diff --git a/Cargo.lock b/Cargo.lock
index 769e019faf1..bb765584d8f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -130,7 +130,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "cargo_metadata"
-version = "0.8.2"
+version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -263,7 +263,7 @@ dependencies = [
 
 [[package]]
 name = "env_logger"
-version = "0.6.2"
+version = "0.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -800,10 +800,10 @@ dependencies = [
  "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "anyhow 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "bytecount 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cargo_metadata 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cargo_metadata 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "diff 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "dirs 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.21 (registry+https://github.com/rust-lang/crates.io-index)",
  "ignore 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1122,7 +1122,7 @@ dependencies = [
 "checksum bstr 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8d6c2c5b58ab920a4f5aeaaca34b4488074e8cc7596af94e6f8c6ff247c60245"
 "checksum bytecount 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b0017894339f586ccb943b01b9555de56770c11cda818e7e3d8bd93f4ed7f46e"
 "checksum byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a7c3dd8985a7111efc5c80b44e23ecdd8c007de8ade3b96595387e812b957cf5"
-"checksum cargo_metadata 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "700b3731fd7d357223d0000f4dbf1808401b694609035c3c411fbc0cd375c426"
+"checksum cargo_metadata 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "46e3374c604fb39d1a2f35ed5e4a4e30e60d01fab49446e08f1b3e9a90aef202"
 "checksum cc 1.0.46 (registry+https://github.com/rust-lang/crates.io-index)" = "0213d356d3c4ea2c18c40b037c3be23cd639825c18f25ee670ac7813beeef99c"
 "checksum cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)" = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 "checksum clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5067f5bb2d80ef5d68b4c87db81601f0b75bca627bc2ef76b141d7b846a3c6d9"
@@ -1138,7 +1138,7 @@ dependencies = [
 "checksum dirs-sys 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "afa0b23de8fd801745c471deffa6e12d248f962c9fd4b4c33787b055599bde7b"
 "checksum either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
 "checksum ena 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8944dc8fa28ce4a38f778bd46bf7d923fe73eed5a439398507246c8e017e6f36"
-"checksum env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "aafcde04e90a5226a6443b7aabdb016ba2f8307c847d524724bd9b346dd1a2d3"
+"checksum env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
 "checksum failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "f8273f13c977665c5db7eb2b99ae520952fe5ac831ae4cd09d80c4c7042b5ed9"
 "checksum failure_derive 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0bc225b78e0391e4b8683440bf2e63c2deeeb2ce5189eab46e2b68c6d3725d08"
 "checksum fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "2fad85553e09a6f881f739c29f0b00b0f01357c743266d478b68951ce23285f3"
diff --git a/Cargo.toml b/Cargo.toml
index c654ebf36c6..a914f956cfe 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -43,9 +43,9 @@ regex = "1.0"
 term = "0.6"
 diff = "0.1"
 log = "0.4"
-env_logger = "0.6"
+env_logger = "0.7"
 getopts = "0.2"
-cargo_metadata = "0.8"
+cargo_metadata = "0.9"
 bytecount = "0.6"
 unicode-width = "0.1.5"
 unicode_categories = "0.1.1"
diff --git a/config_proc_macro/src/item_enum.rs b/config_proc_macro/src/item_enum.rs
index dcee77a8549..6101e65d6e9 100644
--- a/config_proc_macro/src/item_enum.rs
+++ b/config_proc_macro/src/item_enum.rs
@@ -123,11 +123,11 @@ fn impl_from_str(ident: &syn::Ident, variants: &Variants) -> TokenStream {
 }
 
 fn doc_hint_of_variant(variant: &syn::Variant) -> String {
-    find_doc_hint(&variant.attrs).unwrap_or(variant.ident.to_string())
+    find_doc_hint(&variant.attrs).unwrap_or_else(|| variant.ident.to_string())
 }
 
 fn config_value_of_variant(variant: &syn::Variant) -> String {
-    find_config_value(&variant.attrs).unwrap_or(variant.ident.to_string())
+    find_config_value(&variant.attrs).unwrap_or_else(|| variant.ident.to_string())
 }
 
 fn impl_serde(ident: &syn::Ident, variants: &Variants) -> TokenStream {
diff --git a/src/bin/main.rs b/src/bin/main.rs
index 0335dc99116..b277b9323f1 100644
--- a/src/bin/main.rs
+++ b/src/bin/main.rs
@@ -235,7 +235,7 @@ fn execute(opts: &Options) -> Result<i32> {
             let file = PathBuf::from(path);
             let file = file.canonicalize().unwrap_or(file);
 
