use sort_by_key() instead of comparing by keys manually

replace format!() macro by String::from()
use eprintln() instead of manually writing to std::io::stderr

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

@@ -1233,7 +1233,7 @@ impl Execs {
                         None => failures.push(e_line),
                     }
                 }
-                if failures.len() > 0 {
+                if !failures.is_empty() {
                     return Err(format!(
                         "Did not find expected line(s):\n{}\n\
                          Remaining available output:\n{}\n",

src/cargo/core/resolver/errors.rs

@@ -254,7 +254,7 @@ pub(super) fn activation_error(
             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()));
+            candidates.sort_unstable_by_key(|a| a.name());
             candidates.dedup_by(|a, b| a.name() == b.name());
             let mut candidates: Vec<_> = candidates
                 .iter()

src/cargo/sources/git/utils.rs

@@ -901,7 +901,7 @@ pub fn fetch(
 
         GitReference::DefaultBranch => {
             // See the module docs for why we're fetching `master` here.
-            refspecs.push(format!("refs/heads/master:refs/remotes/origin/master"));
+            refspecs.push(String::from("refs/heads/master:refs/remotes/origin/master"));
             refspecs.push(String::from("HEAD:refs/remotes/origin/HEAD"));
         }
 

tests/testsuite/package.rs

@@ -1870,6 +1870,8 @@ fn long_file_names() {
         test_path.mkdir_p();
         let test_path = test_path.join(long_name);
         if let Err(e) = File::create(&test_path) {
+            // write to stderr directly to avoid output from being captured
+            // and always display text, even without --nocapture
             use std::io::Write;
             writeln!(
                 std::io::stderr(),