From 449326aaad21ad6e0d104d506d6d1e197e6b9719 Mon Sep 17 00:00:00 2001
From: onestacked <chrisi.schrefl@gmail.com>
Date: Fri, 23 Sep 2022 17:53:59 +0200
Subject: [PATCH] Added const Default impls for Arrays and Tuples.

---
 library/core/src/array/mod.rs | 3 ++-
 library/core/src/tuple.rs     | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index 165b9d24d93..36e89a95fd2 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -434,7 +434,8 @@ impl<T: Copy> SpecArrayClone for T {
 macro_rules! array_impl_default {
     {$n:expr, $t:ident $($ts:ident)*} => {
         #[stable(since = "1.4.0", feature = "array_default")]
-        impl<T> Default for [T; $n] where T: Default {
+        #[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+        impl<T> const Default for [T; $n] where T: ~const Default {
             fn default() -> [T; $n] {
                 [$t::default(), $($ts::default()),*]
             }
diff --git a/library/core/src/tuple.rs b/library/core/src/tuple.rs
index aa8a2425bf4..fc91fe468cc 100644
--- a/library/core/src/tuple.rs
+++ b/library/core/src/tuple.rs
@@ -93,7 +93,8 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[stable(feature = "rust1", since = "1.0.0")]
-            impl<$($T:Default),+> Default for ($($T,)+) {
+            #[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+            impl<$($T: ~const Default),+> const Default for ($($T,)+) {
                 #[inline]
                 fn default() -> ($($T,)+) {
                     ($({ let x: $T = Default::default(); x},)+)