-            let (config, _) = load_config(Some(file.parent().unwrap()), Some(options.clone()))?;
+            let (config, _) = load_config(Some(file.parent().unwrap()), Some(options))?;
             let toml = config.all_options().to_toml()?;
             io::stdout().write_all(toml.as_bytes())?;
 
@@ -590,7 +590,7 @@ impl GetOptsOptions {
         options.inline_config = matches
             .opt_strs("config")
             .iter()
-            .flat_map(|config| config.split(","))
+            .flat_map(|config| config.split(','))
             .map(
                 |key_val| match key_val.char_indices().find(|(_, ch)| *ch == '=') {
                     Some((middle, _)) => {
diff --git a/src/cargo-fmt/main.rs b/src/cargo-fmt/main.rs
index 7c7e600b7d8..f2a345a9610 100644
--- a/src/cargo-fmt/main.rs
+++ b/src/cargo-fmt/main.rs
@@ -102,11 +102,11 @@ fn execute() -> i32 {
     if opts.version {
         return handle_command_status(get_rustfmt_info(&[String::from("--version")]));
     }
-    if opts.rustfmt_options.iter().any(|s| {
-        ["--print-config", "-h", "--help", "-V", "--version"].contains(&s.as_str())
-            || s.starts_with("--help=")
-            || s.starts_with("--print-config=")
-    }) {
+    if opts
+        .rustfmt_options
+        .iter()
+        .any(|s| is_status_options(s.as_str()))
+    {
         return handle_command_status(get_rustfmt_info(&opts.rustfmt_options));
     }
 
@@ -142,6 +142,12 @@ fn execute() -> i32 {
     }
 }
 
+fn is_status_options(s: &str) -> bool {
+    ["--print-config", "-h", "--help", "-V", "--version"].contains(&s)
+        || s.starts_with("--help=")
+        || s.starts_with("--print-config=")
+}
+
 fn build_rustfmt_args(opts: &Opts, rustfmt_args: &mut Vec<String>) -> Result<(), String> {
     let mut contains_check = false;
     let mut contains_emit_mode = false;
@@ -285,9 +291,9 @@ impl Target {
     ) -> Self {
         let path = PathBuf::from(&target.src_path);
         let canonicalized = fs::canonicalize(&path).unwrap_or(path);
-        let test_files = nested_int_test_files.unwrap_or(vec![]);
+        let test_files = nested_int_test_files.unwrap_or_else(Vec::new);
 
-        Target {
+        Self {
             path: canonicalized,
             kind: target.kind[0].clone(),
             edition: target.edition.clone(),
@@ -417,7 +423,7 @@ fn get_targets_root_only(
                 .map(|p| p.targets)
                 .flatten()
                 .collect(),
-            PathBuf::from(current_dir_manifest),
+            current_dir_manifest,
         ),
     };
 
@@ -660,7 +666,7 @@ fn get_cargo_metadata(
     match cmd.exec() {
         Ok(metadata) => Ok(metadata),
         Err(_) => {
-            cmd.other_options(vec![]);
+            cmd.other_options(&[]);
             match cmd.exec() {
                 Ok(metadata) => Ok(metadata),
                 Err(error) => Err(io::Error::new(io::ErrorKind::Other, error.to_string())),
diff --git a/src/config/config_type.rs b/src/config/config_type.rs
index 618de16bc15..a3d31610bc7 100644
--- a/src/config/config_type.rs
+++ b/src/config/config_type.rs
@@ -139,7 +139,7 @@ macro_rules! create_config {
                 ConfigWasSet(self)
             }
 
