Some minor code cleanup.

src/bin/cargo/main.rs

@@ -76,9 +76,8 @@ fn aliased_command(config: &Config, command: &str) -> CargoResult<Option<Vec<Str
         Err(_) => config.get::<Option<Vec<String>>>(&alias_name)?,
     };
 
-    let result = user_alias.or_else(|| match builtin_aliases_execs(command) {
-        Some(command_str) => Some(vec![command_str.1.to_string()]),
-        None => None,
+    let result = user_alias.or_else(|| {
+        builtin_aliases_execs(command).map(|command_str| vec![command_str.1.to_string()])
     });
     Ok(result)
 }

src/cargo/core/compiler/build_context/target_info.rs

@@ -699,10 +699,10 @@ impl RustcTargetData {
 
         Ok(RustcTargetData {
             rustc,
-            target_config,
-            target_info,
             host_config,
             host_info,
+            target_config,
+            target_info,
         })
     }
 
@@ -766,7 +766,7 @@ pub struct RustDocFingerprint {
 
 impl RustDocFingerprint {
     /// Read the `RustDocFingerprint` info from the fingerprint file.
-    fn read<'a, 'cfg>(cx: &Context<'a, 'cfg>) -> CargoResult<Self> {
+    fn read(cx: &Context<'_, '_>) -> CargoResult<Self> {
         let rustdoc_data = paths::read(&cx.files().host_root().join(".rustdoc_fingerprint.json"))?;
         serde_json::from_str(&rustdoc_data).map_err(|e| anyhow::anyhow!("{:?}", e))
     }
@@ -779,7 +779,7 @@ impl RustDocFingerprint {
         )
     }
 
-    fn remove_doc_dirs(doc_dirs: &Vec<&Path>) -> CargoResult<()> {
+    fn remove_doc_dirs(doc_dirs: &[&Path]) -> CargoResult<()> {
         doc_dirs
             .iter()
             .filter(|path| path.exists())
@@ -795,7 +795,7 @@ impl RustDocFingerprint {
     /// the rustdoc fingerprint info in order to guarantee that we won't end up with mixed
     /// versions of the `js/html/css` files that `rustdoc` autogenerates which do not have
     /// any versioning.
-    pub fn check_rustdoc_fingerprint<'a, 'cfg>(cx: &Context<'a, 'cfg>) -> CargoResult<()> {
+    pub fn check_rustdoc_fingerprint(cx: &Context<'_, '_>) -> CargoResult<()> {
         let actual_rustdoc_target_data = RustDocFingerprint {
             rustc_vv: cx.bcx.rustc().verbose_version.clone(),
         };

src/cargo/core/compiler/compilation.rs

@@ -341,8 +341,8 @@ impl<'cfg> Compilation<'cfg> {
         if self.config.cli_unstable().configurable_env {
             // Apply any environment variables from the config
             for (key, value) in self.config.env_config()?.iter() {
-                if value.is_force() || cmd.get_env(&key).is_none() {
-                    cmd.env(&key, value.resolve(&self.config));
+                if value.is_force() || cmd.get_env(key).is_none() {
+                    cmd.env(key, value.resolve(self.config));
                 }
             }
         }

src/cargo/core/package.rs

@@ -434,11 +434,11 @@ impl<'cfg> PackageSet<'cfg> {
         })
     }
 
-    pub fn package_ids<'a>(&'a self) -> impl Iterator<Item = PackageId> + 'a {
+    pub fn package_ids(&self) -> impl Iterator<Item = PackageId> + '_ {
         self.packages.keys().cloned()
     }
 
-    pub fn packages<'a>(&'a self) -> impl Iterator<Item = &'a Package> + 'a {
+    pub fn packages(&self) -> impl Iterator<Item = &Package> {
         self.packages.values().filter_map(|p| p.borrow())
     }
 

src/cargo/core/resolver/resolve.rs

@@ -236,7 +236,7 @@ unable to verify that `{0}` is the same as when the lockfile was generated
         self.graph.sort()
     }
 
-    pub fn iter<'a>(&'a self) -> impl Iterator<Item = PackageId> + 'a {
+    pub fn iter(&self) -> impl Iterator<Item = PackageId> + '_ {
         self.graph.iter().cloned()
     }
 

src/cargo/core/resolver/types.rs

@@ -173,7 +173,7 @@ impl DepsFrame {
             .unwrap_or(0)
     }
 
-    pub fn flatten<'a>(&'a self) -> impl Iterator<Item = (PackageId, Dependency)> + 'a {
+    pub fn flatten(&self) -> impl Iterator<Item = (PackageId, Dependency)> + '_ {
         self.remaining_siblings
             .clone()
             .map(move |(d, _, _)| (self.parent.package_id(), d))
@@ -247,7 +247,7 @@ impl RemainingDeps {
         }
         None
     }
-    pub fn iter<'a>(&'a mut self) -> impl Iterator<Item = (PackageId, Dependency)> + 'a {
+    pub fn iter(&mut self) -> impl Iterator<Item = (PackageId, Dependency)> + '_ {
         self.data.iter().flat_map(|(other, _)| other.flatten())
     }
 }

src/cargo/ops/cargo_new.rs

@@ -831,10 +831,7 @@ fn discover_author(path: &Path) -> (Option<String>, Option<String>) {
         .or_else(|| git_config.and_then(|g| g.get_string("user.name").ok()))
         .or_else(|| get_environment_variable(&name_variables[3..]));
 
