Use field init shorthand where possible

Field init shorthand allows writing initializers like `tcx: tcx` as
`tcx`. The compiler already uses it extensively. Fix the last few places
where it isn't yet used.

Author: joshtriplett

alloc/src/rc.rs

@@ -795,7 +795,7 @@ impl<T, A: Allocator> Rc<T, A> {
         let uninit_ptr: NonNull<_> = (unsafe { &mut *uninit_raw_ptr }).into();
         let init_ptr: NonNull<RcInner<T>> = uninit_ptr.cast();
 
-        let weak = Weak { ptr: init_ptr, alloc: alloc };
+        let weak = Weak { ptr: init_ptr, alloc };
 
         // It's important we don't give up ownership of the weak pointer, or
         // else the memory might be freed by the time `data_fn` returns. If

alloc/src/sync.rs

@@ -784,7 +784,7 @@ impl<T, A: Allocator> Arc<T, A> {
         let uninit_ptr: NonNull<_> = (unsafe { &mut *uninit_raw_ptr }).into();
         let init_ptr: NonNull<ArcInner<T>> = uninit_ptr.cast();
 
-        let weak = Weak { ptr: init_ptr, alloc: alloc };
+        let weak = Weak { ptr: init_ptr, alloc };
 
         // It's important we don't give up ownership of the weak pointer, or
         // else the memory might be freed by the time `data_fn` returns. If

core/src/task/wake.rs

@@ -322,7 +322,7 @@ impl<'a> ContextBuilder<'a> {
         // SAFETY: LocalWaker is just Waker without thread safety
         let local_waker = unsafe { transmute(waker) };
         Self {
-            waker: waker,
+            waker,
             local_waker,
             ext: ExtData::None(()),
             _marker: PhantomData,

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

@@ -135,7 +135,7 @@ impl FileAttr {
             S_IFREG => DT_REG,
             _ => DT_UNKNOWN,
         };
-        FileType { mode: mode }
+        FileType { mode }
     }
 }
 

std/src/sys/pal/hermit/thread.rs

@@ -43,7 +43,7 @@ impl Thread {
             }
             Err(io::const_error!(io::ErrorKind::Uncategorized, "Unable to create thread!"))
         } else {
-            Ok(Thread { tid: tid })
+            Ok(Thread { tid })
         };
 
         extern "C" fn thread_start(main: usize) {

std/src/sys/pal/hermit/time.rs

@@ -22,7 +22,7 @@ impl Timespec {
     const fn new(tv_sec: i64, tv_nsec: i32) -> Timespec {
         assert!(tv_nsec >= 0 && tv_nsec < NSEC_PER_SEC);
         // SAFETY: The assert above checks tv_nsec is within the valid range
-        Timespec { t: timespec { tv_sec: tv_sec, tv_nsec: tv_nsec } }
+        Timespec { t: timespec { tv_sec, tv_nsec } }
     }
 
     fn sub_timespec(&self, other: &Timespec) -> Result<Duration, Duration> {

std/src/sys/pal/sgx/fd.rs

@@ -12,7 +12,7 @@ pub struct FileDesc {
 
 impl FileDesc {
     pub fn new(fd: Fd) -> FileDesc {
-        FileDesc { fd: fd }
+        FileDesc { fd }
     }
 
     pub fn raw(&self) -> Fd {