From 55def120a4d54123625ad05c4d6384c5044642f1 Mon Sep 17 00:00:00 2001
From: The8472 <git@infinite-source.de>
Date: Thu, 5 Aug 2021 19:52:08 +0200
Subject: [PATCH] replace Vec<u8> with Box<[u8]>

---
 compiler/rustc_middle/src/mir/interpret/allocation.rs | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs
index ada6e097766..5964efa78e9 100644
--- a/compiler/rustc_middle/src/mir/interpret/allocation.rs
+++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs
@@ -28,7 +28,7 @@ use crate::ty;
 pub struct Allocation<Tag = AllocId, Extra = ()> {
     /// The actual bytes of the allocation.
     /// Note that the bytes of a pointer represent the offset of the pointer.
-    bytes: Vec<u8>,
+    bytes: Box<[u8]>,
     /// Maps from byte addresses to extra data for each pointer.
     /// Only the first byte of a pointer is inserted into the map; i.e.,
     /// every entry in this map applies to `pointer_size` consecutive bytes starting
@@ -112,7 +112,7 @@ impl<Tag> Allocation<Tag> {
         align: Align,
         mutability: Mutability,
     ) -> Self {
-        let bytes = slice.into().into_owned();
+        let bytes = Box::<[u8]>::from(slice.into());
         let size = Size::from_bytes(bytes.len());
         Self {
             bytes,
@@ -145,9 +145,8 @@ impl<Tag> Allocation<Tag> {
             });
             InterpError::ResourceExhaustion(ResourceExhaustionInfo::MemoryExhausted)
         })?;
-        // SAFETY: This turns a Box<[MaybeUninit<u8>]> into a Vec<u8>. This is safe since the box
-        // was zero-allocated which is a valid value for u8.
-        let bytes = unsafe { bytes.assume_init().into_vec() };
+        // SAFETY: the box was zero-allocated, which is a valid initial value for Box<[u8]>
+        let bytes = unsafe { bytes.assume_init() };
         Ok(Allocation {
             bytes,
             relocations: Relocations::new(),