Auto merge of #6787 - ehuss:code-cleanup, r=alexcrichton

Code cleanup

I think these changes should not be controversial, at least it looks cleaner to me. Split up into separate commits for different things.

Author: bors

src/bin/cargo/cli.rs

@@ -47,7 +47,7 @@ Run with 'cargo -Z [FLAG] [SUBCOMMAND]'"
         return Ok(());
     }
 
-    if let Some(ref code) = args.value_of("explain") {
+    if let Some(code) = args.value_of("explain") {
         let mut procss = config.rustc(None)?.process();
         procss.arg("--explain").arg(code).exec()?;
         return Ok(());

src/bin/cargo/main.rs

@@ -1,6 +1,8 @@
 #![warn(rust_2018_idioms)] // while we're getting used to 2018
 #![allow(clippy::too_many_arguments)] // large project
 #![allow(clippy::redundant_closure)] // there's a false positive
+#![warn(clippy::needless_borrow)]
+#![warn(clippy::redundant_clone)]
 
 use std::collections::BTreeSet;
 use std::env;

src/cargo/core/compiler/build_plan.rs

@@ -113,7 +113,7 @@ impl BuildPlan {
         let id = self.plan.invocations.len();
         self.invocation_map.insert(unit.buildkey(), id);
         let deps = cx
-            .dep_targets(&unit)
+            .dep_targets(unit)
             .iter()
             .map(|dep| self.invocation_map[&dep.buildkey()])
             .collect();

src/cargo/core/compiler/compilation.rs

@@ -120,7 +120,7 @@ impl<'cfg> Compilation<'cfg> {
             rustc_process: rustc,
             host: bcx.host_triple().to_string(),
             target: bcx.target_triple().to_string(),
-            target_runner: target_runner(&bcx)?,
+            target_runner: target_runner(bcx)?,
         })
     }
 

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

@@ -491,7 +491,7 @@ fn compute_metadata<'a, 'cfg>(
     // settings like debuginfo and whatnot.
     unit.profile.hash(&mut hasher);
     unit.mode.hash(&mut hasher);
-    if let Some(ref args) = bcx.extra_args_for(unit) {
+    if let Some(args) = bcx.extra_args_for(unit) {
         args.hash(&mut hasher);
     }
 

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

@@ -474,11 +474,11 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
         for unit in keys {
             for output in self.outputs(unit)?.iter() {
                 if let Some(other_unit) = output_collisions.insert(output.path.clone(), unit) {
-                    report_collision(unit, &other_unit, &output.path)?;
+                    report_collision(unit, other_unit, &output.path)?;
                 }
                 if let Some(hardlink) = output.hardlink.as_ref() {
                     if let Some(other_unit) = output_collisions.insert(hardlink.clone(), unit) {
-                        report_collision(unit, &other_unit, hardlink)?;
+                        report_collision(unit, other_unit, hardlink)?;
                     }
                 }
                 if let Some(ref export_path) = output.export_path {
@@ -488,7 +488,7 @@ impl<'a, 'cfg> Context<'a, 'cfg> {
                              {}\
                              The exported filenames should be unique.\n\
                              {}",
-                            describe_collision(unit, &other_unit, &export_path),
+                            describe_collision(unit, other_unit, export_path),
                             suggestion
                         ))?;
                     }

src/cargo/core/compiler/custom_build.rs

@@ -162,7 +162,7 @@ fn build_work<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoRes
         .env(
             "TARGET",
             &match unit.kind {
-                Kind::Host => &bcx.host_triple(),
+                Kind::Host => bcx.host_triple(),
                 Kind::Target => bcx.target_triple(),
             },
         )

src/cargo/core/compiler/fingerprint.rs

@@ -682,7 +682,7 @@ fn calculate<'a, 'cfg>(
         local.extend(local_fingerprint_run_custom_build_deps(cx, unit));
         local
     } else {
-        let fingerprint = pkg_fingerprint(&cx.bcx, unit.pkg)?;
+        let fingerprint = pkg_fingerprint(cx.bcx, unit.pkg)?;
         vec![LocalFingerprint::Precalculated(fingerprint)]
     };
 
@@ -701,7 +701,7 @@ fn calculate<'a, 'cfg>(
         profile: profile_hash,
         // Note that .0 is hashed here, not .1 which is the cwd. That doesn't
         // actually affect the output artifact so there's no need to hash it.
-        path: util::hash_u64(&super::path_args(&cx.bcx, unit).0),
+        path: util::hash_u64(&super::path_args(cx.bcx, unit).0),
         features: format!("{:?}", bcx.resolve.features_sorted(unit.pkg.package_id())),
         deps,
         local,
@@ -855,7 +855,7 @@ fn build_script_local_fingerprints<'a, 'cfg>(
     let output = deps.build_script_output.clone();
     if deps.rerun_if_changed.is_empty() && deps.rerun_if_env_changed.is_empty() {
         debug!("old local fingerprints deps");
-        let s = pkg_fingerprint(&cx.bcx, unit.pkg)?;
+        let s = pkg_fingerprint(cx.bcx, unit.pkg)?;
         return Ok((vec![LocalFingerprint::Precalculated(s)], Some(output)));
     }
 

src/cargo/core/compiler/mod.rs

@@ -640,7 +640,7 @@ fn rustdoc<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoResult
 
     add_error_format(bcx, &mut rustdoc);
 
-    if let Some(ref args) = bcx.extra_args_for(unit) {
+    if let Some(args) = bcx.extra_args_for(unit) {
         rustdoc.args(args);
     }
 
@@ -831,7 +831,7 @@ fn build_base_args<'a, 'cfg>(
         cmd.arg("-C").arg(format!("debuginfo={}", debuginfo));
     }
 
-    if let Some(ref args) = bcx.extra_args_for(unit) {
+    if let Some(args) = bcx.extra_args_for(unit) {
         cmd.args(args);
     }
 

src/cargo/core/package.rs

@@ -105,7 +105,7 @@ impl ser::Serialize for Package {
 
         SerializedPackage {
             name: &*package_id.name(),
-            version: &package_id.version(),
+            version: package_id.version(),
             id: package_id,
             license,
             license_file,
@@ -740,7 +740,7 @@ impl<'a, 'cfg> Downloads<'a, 'cfg> {
             self.set.multi.messages(|msg| {
                 let token = msg.token().expect("failed to read token");
                 let handle = &pending[&token].1;
-                if let Some(result) = msg.result_for(&handle) {
+                if let Some(result) = msg.result_for(handle) {
                     results.push((token, result));
                 } else {
                     debug!("message without a result (?)");