options::INPUT, options::OUTPUT]),
+                .required_unless_present_any([options::INPUT, options::OUTPUT]),
         )
         .arg(
             Arg::new(options::COMMAND)

src/uu/tail/src/follow/files.rs

@@ -122,7 +122,7 @@ impl FileHandling {
         */
         self.get_mut(path)
             .reader
-            .replace(Box::new(BufReader::new(File::open(&path)?)));
+            .replace(Box::new(BufReader::new(File::open(path)?)));
         Ok(())
     }
 

src/uu/tail/src/tail.rs

@@ -155,7 +155,7 @@ fn tail_file(
         watcher_service.add_bad_path(path, input.display_name.as_str(), false)?;
     } else if input.is_tailable() {
         let metadata = path.metadata().ok();
-        match File::open(&path) {
+        match File::open(path) {
             Ok(mut file) => {
                 input_service.print_header(input);
                 let mut reader;

src/uu/unexpand/src/unexpand.rs

@@ -220,7 +220,7 @@ fn open(path: &str) -> BufReader<Box<dyn Read + 'static>> {
     if path == "-" {
         BufReader::new(Box::new(stdin()) as Box<dyn Read>)
     } else {
-        file_buf = match File::open(&path) {
+        file_buf = match File::open(path) {
             Ok(a) => a,
             Err(e) => crash!(1, "{}: {}", path.maybe_quote(), e),
         };

src/uu/uniq/src/uniq.rs

@@ -424,7 +424,7 @@ fn open_input_file(in_file_name: &str) -> UResult<BufReader<Box<dyn Read + 'stat
         Box::new(stdin()) as Box<dyn Read>
     } else {
         let path = Path::new(in_file_name);
-        let in_file = File::open(&path)
+        let in_file = File::open(path)
             .map_err_context(|| format!("Could not open {}", in_file_name.maybe_quote()))?;
         Box::new(in_file) as Box<dyn Read>
     };
@@ -436,7 +436,7 @@ fn open_output_file(out_file_name: &str) -> UResult<BufWriter<Box<dyn Write + 's
         Box::new(stdout()) as Box<dyn Write>
     } else {
         let path = Path::new(out_file_name);
-        let out_file = File::create(&path)
+        let out_file = File::create(path)
             .map_err_context(|| format!("Could not create {}", out_file_name.maybe_quote()))?;
         Box::new(out_file) as Box<dyn Write>
     };

src/uucore/src/lib/features/fs.rs

@@ -355,7 +355,7 @@ pub fn canonicalize<P: AsRef<Path>>(
                     followed_symlinks += 1;
                 } else {
                     let file_info =
-                        FileInformation::from_path(&result.parent().unwrap(), false).unwrap();
+                        FileInformation::from_path(result.parent().unwrap(), false).unwrap();
                     let mut path_to_follow = PathBuf::new();
                     for part in &parts {
                         path_to_follow.push(part.as_os_str());

tests/by-util/test_base64.rs

@@ -76,9 +76,10 @@ fn test_wrap() {
 #[test]
 fn test_wrap_no_arg() {
     for wrap_param in ["-w", "--wrap"] {
-        new_ucmd!().arg(wrap_param).fails().stderr_contains(
-            &"The argument '--wrap <wrap>' requires a value but none was supplied",
-        );
+        new_ucmd!()
+            .arg(wrap_param)
+            .fails()
+            .stderr_contains("The argument '--wrap <wrap>' requires a value but none was supplied");
     }
 }