fix a couply of clippy findings (#6007)

* clippy: autofix some lint warnings
* fix a couple more clippy warnings

build.rs

@@ -40,7 +40,7 @@ fn channel() -> String {
 
 fn commit_hash() -> Option<String> {
     Command::new("git")
-        .args(&["rev-parse", "--short", "HEAD"])
+        .args(["rev-parse", "--short", "HEAD"])
         .output()
         .ok()
         .and_then(|r| String::from_utf8(r.stdout).ok())
@@ -48,7 +48,7 @@ fn commit_hash() -> Option<String> {
 
 fn commit_date() -> Option<String> {
     Command::new("git")
-        .args(&["log", "-1", "--date=short", "--pretty=format:%cd"])
+        .args(["log", "-1", "--date=short", "--pretty=format:%cd"])
         .output()
         .ok()
         .and_then(|r| String::from_utf8(r.stdout).ok())

src/bin/main.rs

@@ -387,16 +387,11 @@ fn format_and_emit_report<T: Write>(session: &mut Session<'_, T>, input: Input)
 }
 
 fn should_print_with_colors<T: Write>(session: &mut Session<'_, T>) -> bool {
-    match term::stderr() {
-        Some(ref t)
-            if session.config.color().use_colored_tty()
+    term::stderr().is_some_and(|t| {
+        session.config.color().use_colored_tty()
             && t.supports_color()
-                && t.supports_attr(term::Attr::Bold) =>
-        {
-            true
-        }
-        _ => false,
-    }
+            && t.supports_attr(term::Attr::Bold)
+    })
 }
 
 fn print_usage_to_stdout(opts: &Options, reason: &str) {
@@ -445,7 +440,7 @@ fn print_version() {
 fn determine_operation(matches: &Matches) -> Result<Operation, OperationError> {
     if matches.opt_present("h") {
         let topic = matches.opt_str("h");
-        if topic == None {
+        if topic.is_none() {
             return Ok(Operation::Help(HelpOp::None));
         } else if topic == Some("config".to_owned()) {
             return Ok(Operation::Help(HelpOp::Config));

src/cargo-fmt/main.rs

@@ -507,7 +507,7 @@ fn run_rustfmt(
         let mut command = rustfmt_command()
             .stdout(stdout)
             .args(files)
-            .args(&["--edition", edition.as_str()])
+            .args(["--edition", edition.as_str()])
             .args(fmt_args)
             .spawn()
             .map_err(|e| match e.kind() {

src/cargo-fmt/test/mod.rs

@@ -20,7 +20,7 @@ fn default_options() {
 
 #[test]
 fn good_options() {
-    let o = Opts::parse_from(&[
+    let o = Opts::parse_from([
         "test",
         "-q",
         "-p",
@@ -48,7 +48,7 @@ fn good_options() {
 fn unexpected_option() {
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "unexpected"])
+            .try_get_matches_from(["test", "unexpected"])
             .is_err()
     );
 }
@@ -57,7 +57,7 @@ fn unexpected_option() {
 fn unexpected_flag() {
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "--flag"])
+            .try_get_matches_from(["test", "--flag"])
             .is_err()
     );
 }
@@ -66,19 +66,19 @@ fn unexpected_flag() {
 fn mandatory_separator() {
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "--emit"])
+            .try_get_matches_from(["test", "--emit"])
             .is_err()
     );
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "--", "--emit"])
+            .try_get_matches_from(["test", "--", "--emit"])
             .is_ok()
     );
 }
 
 #[test]
 fn multiple_packages_one_by_one() {
-    let o = Opts::parse_from(&[
+    let o = Opts::parse_from([
         "test",
         "-p",
         "package1",
@@ -92,7 +92,7 @@ fn multiple_packages_one_by_one() {
 
 #[test]
 fn multiple_packages_grouped() {
-    let o = Opts::parse_from(&[
+    let o = Opts::parse_from([
         "test",
         "--package",
         "package1",
@@ -108,7 +108,7 @@ fn multiple_packages_grouped() {
 fn empty_packages_1() {
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "-p"])
+            .try_get_matches_from(["test", "-p"])
             .is_err()
     );
 }
@@ -117,7 +117,7 @@ fn empty_packages_1() {
 fn empty_packages_2() {
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "-p", "--", "--check"])
+            .try_get_matches_from(["test", "-p", "--", "--check"])
             .is_err()
     );
 }
@@ -126,7 +126,7 @@ fn empty_packages_2() {
 fn empty_packages_3() {
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "-p", "--verbose"])
+            .try_get_matches_from(["test", "-p", "--verbose"])
             .is_err()
     );
 }
@@ -135,7 +135,7 @@ fn empty_packages_3() {
 fn empty_packages_4() {
     assert!(
         Opts::command()
-            .try_get_matches_from(&["test", "-p", "--check"])
+            .try_get_matches_from(["test", "-p", "--check"])
             .is_err()
     );
 }

src/comment.rs

@@ -503,7 +503,7 @@ fn new(line: &str) -> Option<ItemizedBlock> {
         let mut line_start = " ".repeat(indent);
 
