constify comparison traits on arrays

Author: npmccallum

library/core/src/array/equality.rs

@@ -132,9 +132,8 @@ where
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
 impl<T: [const] Eq, const N: usize> const Eq for [T; N] {}
 
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-trait SpecArrayEq<Other, const N: usize>: Sized {
+const trait SpecArrayEq<Other, const N: usize>: Sized {
     fn spec_eq(a: &[Self; N], b: &[Other; N]) -> bool;
     fn spec_ne(a: &[Self; N], b: &[Other; N]) -> bool;
 }

library/core/src/array/mod.rs

@@ -403,7 +403,8 @@ where
 
 /// Implements comparison of arrays [lexicographically](Ord#lexicographical-comparison).
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: PartialOrd, const N: usize> PartialOrd for [T; N] {
+#[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
+impl<T: [const] PartialOrd, const N: usize> const PartialOrd for [T; N] {
     #[inline]
     fn partial_cmp(&self, other: &[T; N]) -> Option<Ordering> {
         PartialOrd::partial_cmp(&&self[..], &&other[..])
@@ -428,7 +429,8 @@ impl<T: PartialOrd, const N: usize> PartialOrd for [T; N] {
 
 /// Implements comparison of arrays [lexicographically](Ord#lexicographical-comparison).
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: Ord, const N: usize> Ord for [T; N] {
+#[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
+impl<T: [const] Ord, const N: usize> const Ord for [T; N] {
     #[inline]
     fn cmp(&self, other: &[T; N]) -> Ordering {
         Ord::cmp(&&self[..], &&other[..])