From ef24de24a82fe681581cc130f342363c47c0969a Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Fri, 7 Jun 2024 07:48:48 +0200
Subject: Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 library/core/src/array/iter.rs | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

(limited to 'library/core/src/array')

diff --git a/library/core/src/array/iter.rs b/library/core/src/array/iter.rs
index 587877dff..321357a15 100644
--- a/library/core/src/array/iter.rs
+++ b/library/core/src/array/iter.rs
@@ -4,7 +4,7 @@ use crate::num::NonZeroUsize;
 use crate::{
     fmt,
     intrinsics::transmute_unchecked,
-    iter::{self, ExactSizeIterator, FusedIterator, TrustedLen},
+    iter::{self, ExactSizeIterator, FusedIterator, TrustedLen, TrustedRandomAccessNoCoerce},
     mem::MaybeUninit,
     ops::{IndexRange, Range},
     ptr,
@@ -13,6 +13,7 @@ use crate::{
 /// A by-value [array] iterator.
 #[stable(feature = "array_value_iter", since = "1.51.0")]
 #[rustc_insignificant_dtor]
+#[rustc_diagnostic_item = "ArrayIntoIter"]
 pub struct IntoIter<T, const N: usize> {
     /// This is the array we are iterating over.
     ///
@@ -293,6 +294,12 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> {
 
         NonZeroUsize::new(remaining).map_or(Ok(()), Err)
     }
+
+    #[inline]
+    unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> Self::Item {
+        // SAFETY: The caller must provide an idx that is in bound of the remainder.
+        unsafe { self.data.as_ptr().add(self.alive.start()).add(idx).cast::<T>().read() }
+    }
 }
 
 #[stable(feature = "array_value_iter_impls", since = "1.40.0")]
@@ -374,6 +381,25 @@ impl<T, const N: usize> FusedIterator for IntoIter<T, N> {}
 #[stable(feature = "array_value_iter_impls", since = "1.40.0")]
 unsafe impl<T, const N: usize> TrustedLen for IntoIter<T, N> {}
 
+#[doc(hidden)]
+#[unstable(issue = "none", feature = "std_internals")]
+#[rustc_unsafe_specialization_marker]
+pub trait NonDrop {}
+
+// T: Copy as approximation for !Drop since get_unchecked does not advance self.alive
+// and thus we can't implement drop-handling
+#[unstable(issue = "none", feature = "std_internals")]
+impl<T: Copy> NonDrop for T {}
+
+#[doc(hidden)]
+#[unstable(issue = "none", feature = "std_internals")]
+unsafe impl<T, const N: usize> TrustedRandomAccessNoCoerce for IntoIter<T, N>
+where
+    T: NonDrop,
+{
+    const MAY_HAVE_SIDE_EFFECT: bool = false;
+}
+
 #[stable(feature = "array_value_iter_impls", since = "1.40.0")]
 impl<T: Clone, const N: usize> Clone for IntoIter<T, N> {
     fn clone(&self) -> Self {
-- 
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