From 51edc219906f0973dd66b4b6ff5ff0ac857a4cc6 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Wed, 20 Sep 2023 07:36:19 +1000
Subject: [PATCH] Remove `unsafe` from `TypedArena::alloc_raw_slice`.

There's no good reason for it.
---
 compiler/rustc_arena/src/lib.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/compiler/rustc_arena/src/lib.rs b/compiler/rustc_arena/src/lib.rs
index a8a4ad89c4f..5c183afc087 100644
--- a/compiler/rustc_arena/src/lib.rs
+++ b/compiler/rustc_arena/src/lib.rs
@@ -172,8 +172,8 @@ impl<T, const N: usize> IterExt<T> for std::array::IntoIter<T, N> {
             return &mut [];
         }
         // Move the content to the arena by copying and then forgetting it.
+        let start_ptr = arena.alloc_raw_slice(len);
         unsafe {
-            let start_ptr = arena.alloc_raw_slice(len);
             self.as_slice().as_ptr().copy_to_nonoverlapping(start_ptr, len);
             mem::forget(self);
             slice::from_raw_parts_mut(start_ptr, len)
@@ -189,8 +189,8 @@ impl<T> IterExt<T> for Vec<T> {
             return &mut [];
         }
         // Move the content to the arena by copying and then forgetting it.
+        let start_ptr = arena.alloc_raw_slice(len);
         unsafe {
-            let start_ptr = arena.alloc_raw_slice(len);
             self.as_ptr().copy_to_nonoverlapping(start_ptr, len);
             self.set_len(0);
             slice::from_raw_parts_mut(start_ptr, len)
@@ -206,8 +206,8 @@ impl<A: smallvec::Array> IterExt<A::Item> for SmallVec<A> {
             return &mut [];
         }
         // Move the content to the arena by copying and then forgetting it.
+        let start_ptr = arena.alloc_raw_slice(len);
         unsafe {
-            let start_ptr = arena.alloc_raw_slice(len);
             self.as_ptr().copy_to_nonoverlapping(start_ptr, len);
             self.set_len(0);
             slice::from_raw_parts_mut(start_ptr, len)
@@ -251,7 +251,7 @@ impl<T> TypedArena<T> {
     }
 
     #[inline]
-    unsafe fn alloc_raw_slice(&self, len: usize) -> *mut T {
+    fn alloc_raw_slice(&self, len: usize) -> *mut T {
         assert!(mem::size_of::<T>() != 0);
         assert!(len != 0);