From: Ralf Jung <post@ralfj.de>
Date: Sat, 29 Feb 2020 13:07:20 +0000 (+0100)
Subject: clarify alignment requirements in Vec::from_raw_parts
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=0edc90cd1884c945b00512d2dede33c8a725ceb4;p=rust.git

clarify alignment requirements in Vec::from_raw_parts
---

diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index 29987ac44e6..fc50d06b33c 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -404,7 +404,10 @@ pub fn into_raw_parts(self) -> (*mut T, usize, usize) {
     ///
     /// * `ptr` needs to have been previously allocated via [`String`]/`Vec<T>`
     ///   (at least, it's highly likely to be incorrect if it wasn't).
-    /// * `ptr`'s `T` needs to have the same size and alignment as it was allocated with.
+    /// * `T` needs to have the same size and alignment as what `ptr` was allocated with.
+    ///   (`T` having a less strict alignment is not sufficient, the alignment really
+    ///   needs to be equal to satsify the [`dealloc`] requirement that memory must be
+    ///   allocated and deallocated with the same layout.)
     /// * `length` needs to be less than or equal to `capacity`.
     /// * `capacity` needs to be the capacity that the pointer was allocated with.
     ///
@@ -423,6 +426,7 @@ pub fn into_raw_parts(self) -> (*mut T, usize, usize) {
     /// function.
     ///
     /// [`String`]: ../../std/string/struct.String.html
+    /// [`dealloc`]: ../../alloc/alloc/trait.GlobalAlloc.html#tymethod.dealloc
     ///
     /// # Examples
     ///