Favor .cast() over as

rust-lang/rust-clippy#8017

Author: taiki-e

futures-task/src/future_obj.rs

@@ -224,7 +224,7 @@ mod if_alloc {
         }
 
         unsafe fn drop(ptr: *mut (dyn Future<Output = T> + 'a)) {
-            drop(Box::from_raw(ptr as *mut F))
+            drop(Box::from_raw(ptr.cast::<F>()))
         }
     }
 

futures-task/src/waker.rs

@@ -20,7 +20,7 @@ pub fn waker<W>(wake: Arc<W>) -> Waker
 where
     W: ArcWake + 'static,
 {
-    let ptr = Arc::into_raw(wake) as *const ();
+    let ptr = Arc::into_raw(wake).cast::<()>();
 
     unsafe { Waker::from_raw(RawWaker::new(ptr, waker_vtable::<W>())) }
 }
@@ -31,7 +31,7 @@ where
 #[allow(clippy::redundant_clone)] // The clone here isn't actually redundant.
 unsafe fn increase_refcount<T: ArcWake>(data: *const ()) {
     // Retain Arc, but don't touch refcount by wrapping in ManuallyDrop
-    let arc = mem::ManuallyDrop::new(Arc::<T>::from_raw(data as *const T));
+    let arc = mem::ManuallyDrop::new(Arc::<T>::from_raw(data.cast::<T>()));
     // Now increase refcount, but don't drop new refcount either
     let _arc_clone: mem::ManuallyDrop<_> = arc.clone();
 }
@@ -43,17 +43,17 @@ unsafe fn clone_arc_raw<T: ArcWake>(data: *const ()) -> RawWaker {
 }
 
 unsafe fn wake_arc_raw<T: ArcWake>(data: *const ()) {
-    let arc: Arc<T> = Arc::from_raw(data as *const T);
+    let arc: Arc<T> = Arc::from_raw(data.cast::<T>());
     ArcWake::wake(arc);
 }
 
 // used by `waker_ref`
 unsafe fn wake_by_ref_arc_raw<T: ArcWake>(data: *const ()) {
     // Retain Arc, but don't touch refcount by wrapping in ManuallyDrop
-    let arc = mem::ManuallyDrop::new(Arc::<T>::from_raw(data as *const T));
+    let arc = mem::ManuallyDrop::new(Arc::<T>::from_raw(data.cast::<T>()));
     ArcWake::wake_by_ref(&arc);
 }
 
 unsafe fn drop_arc_raw<T: ArcWake>(data: *const ()) {
-    drop(Arc::<T>::from_raw(data as *const T))
+    drop(Arc::<T>::from_raw(data.cast::<T>()))
 }