-            fn fill_from_parsed_config(mut self, parsed: PartialConfig, dir: &Path) -> Config {
+            fn fill_from_parsed_config(mut self, parsed: PartialConfig, dir: &Path) -> Self {
                 let deprecate_skip_children = || {
                     let msg = "Option skip_children is deprecated since it is now the default to \
                                not format submodules of given files (#3587)";
@@ -248,8 +248,10 @@ macro_rules! create_config {
 
             #[allow(unreachable_pub)]
             pub fn is_hidden_option(name: &str) -> bool {
-                const HIDE_OPTIONS: [&str; 6] =
-                    ["verbose", "verbose_diff", "file_lines", "width_heuristics", "recursive", "print_misformatted_file_names"];
+                const HIDE_OPTIONS: [&str; 6] = [
+                    "verbose", "verbose_diff", "file_lines", "width_heuristics",
+                    "recursive", "print_misformatted_file_names",
+                ];
                 HIDE_OPTIONS.contains(&name)
             }
 
@@ -271,7 +273,7 @@ macro_rules! create_config {
                             }
                             name_out.push_str(name_raw);
                             name_out.push(' ');
-                            let mut default_str = format!("{}", $def);
+                            let mut default_str = $def.to_string();
                             if default_str.is_empty() {
                                 default_str = String::from("\"\"");
                             }
@@ -322,19 +324,19 @@ macro_rules! create_config {
             #[allow(unreachable_pub)]
             /// Returns `true` if the config key was explicitly set and is the default value.
             pub fn is_default(&self, key: &str) -> bool {
-                $(
-                    if let stringify!($i) = key {
-                        return self.$i.1 && self.$i.2 == $def;
-                    }
-                 )+
-                false
+                match key {
+                    $(
+                        stringify!($i) => self.$i.1 && self.$i.2 == $def,
+                    )+
+                    _ => false,
+                }
             }
         }
 
         // Template for the default configuration
         impl Default for Config {
-            fn default() -> Config {
-                Config {
+            fn default() -> Self {
+                Self {
                     license_template: None,
                     $(
                         $i: (Cell::new(false), false, $def, $stb),
diff --git a/src/config/mod.rs b/src/config/mod.rs
index 621caa72aee..b0c99c049e3 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -513,7 +513,9 @@ mod test {
             Ok(_) => panic!("Expected configuration error"),
             Err(msg) => assert_eq!(
                 msg,
-                "Error: Conflicting config options `skip_children` and `recursive` are both enabled. `skip_children` has been deprecated and should be removed from your config.",
+                "Error: Conflicting config options `skip_children` and `recursive` \
+                are both enabled. `skip_children` has been deprecated and should be \
+                removed from your config.",
             ),
         }
     }
diff --git a/src/emitter/json.rs b/src/emitter/json.rs
index 7c0f862cbc6..9cf37bf1289 100644
--- a/src/emitter/json.rs
+++ b/src/emitter/json.rs
@@ -136,7 +136,7 @@ mod tests {
             ],
         };
 
-        let _ = emitter
+        emitter
             .add_misformatted_file(&FileName::Real(PathBuf::from(file)), vec![mismatch])
             .unwrap();
 
@@ -181,7 +181,7 @@ mod tests {
             ],
         };
 
-        let _ = emitter
+        emitter
             .add_misformatted_file(&FileName::Real(PathBuf::from(file)), vec![mismatch])
             .unwrap();
 
@@ -206,7 +206,7 @@ mod tests {
             .unwrap();
         let _ = emitter.emit_footer(&mut writer);
         assert_eq!(result.has_diff, false);
-        assert_eq!(&writer[..], "[]\n".as_bytes());
+        assert_eq!(&writer[..], b"[]\n");
     }
 
