Rollup merge of #69802 - matthiaskrgr:cl1ppy, r=Dylan-DPC

fix more clippy findings

* reduce references on match patterns (clippy::match_ref_pats)
* Use writeln!(fmt, "word") instead of write!(fmt, "word\n") (clippy::write_with_newline)
* libtest: remove redundant argument to writeln!() (clippy::writeln_empty_string)
* remove unneeded mutable references (cippy::unnecessary_mut_passed)
* libtest: declare variables as floats instead of casting them (clippy::unnecessary_cast)
* rustdoc: remove redundant static lifetimes (clippy::redundant_static_lifetimes)
* call .as_deref() instead of .as_ref().map(Deref::deref) (clippy::option_as_ref_deref)
* iterate over a maps values directly. (clippy::for_kv_map)
* rustdoc: simplify boolean condition (clippy::nonminimal_bool)
* Use ?-operator in more places (clippy::question_mark, had some false negatives fixed recently)
* rustdoc: Use .any(p) instead of find(p).is_some(). (clippy::search_is_some)
* rustdoc: don't call into_iter() on iterator. (clippy::identity_conversion)

3 files changed, 6 insertions, 6 deletions

diff --git a/src/libstd/sys_common/backtrace.rs b/src/libstd/sys_common/backtrace.rs
index 289ee07babf..2c7ba8f8ea1 100644
--- a/src/libstd/sys_common/backtrace.rs
+++ b/src/libstd/sys_common/backtrace.rs
@@ -70,7 +70,7 @@ unsafe fn _print_fmt(fmt: &mut fmt::Formatter<'_>, print_fmt: PrintFmt) -> fmt::
     let mut print_path = move |fmt: &mut fmt::Formatter<'_>, bows: BytesOrWideString<'_>| {
         output_filename(fmt, bows, print_fmt, cwd.as_ref())
     };
-    write!(fmt, "stack backtrace:\n")?;
+    writeln!(fmt, "stack backtrace:")?;
     let mut bt_fmt = BacktraceFmt::new(fmt, print_fmt, &mut print_path);
     bt_fmt.add_context()?;
     let mut idx = 0;
diff --git a/src/libstd/sys_common/process.rs b/src/libstd/sys_common/process.rs
index 042641852b3..f3a2962098b 100644
--- a/src/libstd/sys_common/process.rs
+++ b/src/libstd/sys_common/process.rs
@@ -47,7 +47,7 @@ impl CommandEnv {
             }
         }
         for (key, maybe_val) in self.vars.iter() {
-            if let &Some(ref val) = maybe_val {
+            if let Some(ref val) = maybe_val {
                 env::set_var(key, val);
             } else {
                 env::remove_var(key);
diff --git a/src/libstd/sys_common/wtf8.rs b/src/libstd/sys_common/wtf8.rs
index 1d96cdfe460..7509e1ee35d 100644
--- a/src/libstd/sys_common/wtf8.rs
+++ b/src/libstd/sys_common/wtf8.rs
@@ -603,8 +603,8 @@ impl Wtf8 {
         if len < 3 {
             return None;
         }
-        match &self.bytes[(len - 3)..] {
-            &[0xED, b2 @ 0xA0..=0xAF, b3] => Some(decode_surrogate(b2, b3)),
+        match self.bytes[(len - 3)..] {
+            [0xED, b2 @ 0xA0..=0xAF, b3] => Some(decode_surrogate(b2, b3)),
             _ => None,
         }
     }
@@ -615,8 +615,8 @@ impl Wtf8 {
         if len < 3 {
             return None;
         }
-        match &self.bytes[..3] {
-            &[0xED, b2 @ 0xB0..=0xBF, b3] => Some(decode_surrogate(b2, b3)),
+        match self.bytes[..3] {
+            [0xED, b2 @ 0xB0..=0xBF, b3] => Some(decode_surrogate(b2, b3)),
             _ => None,
         }
     }