Auto merge of #7444 - matthiaskrgr:clippy_v8, r=Eh2406

 fix a bunch of clippy warnings

crates/cargo-test-support/src/lib.rs

@@ -1158,9 +1158,7 @@ impl Execs {
 
  // It's easier to read tabs in outputs if they don't show up as literal
  // hidden characters
- let matcher = matcher.replace("\t", "<tab>");
-
- matcher
+ matcher.replace("\t", "<tab>")
  }
 
  fn match_std(

src/cargo/core/compiler/context/compilation_files.rs

@@ -372,9 +372,9 @@ impl<'a, 'cfg: 'a> CompilationFiles<'a, 'cfg> {
  None
  } else {
  self.export_dir.as_ref().and_then(|export_dir| {
- hardlink.as_ref().and_then(|hardlink| {
- Some(export_dir.join(hardlink.file_name().unwrap()))
- })
+ hardlink
+ .as_ref()
+  .map(|hardlink| export_dir.join(hardlink.file_name().unwrap()))
  })
  };
  ret.push(OutputFile {

src/cargo/core/compiler/custom_build.rs

@@ -518,7 +518,7 @@ impl BuildOutput {
  // common with tools like pkg-config
  // e.g. -L/some/dir/local/lib or -licui18n
  let (flag, mut value) = flag.split_at(2);
- if value.len() == 0 {
+ if value.is_empty() {
  value = match flags_iter.next() {
  Some(v) => v,
  None => failure::bail! {

src/cargo/core/compiler/layout.rs

@@ -217,7 +217,7 @@ impl Layout {
  paths::create_dir_all(&self.examples)?;
  paths::create_dir_all(&self.build)?;
 
- return Ok(());
+ Ok(())
  }
 
  /// Fetch the destination path for final artifacts (`/…/target/debug`).

src/cargo/core/resolver/errors.rs

@@ -252,7 +252,7 @@ pub(super) fn activation_error(
  // Maybe the user mistyped the name? Like `dep-thing` when `Dep_Thing`
  // was meant. So we try asking the registry for a `fuzzy` search for suggestions.
  let mut candidates = Vec::new();
- if let Err(e) = registry.query(&new_dep, &mut |s| candidates.push(s.clone()), true) {
+ if let Err(e) = registry.query(&new_dep, &mut |s| candidates.push(s), true) {
  return to_resolve_err(e);
  };
  candidates.sort_unstable_by(|a, b| a.name().cmp(&b.name()));

src/cargo/sources/registry/mod.rs

@@ -604,7 +604,7 @@ impl<'cfg> Source for RegistrySource<'cfg> {
 
  fn download(&mut self, package: PackageId) -> CargoResult<MaybePackage> {
  let hash = self.index.hash(package, &mut *self.ops)?;
- match self.ops.download(package, &hash)? {
+ match self.ops.download(package, hash)? {
  MaybeLock::Ready(file) => self.get_pkg(package, &file).map(MaybePackage::Ready),
  MaybeLock::Download { url, descriptor } => {
  Ok(MaybePackage::Download { url, descriptor })
@@ -614,7 +614,7 @@ impl<'cfg> Source for RegistrySource<'cfg> {
 
  fn finish_download(&mut self, package: PackageId, data: Vec<u8>) -> CargoResult<Package> {
  let hash = self.index.hash(package, &mut *self.ops)?;
- let file = self.ops.finish_download(package, &hash, &data)?;
+ let file = self.ops.finish_download(package, hash, &data)?;
  self.get_pkg(package, &file)
  }
 

src/cargo/util/dependency_queue.rs

@@ -107,14 +107,14 @@ impl<N: Hash + Eq + Clone, E: Eq + Hash + Clone, V> DependencyQueue<N, E, V> {
  .get(key)
  .into_iter()
  .flat_map(|it| it.values())
- .flat_map(|set| set)
+ .flatten()
  {
  set.extend(depth(dep, map, results).iter().cloned())
  }
 
  let slot = results.get_mut(key).unwrap();
  *slot = set;
- return &*slot;
+ &*slot
  }
  }
 

src/cargo/util/toml/mod.rs

@@ -954,7 +954,7 @@ impl TomlManifest {
  .or_else(|| me.build_dependencies2.as_ref());
  process_dependencies(&mut cx, build_deps, Some(Kind::Build))?;
 
- for (name, platform) in me.target.iter().flat_map(|t| t) {
+ for (name, platform) in me.target.iter().flatten() {
  cx.platform = Some(name.parse()?);
  process_dependencies(&mut cx, platform.dependencies.as_ref(), None)?;
  let build_deps = platform
@@ -1210,7 +1210,7 @@ impl TomlManifest {
  bail!("cannot specify both [replace] and [patch]");
  }
  let mut replace = Vec::new();
- for (spec, replacement) in self.replace.iter().flat_map(|x| x) {
+ for (spec, replacement) in self.replace.iter().flatten() {
  let mut spec = PackageIdSpec::parse(spec).chain_err(|| {
  format!(
  "replacements must specify a valid semver \
@@ -1252,7 +1252,7 @@ impl TomlManifest {
 
  fn patch(&self, cx: &mut Context<'_, '_>) -> CargoResult<HashMap<Url, Vec<Dependency>>> {
  let mut patch = HashMap::new();
- for (url, deps) in self.patch.iter().flat_map(|x| x) {
+ for (url, deps) in self.patch.iter().flatten() {
  let url = match &url[..] {
  CRATES_IO_REGISTRY => CRATES_IO_INDEX.parse().unwrap(),
  _ => cx
@@ -1469,7 +1469,7 @@ impl DetailedTomlDependency {
  Some(id) => Dependency::parse(pkg_name, version, new_source_id, id, cx.config)?,
  None => Dependency::parse_no_deprecated(pkg_name, version, new_source_id)?,
  };
- dep.set_features(self.features.iter().flat_map(|x| x))
+ dep.set_features(self.features.iter().flatten())
  .set_default_features(
  self.default_features
  .or(self.default_features2)

tests/testsuite/standard_lib.rs

@@ -104,10 +104,10 @@ fn setup() -> Option<Setup> {
  .build();
  p.cargo("build").run();
 
- return Some(Setup {
+ Some(Setup {
  rustc_wrapper: p.bin("foo"),
  real_sysroot: paths::sysroot(),
- });
+ })
 }
 
 fn enable_build_std(e: &mut Execs, setup: &Setup, arg: Option<&str>) {