     #[test]
diff --git a/src/expr.rs b/src/expr.rs
index 181a1a61552..4f74372d521 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -600,7 +600,7 @@ pub(crate) fn rewrite_cond(
                 String::from("\n") + &shape.indent.block_only().to_string(context.config);
             control_flow
                 .rewrite_cond(context, shape, &alt_block_sep)
-                .and_then(|rw| Some(rw.0))
+                .map(|rw| rw.0)
         }),
     }
 }
@@ -835,7 +835,7 @@ impl<'a> ControlFlow<'a> {
                 rewrite_missing_comment(mk_sp(comments_lo, expr.span.lo()), cond_shape, context)
             {
                 if !self.connector.is_empty() && !comment.is_empty() {
-                    if comment_style(&comment, false).is_line_comment() || comment.contains("\n") {
+                    if comment_style(&comment, false).is_line_comment() || comment.contains('\n') {
                         let newline = &pat_shape
                             .indent
                             .block_indent(context.config)
diff --git a/src/formatting.rs b/src/formatting.rs
index eb4f37d1ab2..da92992559e 100644
--- a/src/formatting.rs
+++ b/src/formatting.rs
@@ -91,7 +91,7 @@ fn format_project<T: FormatHandler>(
     let files = modules::ModResolver::new(
         &context.parse_session,
         directory_ownership.unwrap_or(DirectoryOwnership::UnownedViaMod(true)),
-        !(input_is_stdin || !config.recursive()),
+        !input_is_stdin && config.recursive(),
     )
     .visit_crate(&krate)
     .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
diff --git a/src/formatting/newline_style.rs b/src/formatting/newline_style.rs
index ac620094900..97c4fc16d6f 100644
--- a/src/formatting/newline_style.rs
+++ b/src/formatting/newline_style.rs
@@ -77,7 +77,7 @@ fn convert_to_windows_newlines(formatted_text: &String) -> String {
     transformed
 }
 
-fn convert_to_unix_newlines(formatted_text: &String) -> String {
+fn convert_to_unix_newlines(formatted_text: &str) -> String {
     formatted_text.replace(WINDOWS_NEWLINE, UNIX_NEWLINE)
 }
 
diff --git a/src/items.rs b/src/items.rs
index 1ecbdbceb9e..161997f969c 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -1210,7 +1210,7 @@ impl<'a> Rewrite for TraitAliasBounds<'a> {
 
         let fits_single_line = !generic_bounds_str.contains('\n')
             && !where_str.contains('\n')
-            && generic_bounds_str.len() + where_str.len() + 1 <= shape.width;
+            && generic_bounds_str.len() + where_str.len() < shape.width;
         let space = if generic_bounds_str.is_empty() || where_str.is_empty() {
             Cow::from("")
         } else if fits_single_line {
@@ -1998,7 +1998,7 @@ impl Rewrite for ast::Param {
             let num_attrs = self.attrs.len();
             (
                 mk_sp(self.attrs[num_attrs - 1].span.hi(), self.pat.span.lo()),
-                param_attrs_result.contains("\n"),
+                param_attrs_result.contains('\n'),
             )
         } else {
             (mk_sp(self.span.lo(), self.span.lo()), false)
diff --git a/src/lists.rs b/src/lists.rs
index 77c076540f1..8f98ab0747f 100644
--- a/src/lists.rs
+++ b/src/lists.rs
@@ -823,7 +823,7 @@ where
 pub(crate) fn total_item_width(item: &ListItem) -> usize {
     comment_len(item.pre_comment.as_ref().map(|x| &(*x)[..]))
         + comment_len(item.post_comment.as_ref().map(|x| &(*x)[..]))
-        + &item.item.as_ref().map_or(0, |s| unicode_str_width(&s))
+        + item.item.as_ref().map_or(0, |s| unicode_str_width(&s))
 }
 
 fn comment_len(comment: Option<&str>) -> usize {
diff --git a/src/macros.rs b/src/macros.rs
index 5d27b485e1d..4fa62982e9f 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -225,18 +225,17 @@ pub(crate) fn rewrite_macro(
 }
 
