Fix some clippy warnings

src/uu/cksum/src/cksum.rs

@@ -147,7 +147,7 @@ fn cksum(fname: &str) -> io::Result<(u32, usize)> {
                     "Is a directory",
                 ));
             };
-            if !path.metadata().is_ok() {
+            if path.metadata().is_err() {
                 return Err(std::io::Error::new(
                     io::ErrorKind::NotFound,
                     "No such file or directory",

src/uu/fmt/src/linebreak.rs

@@ -81,7 +81,7 @@ pub fn break_lines(para: &Paragraph, opts: &FmtOptions, ostream: &mut BufWriter<
     let mut break_args = BreakArgs {
         opts,
         init_len: p_init_len,
-        indent_str: &p_indent[..],
+        indent_str: p_indent,
         indent_len: p_indent_len,
         uniform,
         ostream,

src/uu/ln/src/ln.rs

@@ -223,7 +223,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     } else if matches.is_present(OPT_BACKUP) {
         match matches.value_of(OPT_BACKUP) {
             None => BackupMode::ExistingBackup,
-            Some(mode) => match &mode[..] {
+            Some(mode) => match mode {
                 "simple" | "never" => BackupMode::SimpleBackup,
                 "numbered" | "t" => BackupMode::NumberedBackup,
                 "existing" | "nil" => BackupMode::ExistingBackup,

src/uu/ls/src/ls.rs

@@ -270,11 +270,9 @@ impl Config {
             .any(|i| i >= idx)
             {
                 format = Format::Long;
-            } else {
-                if let Some(mut indices) = options.indices_of(options::format::ONELINE) {
-                    if indices.any(|i| i > idx) {
-                        format = Format::OneLine;
-                    }
+            } else if let Some(mut indices) = options.indices_of(options::format::ONELINE) {
+                if indices.any(|i| i > idx) {
+                    format = Format::OneLine;
                 }
             }
         }

src/uu/nl/src/helper.rs

@@ -37,7 +37,7 @@ pub fn parse_options(settings: &mut crate::Settings, opts: &clap::ArgMatches) ->
     }
     match opts.value_of(options::NUMBER_FORMAT) {
         None => {}
-        Some(val) => match val.as_ref() {
+        Some(val) => match val {
             "ln" => {
                 settings.number_format = crate::NumberFormat::Left;
             }

src/uu/printf/src/tokenize/num_format/formatters/cninetyninehexfloatf.rs

@@ -59,7 +59,7 @@ fn get_primitive_hex(
     // assign 0
     let (mut first_segment_raw, second_segment_raw) = match analysis.decimal_pos {
         Some(pos) => (&str_in[..pos], &str_in[pos + 1..]),
-        None => (&str_in[..], "0"),
+        None => (str_in, "0"),
     };
     if first_segment_raw.is_empty() {
         first_segment_raw = "0";

src/uu/printf/src/tokenize/num_format/formatters/float_common.rs

@@ -218,7 +218,7 @@ pub fn get_primitive_dec(
     // assign 0
     let (mut first_segment_raw, second_segment_raw) = match analysis.decimal_pos {
         Some(pos) => (&str_in[..pos], &str_in[pos + 1..]),
-        None => (&str_in[..], "0"),
+        None => (str_in, "0"),
     };
     if first_segment_raw.is_empty() {
         first_segment_raw = "0";

src/uu/shred/src/shred.rs

@@ -338,7 +338,7 @@ this is the default for non-regular files",
         Some(s) => match s.parse::<usize>() {
             Ok(u) => u,
             Err(_) => {
-                errs.push(String::from(format!("invalid number of passes: '{}'", s)));
+                errs.push(format!("invalid number of passes: '{}'", s));
                 0
             }
         },

tests/common/util.rs

@@ -1,8 +1,11 @@
 #![allow(dead_code)]
 
+#[cfg(not(windows))]
 use libc;
 use std::env;
-use std::ffi::{CString, OsStr};
+#[cfg(not(windows))]
+use std::ffi::CString;
+use std::ffi::OsStr;
 use std::fs::{self, File, OpenOptions};
 use std::io::{Read, Result, Write};
 #[cfg(unix)]