Remove needless returns detected by clippy in libraries

alloc/src/collections/vec_deque/iter.rs

@@ -73,7 +73,7 @@ impl<'a, T> Iterator for Iter<'a, T> {
     fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>> {
         let remaining = self.i1.advance_by(n);
         match remaining {
-            Ok(()) => return Ok(()),
+            Ok(()) => Ok(()),
             Err(n) => {
                 mem::swap(&mut self.i1, &mut self.i2);
                 self.i1.advance_by(n.get())
@@ -144,7 +144,7 @@ impl<'a, T> DoubleEndedIterator for Iter<'a, T> {
 
     fn advance_back_by(&mut self, n: usize) -> Result<(), NonZero<usize>> {
         match self.i2.advance_back_by(n) {
-            Ok(()) => return Ok(()),
+            Ok(()) => Ok(()),
             Err(n) => {
                 mem::swap(&mut self.i1, &mut self.i2);
                 self.i2.advance_back_by(n.get())

alloc/src/collections/vec_deque/iter_mut.rs

@@ -64,7 +64,7 @@ impl<'a, T> Iterator for IterMut<'a, T> {
 
     fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>> {
         match self.i1.advance_by(n) {
-            Ok(()) => return Ok(()),
+            Ok(()) => Ok(()),
             Err(remaining) => {
                 mem::swap(&mut self.i1, &mut self.i2);
                 self.i1.advance_by(remaining.get())
@@ -135,7 +135,7 @@ impl<'a, T> DoubleEndedIterator for IterMut<'a, T> {
 
     fn advance_back_by(&mut self, n: usize) -> Result<(), NonZero<usize>> {
         match self.i2.advance_back_by(n) {
-            Ok(()) => return Ok(()),
+            Ok(()) => Ok(()),
             Err(remaining) => {
                 mem::swap(&mut self.i1, &mut self.i2);
                 self.i2.advance_back_by(remaining.get())

alloc/src/vec/in_place_collect.rs

@@ -208,7 +208,7 @@ const fn needs_realloc<SRC, DEST>(src_cap: usize, dst_cap: usize) -> bool {
 
     // type layouts don't guarantee a fit, so do a runtime check to see if
     // the allocations happen to match
-    return src_cap > 0 && src_cap * mem::size_of::<SRC>() != dst_cap * mem::size_of::<DEST>();
+    src_cap > 0 && src_cap * mem::size_of::<SRC>() != dst_cap * mem::size_of::<DEST>()
 }
 
 /// This provides a shorthand for the source type since local type aliases aren't a thing.

alloc/src/vec/into_iter.rs

@@ -288,11 +288,11 @@ impl<T, A: Allocator> Iterator for IntoIter<T, A> {
 
         // Safety: `len` is larger than the array size. Copy a fixed amount here to fully initialize
         // the array.
-        return unsafe {
+        unsafe {
             ptr::copy_nonoverlapping(self.ptr.as_ptr(), raw_ary.as_mut_ptr() as *mut T, N);
             self.ptr = self.ptr.add(N);
             Ok(raw_ary.transpose().assume_init())
-        };
+        }
     }
 
     fn fold<B, F>(mut self, mut accum: B, mut f: F) -> B

core/src/ptr/metadata.rs

@@ -187,14 +187,14 @@ impl<Dyn: ?Sized> DynMetadata<Dyn> {
         // Consider a reference like `&(i32, dyn Send)`: the vtable will only store the size of the
         // `Send` part!
         // SAFETY: DynMetadata always contains a valid vtable pointer
-        return unsafe { crate::intrinsics::vtable_size(self.vtable_ptr() as *const ()) };
+        unsafe { crate::intrinsics::vtable_size(self.vtable_ptr() as *const ()) }
     }
 
     /// Returns the alignment of the type associated with this vtable.
     #[inline]
     pub fn align_of(self) -> usize {
         // SAFETY: DynMetadata always contains a valid vtable pointer
-        return unsafe { crate::intrinsics::vtable_align(self.vtable_ptr() as *const ()) };
+        unsafe { crate::intrinsics::vtable_align(self.vtable_ptr() as *const ()) }
     }
 
     /// Returns the size and alignment together as a `Layout`

core/src/str/pattern.rs

@@ -1814,7 +1814,7 @@ fn simd_contains(needle: &str, haystack: &str) -> Option<bool> {
             }
             mask &= !(1 << trailing);
         }
-        return false;
+        false
     };
 
     let test_chunk = |idx| -> u16 {
@@ -1830,7 +1830,7 @@ fn simd_contains(needle: &str, haystack: &str) -> Option<bool> {
         let both = eq_first.bitand(eq_last);
         let mask = both.to_bitmask() as u16;
 
-        return mask;
+        mask
     };
 
     let mut i = 0;

std/src/sys/pal/unix/linux/pidfd.rs

@@ -13,7 +13,7 @@ pub(crate) struct PidFd(FileDesc);
 
 impl PidFd {
     pub fn kill(&self) -> io::Result<()> {
-        return cvt(unsafe {
+        cvt(unsafe {
             libc::syscall(
                 libc::SYS_pidfd_send_signal,
                 self.0.as_raw_fd(),
@@ -22,15 +22,15 @@ impl PidFd {
                 0,
             )
         })
-        .map(drop);
+        .map(drop)
     }
 
     pub fn wait(&self) -> io::Result<ExitStatus> {
         let mut siginfo: libc::siginfo_t = unsafe { crate::mem::zeroed() };
         cvt(unsafe {
             libc::waitid(libc::P_PIDFD, self.0.as_raw_fd() as u32, &mut siginfo, libc::WEXITED)
         })?;
-        return Ok(ExitStatus::from_waitid_siginfo(siginfo));
+        Ok(ExitStatus::from_waitid_siginfo(siginfo))
     }
 
     pub fn try_wait(&self) -> io::Result<Option<ExitStatus>> {
@@ -45,9 +45,10 @@ impl PidFd {
             )
         })?;
         if unsafe { siginfo.si_pid() } == 0 {
-            return Ok(None);
+            Ok(None)
+        } else {
+            Ok(Some(ExitStatus::from_waitid_siginfo(siginfo)))
         }
-        return Ok(Some(ExitStatus::from_waitid_siginfo(siginfo)));
     }
 }
 

std/src/sys/pal/wasi/fs.rs

@@ -265,7 +265,7 @@ impl OpenOptions {
     pub fn new() -> OpenOptions {
         let mut base = OpenOptions::default();
         base.dirflags = wasi::LOOKUPFLAGS_SYMLINK_FOLLOW;
-        return base;
+        base
     }
 
     pub fn read(&mut self, read: bool) {
@@ -382,7 +382,7 @@ impl OpenOptions {
         base |= wasi::RIGHTS_PATH_UNLINK_FILE;
         base |= wasi::RIGHTS_POLL_FD_READWRITE;
 
-        return base;
+        base
     }
 
     fn rights_inheriting(&self) -> wasi::Rights {

std/src/sys/pal/wasi/helpers.rs

@@ -115,7 +115,7 @@ pub fn hashmap_random_keys() -> (u64, u64) {
         let len = mem::size_of_val(&ret);
         wasi::random_get(base, len).expect("random_get failure");
     }
-    return ret;
+    ret
 }
 
 #[inline]