 fn check_keyword<'a, 'b: 'a>(parser: &'a mut Parser<'b>) -> Option<MacroArg> {
+    let is_delim = |kind| match kind {
+        TokenKind::Eof | TokenKind::Comma | TokenKind::CloseDelim(DelimToken::NoDelim) => true,
+        _ => false,
+    };
     for &keyword in RUST_KW.iter() {
-        if parser.token.is_keyword(keyword)
-            && parser.look_ahead(1, |t| {
-                t.kind == TokenKind::Eof
-                    || t.kind == TokenKind::Comma
-                    || t.kind == TokenKind::CloseDelim(DelimToken::NoDelim)
-            })
-        {
+        if parser.token.is_keyword(keyword) && parser.look_ahead(1, |t| is_delim(t.kind.clone())) {
             parser.bump();
-            let macro_arg =
-                MacroArg::Keyword(ast::Ident::with_dummy_span(keyword), parser.prev_span);
-            return Some(macro_arg);
+            return Some(MacroArg::Keyword(
+                ast::Ident::with_dummy_span(keyword),
+                parser.prev_span,
+            ));
         }
     }
     None
diff --git a/src/modules.rs b/src/modules.rs
index 0c35cc2d073..bef70cde80e 100644
--- a/src/modules.rs
+++ b/src/modules.rs
@@ -67,7 +67,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
     ) -> Result<FileModMap<'ast>, String> {
         let root_filename = self.parse_sess.span_to_filename(krate.span);
         self.directory.path = match root_filename {
-            FileName::Real(ref p) => p.parent().unwrap_or(Path::new("")).to_path_buf(),
+            FileName::Real(ref p) => p.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
             _ => PathBuf::new(),
         };
 
diff --git a/src/skip.rs b/src/skip.rs
index 6b4e04a7173..e21d407720d 100644
--- a/src/skip.rs
+++ b/src/skip.rs
@@ -1,6 +1,13 @@
 //! Module that contains skip related stuffs.
 
-use syntax::ast;
+use syntax::ast::{Attribute, PathSegment};
+use syntax::symbol::{sym, Symbol};
+
+macro_rules! sym {
+    ($tt:tt) => {
+        Symbol::intern(stringify!($tt))
+    };
+}
 
 /// Take care of skip name stack. You can update it by attributes slice or
 /// by other context. Query this context to know if you need skip a block.
@@ -11,13 +18,26 @@ pub(crate) struct SkipContext {
 }
 
 impl SkipContext {
-    pub(crate) fn update_with_attrs(&mut self, attrs: &[ast::Attribute]) {
-        self.macros.append(&mut get_skip_names("macros", attrs));
-        self.attributes
-            .append(&mut get_skip_names("attributes", attrs));
+    pub(crate) fn update_with_attrs(&mut self, attrs: &[Attribute]) {
+        fn get_skip_names(vs: &mut Vec<String>, attr: &Attribute) {
+            if let Some(list) = attr.meta_item_list() {
+                for nested_meta_item in list {
+                    if let Some(name) = nested_meta_item.ident() {
+                        vs.push(name.to_string());
+                    }
+                }
+            }
+        }
+        for attr in attrs {
+            if is_skip_attr_with(&attr.item.path.segments, |s| s == sym!(macros)) {
+                get_skip_names(&mut self.macros, attr)
+            } else if is_skip_attr_with(&attr.item.path.segments, |s| s == sym::attributes) {
+                get_skip_names(&mut self.attributes, attr)
+            }
+        }
     }
 
-    pub(crate) fn update(&mut self, mut other: SkipContext) {
+    pub(crate) fn update(&mut self, mut other: Self) {
         self.macros.append(&mut other.macros);
         self.attributes.append(&mut other.attributes);
     }
@@ -31,43 +51,18 @@ impl SkipContext {
     }
 }
 
