More Clippy fixes for alloc, core and std

src/liballoc/collections/vec_deque.rs

@@ -1817,7 +1817,7 @@ impl<T> VecDeque<T> {
             }
         }
 
-        return elem;
+        elem
     }
 
     /// Splits the `VecDeque` into two at the given index.

src/liballoc/str.rs

@@ -456,7 +456,7 @@ impl str {
                 }
             }
         }
-        return s;
+        s
     }
 
     /// Converts a [`Box<str>`] into a [`String`] without copying or allocating.

src/liballoc/sync.rs

@@ -1638,7 +1638,7 @@ impl<T: ?Sized> Clone for Weak<T> {
             }
         }
 
-        return Weak { ptr: self.ptr };
+        Weak { ptr: self.ptr }
     }
 }
 

src/libcore/fmt/mod.rs

@@ -2025,7 +2025,7 @@ impl<T: ?Sized> Pointer for *const T {
         if f.alternate() {
             f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32);
 
-            if let None = f.width {
+            if f.width.is_none() {
                 f.width = Some(((mem::size_of::<usize>() * 8) / 4) + 2);
             }
         }

src/libcore/num/dec2flt/algorithm.rs

@@ -143,13 +143,12 @@ pub fn fast_path<T: RawFloat>(integral: &[u8], fractional: &[u8], e: i64) -> Opt
 /// > not a bound for the true error, but bounds the difference between the approximation z and
 /// > the best possible approximation that uses p bits of significand.)
 pub fn bellerophon<T: RawFloat>(f: &Big, e: i16) -> T {
-    let slop;
-    if f <= &Big::from_u64(T::MAX_SIG) {
+    let slop = if f <= &Big::from_u64(T::MAX_SIG) {
         // The cases abs(e) < log5(2^N) are in fast_path()
-        slop = if e >= 0 { 0 } else { 3 };
+        if e >= 0 { 0 } else { 3 }
     } else {
-        slop = if e >= 0 { 1 } else { 4 };
-    }
+        if e >= 0 { 1 } else { 4 }
+    };
     let z = rawfp::big_to_fp(f).mul(&power_of_ten(e)).normalize();
     let exp_p_n = 1 << (P - T::SIG_BITS as u32);
     let lowbits: i64 = (z.f % exp_p_n) as i64;

src/libcore/option.rs

@@ -837,9 +837,8 @@ impl<T> Option<T> {
     #[inline]
     #[stable(feature = "option_entry", since = "1.20.0")]
     pub fn get_or_insert_with<F: FnOnce() -> T>(&mut self, f: F) -> &mut T {
-        match *self {
-            None => *self = Some(f()),
-            _ => (),
+        if let None = *self {
+            *self = Some(f());
         }
 
         match *self {

src/libpanic_unwind/gcc.rs

@@ -156,21 +156,21 @@ unsafe extern "C" fn rust_eh_personality(version: c_int,
     if actions as i32 & uw::_UA_SEARCH_PHASE as i32 != 0 {
         match eh_action {
             EHAction::None |
-            EHAction::Cleanup(_) => return uw::_URC_CONTINUE_UNWIND,
-            EHAction::Catch(_) => return uw::_URC_HANDLER_FOUND,
-            EHAction::Terminate => return uw::_URC_FATAL_PHASE1_ERROR,
+            EHAction::Cleanup(_) => uw::_URC_CONTINUE_UNWIND,
+            EHAction::Catch(_) => uw::_URC_HANDLER_FOUND,
+            EHAction::Terminate => uw::_URC_FATAL_PHASE1_ERROR,
         }
     } else {
         match eh_action {
-            EHAction::None => return uw::_URC_CONTINUE_UNWIND,
+            EHAction::None => uw::_URC_CONTINUE_UNWIND,
             EHAction::Cleanup(lpad) |
             EHAction::Catch(lpad) => {
                 uw::_Unwind_SetGR(context, UNWIND_DATA_REG.0, exception_object as uintptr_t);
                 uw::_Unwind_SetGR(context, UNWIND_DATA_REG.1, 0);
                 uw::_Unwind_SetIP(context, lpad);
-                return uw::_URC_INSTALL_CONTEXT;
+                uw::_URC_INSTALL_CONTEXT
             }
-            EHAction::Terminate => return uw::_URC_FATAL_PHASE2_ERROR,
+            EHAction::Terminate => uw::_URC_FATAL_PHASE2_ERROR,
         }
     }
 }

src/libpanic_unwind/seh64_gnu.rs

@@ -46,7 +46,7 @@ pub fn payload() -> *mut u8 {
 
 pub unsafe fn cleanup(ptr: *mut u8) -> Box<dyn Any + Send> {
     let panic_ctx = Box::from_raw(ptr as *mut PanicData);
-    return panic_ctx.data;
+    panic_ctx.data
 }
 
 // SEH doesn't support resuming unwinds after calling a landing pad like

src/libstd/panicking.rs

@@ -217,7 +217,7 @@ pub fn update_panic_count(amt: isize) -> usize {
     PANIC_COUNT.with(|c| {
         let next = (c.get() as isize + amt) as usize;
         c.set(next);
-        return next
+        next
     })
 }
 

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,

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
     }
 }
 

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>> }

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 {

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")]

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]

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
         }
     }
 

src/libstd/thread/local.rs

@@ -509,9 +509,8 @@ pub mod os {
         pub unsafe fn get(&'static self, init: fn() -> T) -> Option<&'static T> {
             let ptr = self.os.get() as *mut Value<T>;
             if ptr as usize > 1 {
-                match (*ptr).inner.get() {
-                    Some(ref value) => return Some(value),
-                    None => {},
+                if let Some(ref value) = (*ptr).inner.get() {
+                    return Some(value);
                 }
             }
             self.try_initialize(init)

src/libtest/bench.rs

@@ -48,7 +48,7 @@ impl Bencher {
         F: FnMut(&mut Bencher),
     {
         f(self);
-        return self.summary;
+        self.summary
     }
 }
 
@@ -116,7 +116,7 @@ where
     for _ in 0..k {
         black_box(inner());
     }
-    return ns_from_dur(start.elapsed());
+    ns_from_dur(start.elapsed())
 }
 
 pub fn iter<T, F>(inner: &mut F) -> stats::Summary

src/libtest/cli.rs

@@ -149,7 +149,7 @@ fn optgroups() -> getopts::Options {
             `CRITICAL_TIME` here means the limit that should not be exceeded by test.
             "
         );
-    return opts;
+    opts
 }
 
 fn usage(binary: &str, options: &getopts::Options) {

src/libtest/console.rs

@@ -296,7 +296,7 @@ pub fn run_tests_console(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> io::Resu
 
     assert!(st.current_test_count() == st.total);
 
-    return out.write_run_finish(&st);
+    out.write_run_finish(&st)
 }
 
 // Calculates padding for given test description.