Auto merge of #65733 - Centril:rollup-0zth66f, r=Centril

Rollup of 12 pull requests

Successful merges:

 - #64178 (More Clippy fixes for alloc, core and std)
 - #65144 (Add Cow::is_borrowed and Cow::is_owned)
 - #65193 (Lockless LintStore)
 - #65479 (Add the `matches!( $expr, $pat ) -> bool` macro)
 - #65518 (Avoid ICE when checking `Destination` of `break` inside a closure)
 - #65583 (rustc_metadata: use a table for super_predicates, fn_sig, impl_trait_ref.)
 - #65641 (Derive `Rustc{En,De}codable` for `TokenStream`.)
 - #65648 (Eliminate `intersect_opt`.)
 - #65657 (Remove `InternedString`)
 - #65691 (Update E0659 error code long explanation to 2018 edition)
 - #65696 (Fix an issue with const inference variables sticking around under Chalk + NLL)
 - #65704 (relax ExactSizeIterator bound on write_bytes)

Failed merges:

r? @ghost

7 files changed, 9 insertions, 10 deletions

diff --git a/src/libstd/sys/unix/rand.rs b/src/libstd/sys/unix/rand.rs
index c5be1763302..be112f6fc03 100644
--- a/src/libstd/sys/unix/rand.rs
+++ b/src/libstd/sys/unix/rand.rs
@@ -8,7 +8,7 @@ pub fn hashmap_random_keys() -> (u64, u64) {
                                              mem::size_of_val(&v));
         imp::fill_bytes(view);
     }
-    return v
+    v
 }
 
 #[cfg(all(unix,
diff --git a/src/libstd/sys/windows/handle.rs b/src/libstd/sys/windows/handle.rs
index 3e5aa693354..3986cda1a50 100644
--- a/src/libstd/sys/windows/handle.rs
+++ b/src/libstd/sys/windows/handle.rs
@@ -46,7 +46,7 @@ impl Handle {
     pub fn into_raw(self) -> c::HANDLE {
         let ret = self.raw();
         mem::forget(self);
-        return ret;
+        ret
     }
 }
 
diff --git a/src/libstd/sys/windows/mutex.rs b/src/libstd/sys/windows/mutex.rs
index 37cbdcefced..79dec1adf4b 100644
--- a/src/libstd/sys/windows/mutex.rs
+++ b/src/libstd/sys/windows/mutex.rs
@@ -144,7 +144,7 @@ fn kind() -> Kind {
         Some(..) => Kind::SRWLock,
     };
     KIND.store(ret as usize, Ordering::SeqCst);
-    return ret;
+    ret
 }
 
 pub struct ReentrantMutex { inner: UnsafeCell<MaybeUninit<c::CRITICAL_SECTION>> }
diff --git a/src/libstd/sys/windows/process.rs b/src/libstd/sys/windows/process.rs
index 8658deb8546..096b7bea8a5 100644
--- a/src/libstd/sys/windows/process.rs
+++ b/src/libstd/sys/windows/process.rs
@@ -257,7 +257,7 @@ impl Stdio {
                         let ret = io.duplicate(0, true,
                                                c::DUPLICATE_SAME_ACCESS);
                         io.into_raw();
-                        return ret
+                        ret
                     }
                     Err(..) => Ok(Handle::new(c::INVALID_HANDLE_VALUE)),
                 }
@@ -472,9 +472,8 @@ fn make_command_line(prog: &OsStr, args: &[OsString]) -> io::Result<Vec<u16>> {
             cmd.push('"' as u16);
         }
 
-        let mut iter = arg.encode_wide();
         let mut backslashes: usize = 0;
-        while let Some(x) = iter.next() {
+        for x in arg.encode_wide() {
             if x == '\\' as u16 {
                 backslashes += 1;
             } else {
diff --git a/src/libstd/sys/windows/rand.rs b/src/libstd/sys/windows/rand.rs
index c9bcb5d7415..993831bec18 100644
--- a/src/libstd/sys/windows/rand.rs
+++ b/src/libstd/sys/windows/rand.rs
@@ -13,7 +13,7 @@ pub fn hashmap_random_keys() -> (u64, u64) {
         panic!("couldn't generate random bytes: {}",
                io::Error::last_os_error());
     }
-    return v
+    v
 }
 
 #[cfg(target_vendor = "uwp")]
diff --git a/src/libstd/sys/windows/thread_local.rs b/src/libstd/sys/windows/thread_local.rs
index 4c9734fa0aa..728257cdd4b 100644
--- a/src/libstd/sys/windows/thread_local.rs
+++ b/src/libstd/sys/windows/thread_local.rs
@@ -52,7 +52,7 @@ pub unsafe fn create(dtor: Option<Dtor>) -> Key {
     if let Some(f) = dtor {
         register_dtor(key, f);
     }
-    return key;
+    key
 }
 
 #[inline]
diff --git a/src/libstd/sys/windows/time.rs b/src/libstd/sys/windows/time.rs
index e0f0e3a1a45..bd533c93d43 100644
--- a/src/libstd/sys/windows/time.rs
+++ b/src/libstd/sys/windows/time.rs
@@ -80,7 +80,7 @@ impl SystemTime {
         unsafe {
             let mut t: SystemTime = mem::zeroed();
             c::GetSystemTimeAsFileTime(&mut t.t);
-            return t
+            t
         }
     }
 
@@ -228,7 +228,7 @@ mod perf_counter {
                 FREQUENCY = frequency;
                 STATE.store(2, SeqCst);
             }
-            return frequency;
+            frequency
         }
     }