Cleanup our sort usage (#6754)

substrate/frame/collective/src/lib.rs

@@ -893,7 +893,7 @@ impl<T: Trait<I>, I: Instance> ChangeMembers<T::AccountId> for Module<T, I> {
 		}
 		// remove accounts from all current voting in motions.
 		let mut outgoing = outgoing.to_vec();
-		outgoing.sort_unstable();
+		outgoing.sort();
 		for h in Self::proposals().into_iter() {
 			<Voting<T, I>>::mutate(h, |v|
 				if let Some(mut votes) = v.take() {

substrate/frame/contracts/src/wasm/runtime.rs

@@ -1211,7 +1211,7 @@ where
 /// the order of items is not preserved.
 fn has_duplicates<T: PartialEq + AsRef<[u8]>>(items: &mut Vec<T>) -> bool {
 	// Sort the vector
-	items.sort_unstable_by(|a, b| {
+	items.sort_by(|a, b| {
 		Ord::cmp(a.as_ref(), b.as_ref())
 	});
 	// And then find any two consecutive equal elements.

substrate/frame/staking/src/lib.rs

@@ -1238,12 +1238,12 @@ decl_storage! {
 decl_event!(
 	pub enum Event<T> where Balance = BalanceOf<T>, <T as frame_system::Trait>::AccountId {
 		/// The era payout has been set; the first balance is the validator-payout; the second is
-		/// the remainder from the maximum amount of reward. 
+		/// the remainder from the maximum amount of reward.
 		/// [era_index, validator_payout, remainder]
 		EraPayout(EraIndex, Balance, Balance),
 		/// The staker has been rewarded by this amount. [stash, amount]
 		Reward(AccountId, Balance),
-		/// One validator (and its nominators) has been slashed by the given amount. 
+		/// One validator (and its nominators) has been slashed by the given amount.
 		/// [validator, amount]
 		Slash(AccountId, Balance),
 		/// An old slashing report from a prior era was discarded because it could
@@ -2889,7 +2889,7 @@ impl<T: Trait> Module<T> {
 				let mut exposure_clipped = exposure;
 				let clipped_max_len = T::MaxNominatorRewardedPerValidator::get() as usize;
 				if exposure_clipped.others.len() > clipped_max_len {
-					exposure_clipped.others.sort_unstable_by(|a, b| a.value.cmp(&b.value).reverse());
+					exposure_clipped.others.sort_by(|a, b| a.value.cmp(&b.value).reverse());
 					exposure_clipped.others.truncate(clipped_max_len);
 				}
 				<ErasStakersClipped<T>>::insert(&current_era, &stash, exposure_clipped);

substrate/frame/support/src/traits.rs

@@ -1238,7 +1238,7 @@ pub trait ChangeMembers<AccountId: Clone + Ord> {
 	///
 	/// This resets any previous value of prime.
 	fn change_members(incoming: &[AccountId], outgoing: &[AccountId], mut new: Vec<AccountId>) {
-		new.sort_unstable();
+		new.sort();
 		Self::change_members_sorted(incoming, outgoing, &new[..]);
 	}