From cc0d6345500932e8118ba65e98944a6a3bac3277 Mon Sep 17 00:00:00 2001
From: Ivan Tham <pickfire@riseup.net>
Date: Thu, 2 Jul 2020 12:13:17 +0800
Subject: [PATCH] Liballoc IntoIter limit unsafe to pointer arithmethic

---
 library/alloc/src/vec.rs | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/library/alloc/src/vec.rs b/library/alloc/src/vec.rs
index 2ff82a5dd3f..aefcbf5ad5d 100644
--- a/library/alloc/src/vec.rs
+++ b/library/alloc/src/vec.rs
@@ -2697,25 +2697,21 @@ 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 T, 1) as *mut T;
+        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 T, 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);
+            // Make up a value of this ZST.
+            Some(unsafe { mem::zeroed() })
+        } else {
+            let old = self.ptr;
+            self.ptr = unsafe { self.ptr.offset(1) };
 
-                    Some(ptr::read(old))
-                }
-            }
+            Some(unsafe { ptr::read(old) })
         }
     }