Rollup merge of rust-lang#104125 - ink-feather-org:const_cmp_tuples, r=fee1-dead

Const Compare for Tuples

Makes the impls for Tuples of ~const `PartialEq` types also `PartialEq`, impls for Tuples of ~const `PartialOrd` types also `PartialOrd`, for Tuples of ~const `Ord` types also `Ord`.

behind the `#![feature(const_cmp)]` gate.

~~Do not merge before rust-lang#104113 is merged because I want to use this feature to clean up the new test that I added there.~~

r? ``@fee1-dead``

Author: Dylan-DPC

core/src/tuple.rs

@@ -22,7 +22,8 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[stable(feature = "rust1", since = "1.0.0")]
-            impl<$($T:PartialEq),+> PartialEq for ($($T,)+)
+            #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+            impl<$($T: ~const PartialEq),+> const PartialEq for ($($T,)+)
             where
                 last_type!($($T,)+): ?Sized
             {
@@ -40,7 +41,7 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[stable(feature = "rust1", since = "1.0.0")]
-            impl<$($T:Eq),+> Eq for ($($T,)+)
+            impl<$($T: Eq),+> Eq for ($($T,)+)
             where
                 last_type!($($T,)+): ?Sized
             {}
@@ -49,7 +50,8 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[stable(feature = "rust1", since = "1.0.0")]
-            impl<$($T:PartialOrd + PartialEq),+> PartialOrd for ($($T,)+)
+            #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+            impl<$($T: ~const PartialOrd + ~const PartialEq),+> const PartialOrd for ($($T,)+)
             where
                 last_type!($($T,)+): ?Sized
             {
@@ -79,7 +81,8 @@ macro_rules! tuple_impls {
         maybe_tuple_doc! {
             $($T)+ @
             #[stable(feature = "rust1", since = "1.0.0")]
-            impl<$($T:Ord),+> Ord for ($($T,)+)
+            #[rustc_const_unstable(feature = "const_cmp", issue = "92391")]
+            impl<$($T: ~const Ord),+> const Ord for ($($T,)+)
             where
                 last_type!($($T,)+): ?Sized
             {