From 52694034ba0e3261fb53c97ca4da7743db4945e7 Mon Sep 17 00:00:00 2001
From: Jason Newcomb <jsnewcomb@pm.me>
Date: Sun, 2 Mar 2025 02:23:14 -0500
Subject: [PATCH] Add `copy_within` to `IndexSlice`

---
 compiler/rustc_index/src/slice.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_index/src/slice.rs b/compiler/rustc_index/src/slice.rs
index 67ac805c2bf..d2702bdb057 100644
--- a/compiler/rustc_index/src/slice.rs
+++ b/compiler/rustc_index/src/slice.rs
@@ -1,6 +1,6 @@
 use std::fmt;
 use std::marker::PhantomData;
-use std::ops::{Index, IndexMut};
+use std::ops::{Index, IndexMut, RangeBounds};
 use std::slice::GetDisjointMutError::*;
 use std::slice::{self, SliceIndex};
 
@@ -104,6 +104,17 @@ impl<I: Idx, T> IndexSlice<I, T> {
         self.raw.swap(a.index(), b.index())
     }
 
+    #[inline]
+    pub fn copy_within(
+        &mut self,
+        src: impl IntoSliceIdx<I, [T], Output: RangeBounds<usize>>,
+        dest: I,
+    ) where
+        T: Copy,
+    {
+        self.raw.copy_within(src.into_slice_idx(), dest.index());
+    }
+
     #[inline]
     pub fn get<R: IntoSliceIdx<I, [T]>>(
         &self,