         // Markdown blockquote start with a "> "
-        if line.trim_start().starts_with(">") {
+        if line.trim_start().starts_with('>') {
             // remove the original +2 indent because there might be multiple nested block quotes
             // and it's easier to reason about the final indent by just taking the length
             // of the new line_start. We update the indent because it effects the max width
@@ -654,7 +654,7 @@ fn join_block(s: &str, sep: &str) -> String {
         while let Some(line) = iter.next() {
             result.push_str(line);
             result.push_str(match iter.peek() {
-                Some(next_line) if next_line.is_empty() => sep.trim_end(),
+                Some(&"") => sep.trim_end(),
                 Some(..) => sep,
                 None => "",
             });
@@ -836,7 +836,7 @@ fn handle_line(
             }
         }
 
-        let is_markdown_header_doc_comment = is_doc_comment && line.starts_with("#");
+        let is_markdown_header_doc_comment = is_doc_comment && line.starts_with('#');
 
         // We only want to wrap the comment if:
         // 1) wrap_comments = true is configured
@@ -1761,7 +1761,7 @@ fn changed_comment_content(orig: &str, new: &str) -> bool {
     let code_comment_content = |code| {
         let slices = UngroupedCommentCodeSlices::new(code);
         slices
-            .filter(|&(ref kind, _, _)| *kind == CodeCharKind::Comment)
+            .filter(|(kind, _, _)| *kind == CodeCharKind::Comment)
             .flat_map(|(_, _, s)| CommentReducer::new(s))
     };
     let res = code_comment_content(orig).ne(code_comment_content(new));

src/emitter/checkstyle.rs

@@ -89,11 +89,11 @@ fn emits_empty_record_on_file_with_no_mismatches() {
     #[test]
     fn emits_single_xml_tree_containing_all_files() {
         let bin_file = "src/bin.rs";
-        let bin_original = vec!["fn main() {", "println!(\"Hello, world!\");", "}"];
-        let bin_formatted = vec!["fn main() {", "    println!(\"Hello, world!\");", "}"];
+        let bin_original = ["fn main() {", "println!(\"Hello, world!\");", "}"];
+        let bin_formatted = ["fn main() {", "    println!(\"Hello, world!\");", "}"];
         let lib_file = "src/lib.rs";
-        let lib_original = vec!["fn greet() {", "println!(\"Greetings!\");", "}"];
-        let lib_formatted = vec!["fn greet() {", "    println!(\"Greetings!\");", "}"];
+        let lib_original = ["fn greet() {", "println!(\"Greetings!\");", "}"];
+        let lib_formatted = ["fn greet() {", "    println!(\"Greetings!\");", "}"];
         let mut writer = Vec::new();
         let mut emitter = CheckstyleEmitter::default();
         let _ = emitter.emit_header(&mut writer);
@@ -118,7 +118,7 @@ fn emits_single_xml_tree_containing_all_files() {
             )
             .unwrap();
         let _ = emitter.emit_footer(&mut writer);
-        let exp_bin_xml = vec![
+        let exp_bin_xml = [
             format!(r#"<file name="{}">"#, bin_file),
             format!(
                 r#"<error line="2" severity="warning" message="Should be `{}`" />"#,
@@ -126,7 +126,7 @@ fn emits_single_xml_tree_containing_all_files() {
             ),
             String::from("</file>"),
         ];
-        let exp_lib_xml = vec![
+        let exp_lib_xml = [
             format!(r#"<file name="{}">"#, lib_file),
             format!(
                 r#"<error line="2" severity="warning" message="Should be `{}`" />"#,
@@ -136,7 +136,7 @@ fn emits_single_xml_tree_containing_all_files() {
         ];
         assert_eq!(
             String::from_utf8(writer).unwrap(),
-            vec![
+            [
                 r#"<?xml version="1.0" encoding="utf-8"?>"#,
                 "\n",
                 r#"<checkstyle version="4.3">"#,