-    let name = match name {
-        Some(namestr) => Some(namestr.trim().to_string()),
-        None => None,
-    };
+    let name = name.map(|namestr| namestr.trim().to_string());
 
     let email_variables = [
         "CARGO_EMAIL",

src/cargo/ops/cargo_test.rs

@@ -92,7 +92,7 @@ fn run_unit_tests(
                 "{} ({})",
                 test_path
                     .strip_prefix(unit.pkg.root())
-                    .unwrap_or(&test_path)
+                    .unwrap_or(test_path)
                     .display(),
                 path.strip_prefix(cwd).unwrap_or(path).display()
             )

src/cargo/sources/registry/index.rs

@@ -837,7 +837,7 @@ impl IndexSummary {
     }
 }
 
-fn split<'a>(haystack: &'a [u8], needle: u8) -> impl Iterator<Item = &'a [u8]> + 'a {
+fn split(haystack: &[u8], needle: u8) -> impl Iterator<Item = &[u8]> {
     struct Split<'a> {
         haystack: &'a [u8],
         needle: u8,

src/cargo/util/config/mod.rs

@@ -315,10 +315,9 @@ impl Config {
 
     /// Gets the default Cargo registry.
     pub fn default_registry(&self) -> CargoResult<Option<String>> {
-        Ok(match self.get_string("registry.default")? {
-            Some(registry) => Some(registry.val),
-            None => None,
-        })
+        Ok(self
+            .get_string("registry.default")?
+            .map(|registry| registry.val))
     }
 
     /// Gets a reference to the shell, e.g., for writing error messages.
@@ -808,10 +807,7 @@ impl Config {
             (false, _, false) => Verbosity::Normal,
         };
 
-        let cli_target_dir = match target_dir.as_ref() {
-            Some(dir) => Some(Filesystem::new(dir.clone())),
-            None => None,
-        };
+        let cli_target_dir = target_dir.as_ref().map(|dir| Filesystem::new(dir.clone()));
 
         self.shell().set_verbosity(verbosity);
         self.shell().set_color_choice(color)?;

src/cargo/util/process_builder.rs

@@ -276,9 +276,9 @@ impl ProcessBuilder {
         })()
         .chain_err(|| process_error(&format!("could not execute process {}", self), None, None))?;
         let output = Output {
+            status,
             stdout,
             stderr,
-            status,
         };
 
         {

tests/testsuite/old_cargos.rs

@@ -393,7 +393,7 @@ fn new_features() {
                 ..
             }) = err.downcast_ref::<ProcessError>()
             {
-                let stderr = std::str::from_utf8(&stderr).unwrap();
+                let stderr = std::str::from_utf8(stderr).unwrap();
                 if !stderr.contains(contents) {
                     tc_result.push(format!(
                         "{} expected to see error contents:\n{}\nbut saw:\n{}",
@@ -428,7 +428,7 @@ fn new_features() {
         }
 
         let which = "locked bar 1.0.0";
-        lock_bar_to(&version, 100);
+        lock_bar_to(version, 100);
         match run_cargo() {
             Ok(behavior) => {
                 check_lock!(tc_result, "bar", which, behavior.bar, "1.0.0");
@@ -441,7 +441,7 @@ fn new_features() {
         }
 
         let which = "locked bar 1.0.1";
-        lock_bar_to(&version, 101);
+        lock_bar_to(version, 101);
         match run_cargo() {
             Ok(behavior) => {
                 check_lock!(tc_result, "bar", which, behavior.bar, "1.0.1");
@@ -463,7 +463,7 @@ fn new_features() {
         }
 
         let which = "locked bar 1.0.2";
-        lock_bar_to(&version, 102);
+        lock_bar_to(version, 102);
         match run_cargo() {
             Ok(behavior) => {
                 check_lock!(tc_result, "bar", which, behavior.bar, "1.0.2");

tests/testsuite/update.rs

@@ -584,7 +584,7 @@ fn preserve_top_comment() {
     let mut lines = lockfile.lines().collect::<Vec<_>>();
     lines.insert(2, "# some other comment");
     let mut lockfile = lines.join("\n");
-    lockfile.push_str("\n"); // .lines/.join loses the last newline
+    lockfile.push('\n'); // .lines/.join loses the last newline
     println!("saving Cargo.lock contents:\n{}", lockfile);
 
     p.change_file("Cargo.lock", &lockfile);