Auto merge of #73951 - pickfire:liballoc-intoiter, r=Mark-Simulacrum

Liballoc intoiter refactor

Author: bors

library/alloc/src/vec.rs

@@ -2882,25 +2882,21 @@ impl<T> Iterator for IntoIter<T> {
 
  #[inline]
  fn next(&mut self) -> Option<T> {
- unsafe {
- if self.ptr as *const _ == self.end {
- None
- } else {
- if mem::size_of::<T>() == 0 {
- // purposefully don't use 'ptr.offset' because for
- // vectors with 0-size elements this would return the
- // same pointer.
- self.ptr = arith_offset(self.ptr as *const i8, 1) as *mut T;
-
- // Make up a value of this ZST.
- Some(mem::zeroed())
- } else {
- let old = self.ptr;
- self.ptr = self.ptr.offset(1);
-
- Some(ptr::read(old))
- }
- }
+ if self.ptr as *const _ == self.end {
+ None
+ } else if mem::size_of::<T>() == 0 {
+ // purposefully don't use 'ptr.offset' because for
+ // vectors with 0-size elements this would return the
+ // same pointer.
+ self.ptr = unsafe { arith_offset(self.ptr as *const i8, 1) as *mut T };
+
+ // Make up a value of this ZST.
+ Some(unsafe { mem::zeroed() })
+ } else {
+ let old = self.ptr;
+ self.ptr = unsafe { self.ptr.offset(1) };
+
+ Some(unsafe { ptr::read(old) })
  }
  }
 
@@ -2935,22 +2931,18 @@ impl<T> Iterator for IntoIter<T> {
 impl<T> DoubleEndedIterator for IntoIter<T> {
  #[inline]
  fn next_back(&mut self) -> Option<T> {
- unsafe {
- if self.end == self.ptr {
- None
- } else {
- if mem::size_of::<T>() == 0 {
- // See above for why 'ptr.offset' isn't used
- self.end = arith_offset(self.end as *const i8, -1) as *mut T;
+ if self.end == self.ptr {
+ None
+ } else if mem::size_of::<T>() == 0 {
+ // See above for why 'ptr.offset' isn't used
+ self.end = unsafe { arith_offset(self.end as *const i8, -1) as *mut T };
 
-  // Make up a value of this ZST.
-  Some(mem::zeroed())
-  } else {
-  self.end = self.end.offset(-1);
+ // Make up a value of this ZST.
+ Some(unsafe { mem::zeroed() })
+ } else {
+ self.end = unsafe { self.end.offset(-1) };
 
- Some(ptr::read(self.end))
- }
- }
+ Some(unsafe { ptr::read(self.end) })
  }
  }
 }