src/emitter/json.rs

@@ -212,7 +212,7 @@ fn emits_empty_array_on_no_diffs() {
     #[test]
     fn emits_array_with_files_with_diffs() {
         let file_name = "src/bin.rs";
-        let original = vec![
+        let original = [
             "fn main() {",
             "println!(\"Hello, world!\");",
             "}",
@@ -225,7 +225,7 @@ fn emits_array_with_files_with_diffs() {
             "}",
             "}",
         ];
-        let formatted = vec![
+        let formatted = [
             "fn main() {",
             "    println!(\"Hello, world!\");",
             "}",
@@ -285,11 +285,11 @@ fn emits_array_with_files_with_diffs() {
     #[test]
     fn emits_valid_json_with_multiple_files() {
         let bin_file = "src/bin.rs";
-        let bin_original = vec!["fn main() {", "println!(\"Hello, world!\");", "}"];
-        let bin_formatted = vec!["fn main() {", "    println!(\"Hello, world!\");", "}"];
+        let bin_original = ["fn main() {", "println!(\"Hello, world!\");", "}"];
+        let bin_formatted = ["fn main() {", "    println!(\"Hello, world!\");", "}"];
         let lib_file = "src/lib.rs";
-        let lib_original = vec!["fn greet() {", "println!(\"Greetings!\");", "}"];
-        let lib_formatted = vec!["fn greet() {", "    println!(\"Greetings!\");", "}"];
+        let lib_original = ["fn greet() {", "println!(\"Greetings!\");", "}"];
+        let lib_formatted = ["fn greet() {", "    println!(\"Greetings!\");", "}"];
         let mut writer = Vec::new();
         let mut emitter = JsonEmitter::default();
         let _ = emitter.emit_header(&mut writer);

src/format-diff/main.rs

@@ -234,14 +234,14 @@ mod cmd_line_tests {
     #[test]
     fn default_options() {
         let empty: Vec<String> = vec![];
-        let o = Opts::parse_from(&empty);
+        let o = Opts::parse_from(empty);
         assert_eq!(DEFAULT_PATTERN, o.filter);
         assert_eq!(0, o.skip_prefix);
     }
 
     #[test]
     fn good_options() {
-        let o = Opts::parse_from(&["test", "-p", "10", "-f", r".*\.hs"]);
+        let o = Opts::parse_from(["test", "-p", "10", "-f", r".*\.hs"]);
         assert_eq!(r".*\.hs", o.filter);
         assert_eq!(10, o.skip_prefix);
     }
@@ -250,7 +250,7 @@ fn good_options() {
     fn unexpected_option() {
         assert!(
             Opts::command()
-                .try_get_matches_from(&["test", "unexpected"])
+                .try_get_matches_from(["test", "unexpected"])
                 .is_err()
         );
     }
@@ -259,7 +259,7 @@ fn unexpected_option() {
     fn unexpected_flag() {
         assert!(
             Opts::command()
-                .try_get_matches_from(&["test", "--flag"])
+                .try_get_matches_from(["test", "--flag"])
                 .is_err()
         );
     }
@@ -268,7 +268,7 @@ fn unexpected_flag() {
     fn overridden_option() {
         assert!(
             Opts::command()
-                .try_get_matches_from(&["test", "-p", "10", "-p", "20"])
+                .try_get_matches_from(["test", "-p", "10", "-p", "20"])
                 .is_err()
         );
     }
@@ -277,7 +277,7 @@ fn overridden_option() {
     fn negative_filter() {
         assert!(
             Opts::command()
-                .try_get_matches_from(&["test", "-p", "-1"])
+                .try_get_matches_from(["test", "-p", "-1"])
                 .is_err()
         );
     }

src/lib.rs

@@ -257,8 +257,8 @@ fn warning_count(&self) -> usize {
         self.internal
             .borrow()
             .0
-            .iter()
-            .map(|(_, errors)| errors.len())
+            .values()
+            .map(|errors| errors.len())
             .sum()
     }
 

src/macros.rs

@@ -389,7 +389,7 @@ fn rewrite_empty_macro_def_body(
         stmts: vec![].into(),
         id: rustc_ast::node_id::DUMMY_NODE_ID,
         rules: ast::BlockCheckMode::Default,
-        span: span,
+        span,
         tokens: None,
         could_be_bare_literal: false,
     };

src/source_file.rs

@@ -33,7 +33,7 @@ pub(crate) fn write_all_files<T>(
     let mut emitter = create_emitter(config);
 
     emitter.emit_header(out)?;
-    for &(ref filename, ref text) in source_file {
+    for (filename, text) in source_file {
         write_file(
             None,
             filename,

src/test/mod.rs

@@ -332,7 +332,7 @@ fn assert_stdin_output(
         let mut session = Session::new(config, Some(&mut buf));
         session.format(input).unwrap();
         let errors = ReportedErrors {
-            has_diff: has_diff,
+            has_diff,
             ..Default::default()
         };
         assert_eq!(session.errors, errors);