-static RUSTFMT: &'static str = "rustfmt";
-static SKIP: &'static str = "skip";
-
 /// Say if you're playing with `rustfmt`'s skip attribute
-pub(crate) fn is_skip_attr(segments: &[ast::PathSegment]) -> bool {
-    if segments.len() < 2 || segments[0].ident.to_string() != RUSTFMT {
+pub(crate) fn is_skip_attr(segments: &[PathSegment]) -> bool {
+    is_skip_attr_with(segments, |s| s == sym!(macros) || s == sym::attributes)
+}
+
+fn is_skip_attr_with(segments: &[PathSegment], pred: impl FnOnce(Symbol) -> bool) -> bool {
+    if segments.len() < 2 || segments[0].ident.name != sym::rustfmt {
         return false;
     }
     match segments.len() {
-        2 => segments[1].ident.to_string() == SKIP,
-        3 => {
-            segments[1].ident.to_string() == SKIP
-                && ["macros", "attributes"]
-                    .iter()
-                    .any(|&n| n == &segments[2].ident.name.as_str())
-        }
+        2 => segments[1].ident.name == sym!(skip),
+        3 => segments[1].ident.name == sym!(skip) && pred(segments[2].ident.name),
         _ => false,
     }
 }
-
-fn get_skip_names(kind: &str, attrs: &[ast::Attribute]) -> Vec<String> {
-    let mut skip_names = vec![];
-    let path = format!("{}::{}::{}", RUSTFMT, SKIP, kind);
-    for attr in attrs {
-        // syntax::ast::Path is implemented partialEq
-        // but it is designed for segments.len() == 1
-        if format!("{}", attr.path) != path {
-            continue;
-        }
-
-        if let Some(list) = attr.meta_item_list() {
-            for nested_meta_item in list {
-                if let Some(name) = nested_meta_item.ident() {
-                    skip_names.push(name.to_string());
-                }
-            }
-        }
-    }
-    skip_names
-}
diff --git a/src/syntux/parser.rs b/src/syntux/parser.rs
index b4da22f23ae..ad38537d8d1 100644
--- a/src/syntux/parser.rs
+++ b/src/syntux/parser.rs
@@ -26,7 +26,7 @@ impl<'a> Directory {
     fn to_syntax_directory(&'a self) -> syntax::parse::Directory<'a> {
         syntax::parse::Directory {
             path: Cow::Borrowed(&self.path),
-            ownership: self.ownership.clone(),
+            ownership: self.ownership,
         }
     }
 }
@@ -86,7 +86,6 @@ impl<'a> ParserBuilder<'a> {
         parser.cfg_mods = false;
         parser.recurse_into_file_modules = config.recursive();
 
-
         Ok(Parser { parser, sess })
     }
 
@@ -209,7 +208,7 @@ impl<'a> Parser<'a> {
             }
 
             match Parser::parse_mod_items(&mut parser, lo) {
-                Ok(m) => Some(m.clone()),
+                Ok(m) => Some(m),
                 Err(mut db) => {
                     db.cancel();
                     sess.reset_errors();
diff --git a/src/syntux/session.rs b/src/syntux/session.rs
index b1ae5e04871..5d96d516783 100644
--- a/src/syntux/session.rs
+++ b/src/syntux/session.rs
@@ -173,15 +173,13 @@ impl ParseSess {
     pub(crate) fn span_to_first_line_string(&self, span: Span) -> String {
         let file_lines = self.parse_sess.source_map().span_to_lines(span).ok();
 
-        let first_line_str = match file_lines {
+        match file_lines {
             Some(fl) => fl
                 .file
                 .get_line(fl.lines[0].line_index)
-                .map(|s| s.into_owned()),
-            None => return String::new(),
-        };
-
-        first_line_str.unwrap_or(String::new())
+                .map_or_else(String::new, |s| s.to_string()),
+            None => String::new(),
+        }
     }
 
     pub(crate) fn line_of_byte_pos(&self, pos: BytePos) -> usize {
@@ -292,7 +290,7 @@ mod tests {
                 message: vec![],
                 children: vec![],
                 suggestions: vec![],
-                span: span.unwrap_or_else(|| MultiSpan::new()),
+                span: span.unwrap_or_else(MultiSpan::new),
             }
         }
 
