From: Giacomo Stevanato <giaco.stevanato@gmail.com>
Date: Wed, 20 Oct 2021 13:42:54 +0000 (+0200)
Subject: Prevent invalid values from existing in Vec::swap_remove
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=0aa68a8db9dfffb2756279cc621b1b15a896423d;hp=6162529a01473bbb2427fa27354cbafc3c514eee;p=rust.git

Prevent invalid values from existing in Vec::swap_remove
---

diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index 20a16869cb3..d52c78eedf3 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1305,10 +1305,11 @@ fn assert_failed(index: usize, len: usize) -> ! {
             // We replace self[index] with the last element. Note that if the
             // bounds check above succeeds there must be a last element (which
             // can be self[index] itself).
-            let last = ptr::read(self.as_ptr().add(len - 1));
-            let hole = self.as_mut_ptr().add(index);
+            let value = ptr::read(self.as_ptr().add(index));
+            let base_ptr = self.as_mut_ptr();
+            ptr::copy(base_ptr.add(len - 1), base_ptr.add(index), 1);
             self.set_len(len - 1);
-            ptr::replace(hole, last)
+            value
         }
     }