Auto merge of #5876 - matthiaskrgr:clippy_2, r=alexcrichton

fix a bunch of clippy warnings

 (invocation: cargo clippy --all-targets --all-features -- --cap-lints warn )

Author: bors

src/cargo/core/compiler/custom_build.rs

@@ -322,7 +322,7 @@ fn build_work<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoRes
         } else {
             state.running(&cmd);
             let output = if extra_verbose {
-                state.capture_output(cmd, true)
+                state.capture_output(&cmd, true)
             } else {
                 cmd.exec_with_output()
             };

src/cargo/core/compiler/job_queue.rs

@@ -110,7 +110,7 @@ impl<'a> JobState<'a> {
 
     pub fn capture_output(
         &self,
-        cmd: ProcessBuilder,
+        cmd: &ProcessBuilder,
         print_output: bool,
     ) -> CargoResult<Output> {
         cmd.exec_with_streaming(

src/cargo/core/compiler/mod.rs

@@ -118,7 +118,7 @@ impl Executor for DefaultExecutor {
         _mode: CompileMode,
         state: &job_queue::JobState<'_>,
     ) -> CargoResult<()> {
-        state.capture_output(cmd, false).map(drop)
+        state.capture_output(&cmd, false).map(drop)
     }
 }
 
@@ -643,7 +643,7 @@ fn rustdoc<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoResult
                     false,
                 ).map(drop)
         } else if should_capture_output {
-            state.capture_output(rustdoc, false).map(drop)
+            state.capture_output(&rustdoc, false).map(drop)
         } else {
             rustdoc.exec()
         };

src/cargo/lib.rs

@@ -110,7 +110,7 @@ impl fmt::Display for VersionInfo {
         if let Some(channel) = self.cfg_info.as_ref().map(|ci| &ci.release_channel) {
             if channel != "stable" {
                 write!(f, "-{}", channel)?;
-                let empty = String::from("");
+                let empty = String::new();
                 write!(f, "{}", self.pre_release.as_ref().unwrap_or(&empty))?;
             }
         };

src/cargo/ops/fix.rs

@@ -270,7 +270,7 @@ fn rustfix_crate(lock_addr: &str, rustc: &Path, filename: &Path, args: &FixArgs)
         rustfix_and_fix(&mut fixes, rustc, filename, args)?;
         let mut progress_yet_to_be_made = false;
         for (path, file) in fixes.files.iter_mut() {
-            if file.errors_applying_fixes.len() == 0 {
+            if file.errors_applying_fixes.is_empty() {
                 continue
             }
             // If anything was successfully fixed *and* there's at least one
@@ -523,7 +523,7 @@ impl FixArgs {
             ret.prepare_for_edition = PrepareFor::Next;
         }
         ret.idioms = env::var(IDIOMS_ENV).is_ok();
-        return ret
+        ret
     }
 
     fn apply(&self, cmd: &mut Command) {
@@ -535,10 +535,7 @@ impl FixArgs {
         if let Some(edition) = &self.enabled_edition {
             cmd.arg("--edition").arg(edition);
             if self.idioms {
-                match &edition[..] {
-                    "2018" => { cmd.arg("-Wrust-2018-idioms"); }
-                    _ => {}
-                }
+                if edition == "2018" { cmd.arg("-Wrust-2018-idioms"); }
             }
         }
         match &self.prepare_for_edition {

src/cargo/util/diagnostic_server.rs

@@ -199,7 +199,7 @@ guide can be found at
                     file,
                     match edition {
                         Some(s) => format!("with the {} edition", s),
-                        None => format!("without an edition"),
+                        None => "without an edition".to_string(),
                     },
                 ))?;
                 Ok(())

tests/testsuite/build.rs

@@ -1024,12 +1024,12 @@ fn cargo_compile_with_downloaded_dependency_with_offline() {
         p2.cargo("build")
             .masquerade_as_nightly_cargo()
             .arg("-Zoffline"),
-        execs().with_stderr(format!(
+        execs().with_stderr(
             "\
 [COMPILING] present_dep v1.2.3
 [COMPILING] bar v0.1.0 ([..])
 [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]"
-        )),
+    ),
     );
 }
 
@@ -4439,7 +4439,7 @@ fn target_edition_feature_gated() {
 
     assert_that(
         p.cargo("build").arg("-v").masquerade_as_nightly_cargo(),
-        execs().with_status(101).with_stderr(format!(
+        execs().with_status(101).with_stderr(
             "\
 error: failed to parse manifest at `[..]`
 
@@ -4451,7 +4451,7 @@ Caused by:
 
 consider adding `cargo-features = [\"edition\"]` to the manifest
 "
-        )),
+        ),
     );
 }
 

tests/testsuite/concurrent.rs

@@ -52,7 +52,7 @@ fn multiple_installs() {
 
 #[test]
 fn concurrent_installs() {
-    const LOCKED_BUILD: &'static str = "waiting for file lock on build directory";
+    const LOCKED_BUILD: &str = "waiting for file lock on build directory";
 
     pkg("foo", "0.0.1");
     pkg("bar", "0.0.1");

tests/testsuite/config.rs

@@ -4,6 +4,7 @@ use cargo::util::toml::{self, VecStringOrBool as VSOB};
 use cargo::CargoError;
 use support::{execs, lines_match, paths, project};
 use support::hamcrest::assert_that;
+use std::borrow::Borrow;
 use std::collections;
 use std::fs;
 
@@ -68,8 +69,9 @@ fn new_config(env: &[(&str, &str)]) -> Config {
     config
 }
 
-fn assert_error(error: CargoError, msgs: &str) {
+fn assert_error<E: Borrow<CargoError>>(error: E, msgs: &str) {
     let causes = error
+        .borrow()
         .iter_chain()
         .map(|e| e.to_string())
         .collect::<Vec<_>>()

tests/testsuite/corrupt_git.rs

@@ -38,7 +38,7 @@ fn deleting_database_files() {
 
     let mut files = Vec::new();
     find_files(&paths::home().join(".cargo/git/db"), &mut files);
-    assert!(files.len() > 0);
+    assert!(!files.is_empty());
 
     let log = "cargo::sources::git=trace";
     for file in files {
@@ -120,7 +120,7 @@ fn deleting_checkout_files() {
         .join(".git");
     let mut files = Vec::new();
     find_files(&dir, &mut files);
-    assert!(files.len() > 0);
+    assert!(!files.is_empty());
 
     let log = "cargo::sources::git=trace";
     for file in files {