@@ -305,12 +303,8 @@ mod tests {
             let emitter_writer = TestEmitter { num_emitted_errors };
             let source_map =
                 source_map.unwrap_or_else(|| Rc::new(SourceMap::new(FilePathMapping::empty())));
-            let ignore_path_set = Rc::new(
-                IgnorePathSet::from_ignore_list(
-                    &ignore_list.unwrap_or_else(|| IgnoreList::default()),
-                )
-                .unwrap(),
-            );
+            let ignore_path_set =
+                Rc::new(IgnorePathSet::from_ignore_list(&ignore_list.unwrap_or_default()).unwrap());
             SilentOnIgnoredFilesEmitter {
                 has_non_ignorable_parser_errors: false,
                 source_map,
diff --git a/src/test/mod.rs b/src/test/mod.rs
index a208b1d75b6..ab156e39175 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -101,10 +101,9 @@ fn is_file_skip(path: &Path) -> bool {
 fn get_test_files(path: &Path, recursive: bool) -> Vec<PathBuf> {
     let mut files = vec![];
     if path.is_dir() {
-        for entry in fs::read_dir(path).expect(&format!(
-            "couldn't read directory {}",
-            path.to_str().unwrap()
-        )) {
+        for entry in fs::read_dir(path)
+            .unwrap_or_else(|_| panic!("couldn't read directory {}", path.display()))
+        {
             let entry = entry.expect("couldn't get `DirEntry`");
             let path = entry.path();
             if path.is_dir() && recursive {
@@ -118,10 +117,9 @@ fn get_test_files(path: &Path, recursive: bool) -> Vec<PathBuf> {
 }
 
 fn verify_config_used(path: &Path, config_name: &str) {
-    for entry in fs::read_dir(path).expect(&format!(
-        "couldn't read {} directory",
-        path.to_str().unwrap()
-    )) {
+    for entry in
+        fs::read_dir(path).unwrap_or_else(|_| panic!("couldn't read {} directory", path.display()))
+    {
         let entry = entry.expect("couldn't get directory entry");
         let path = entry.path();
         if path.extension().map_or(false, |f| f == "rs") {
@@ -435,9 +433,9 @@ fn stdin_formatting_smoke_test() {
     }
 
     #[cfg(not(windows))]
-    assert_eq!(buf, "stdin:\n\nfn main() {}\n".as_bytes());
+    assert_eq!(buf, b"stdin:\n\nfn main() {}\n");
     #[cfg(windows)]
-    assert_eq!(buf, "stdin:\n\nfn main() {}\r\n".as_bytes());
+    assert_eq!(buf, b"stdin:\n\nfn main() {}\r\n");
 }
 
 #[test]
@@ -459,7 +457,7 @@ fn stdin_parser_panic_caught() {
 fn stdin_works_with_modified_lines() {
     init_log();
     let input = "\nfn\n some( )\n{\n}\nfn main () {}\n";
-    let output = "1 6 2\nfn some() {}\nfn main() {}\n";
+    let output = b"1 6 2\nfn some() {}\nfn main() {}\n";
 
     let input = Input::Text(input.to_owned());
     let mut config = Config::default();
@@ -475,7 +473,7 @@ fn stdin_works_with_modified_lines() {
         };
         assert_eq!(session.errors, errors);
     }
-    assert_eq!(buf, output.as_bytes());
+    assert_eq!(buf, output);
 }
 
 /// Ensures that `EmitMode::Json` works with input from `stdin`.
@@ -510,8 +508,8 @@ fn stdin_disable_all_formatting_test() {
         // These tests require nightly.
         _ => return,
     }
-    let input = String::from("fn main() { println!(\"This should not be formatted.\"); }");
-    let mut child = Command::new(rustfmt().to_str().unwrap())
+    let input = "fn main() { println!(\"This should not be formatted.\"); }";
+    let mut child = Command::new(rustfmt())
         .stdin(Stdio::piped())
         .stdout(Stdio::piped())
         .arg("--config-path=./tests/config/disable_all_formatting.toml")
@@ -890,9 +888,8 @@ fn make_temp_file(file_name: &'static str) -> TempFile {
     let path = Path::new(&target_dir).join(file_name);
 
     let mut file = File::create(&path).expect("couldn't create temp file");
-    let content = "fn main() {}\n";
-    file.write_all(content.as_bytes())
-        .expect("couldn't write temp file");
+    let content = b"fn main() {}\n";
+    file.write_all(content).expect("couldn't write temp file");
     TempFile { path }
 }
 
@@ -903,29 +900,34 @@ impl Drop for TempFile {
     }
 }
 
-fn rustfmt() -> PathBuf {
-    let mut me = env::current_exe().expect("failed to get current executable");
-    // Chop of the test name.
-    me.pop();
-    // Chop off `deps`.
-    me.pop();
+fn rustfmt() -> &'static Path {
+    lazy_static! {
+        static ref RUSTFMT_PATH: PathBuf = {
+            let mut me = env::current_exe().expect("failed to get current executable");
+            // Chop of the test name.
+            me.pop();
+            // Chop off `deps`.
+            me.pop();
 
-    // If we run `cargo test --release`, we might only have a release build.
-    if cfg!(release) {
-        // `../release/`
-        me.pop();
-        me.push("release");
+            // If we run `cargo test --release`, we might only have a release build.
+            if cfg!(release) {
+                // `../release/`
+                me.pop();
+                me.push("release");
+            }
+            me.push("rustfmt");
+            assert!(
+                me.is_file() || me.with_extension("exe").is_file(),
+                if cfg!(release) {
+                    "no rustfmt bin, try running `cargo build --release` before testing"
+                } else {
+                    "no rustfmt bin, try running `cargo build` before testing"
+                }
+            );
+            me
+        };
     }
-    me.push("rustfmt");
-    assert!(
-        me.is_file() || me.with_extension("exe").is_file(),
-        if cfg!(release) {
-            "no rustfmt bin, try running `cargo build --release` before testing"
-        } else {
-            "no rustfmt bin, try running `cargo build` before testing"
-        }
-    );
-    me
+    &RUSTFMT_PATH
 }
 
 #[test]
@@ -933,9 +935,9 @@ fn verify_check_works() {
     init_log();
     let temp_file = make_temp_file("temp_check.rs");
 
-    Command::new(rustfmt().to_str().unwrap())
+    Command::new(rustfmt())
         .arg("--check")
-        .arg(temp_file.path.to_str().unwrap())
+        .arg(&temp_file.path)
         .status()
         .expect("run with check option failed");
 }
@@ -944,7 +946,7 @@ fn verify_check_works() {
 fn verify_check_works_with_stdin() {
     init_log();
 
-    let mut child = Command::new(rustfmt().to_str().unwrap())
+    let mut child = Command::new(rustfmt())
         .arg("--check")
         .stdin(Stdio::piped())
         .stderr(Stdio::piped())
@@ -954,7 +956,7 @@ fn verify_check_works_with_stdin() {
     {
         let stdin = child.stdin.as_mut().expect("Failed to open stdin");
         stdin
-            .write_all("fn main() {}\n".as_bytes())
+            .write_all(b"fn main() {}\n")
             .expect("Failed to write to rustfmt --check");
     }
     let output = child
@@ -967,7 +969,7 @@ fn verify_check_works_with_stdin() {
 fn verify_check_l_works_with_stdin() {
     init_log();
 
-    let mut child = Command::new(rustfmt().to_str().unwrap())
+    let mut child = Command::new(rustfmt())
         .arg("--check")
         .arg("-l")
         .stdin(Stdio::piped())
@@ -979,7 +981,7 @@ fn verify_check_l_works_with_stdin() {
     {
         let stdin = child.stdin.as_mut().expect("Failed to open stdin");
         stdin
-            .write_all("fn main()\n{}\n".as_bytes())
+            .write_all(b"fn main()\n{}\n")
             .expect("Failed to write to rustfmt --check");
     }
     let output = child