Refactor away from opaque hashes (#5226)

* System.BlockHash

* Fix hash

* Introduce K/V iteration in all _concat maps

Also move across:
- System.Account (blake2_128_concat)
- Balances.Locks (twox_64_concat)
- ElectionsPhragmen.VotesOf (twox_64_concat)
- ElectionsPhragmen.StakeOf (twox_64_concat)
- Identity.IdentityOf (twox_64_concat)
- Identity.SubsOf (twox_64_concat)
- Society.Payouts (twox_64_concat)
- Session.NextKeys (twox_64_concat)
- Identity.SuperOf (blake2_128_concat)
- Session.KeyOwner (blake2_128_concat)
- Society.SuspendedCandidates (twox_64_concat)
- Society.SuspendedMembers (twox_64_concat)
- Society.Vouching (twox_64_concat)
- Society.Strikes (twox_64_concat)
- System.EventTopics
- Balances.Account

* Build fixes

* Ensure migration happens in correct order

* Staking.*

* Vesting.* Offences.*

* Democracy.*

* Babe.* Collective.*

* Grandpa.*

* Assets.* Benchmark.* Contracts.* Elections.* Asset.* Nicks.*

Also introduce real account list

* ImOnline.*

* Treasury.*

* Recovery.*

* Final bits.

* Docs

* Fix one test

* Fix test

* All passing except the UI tests

* Remove linked_map part 1

* Remove linked_map

* Some iterator utils for double maps.

* Remove old migrations

* Introduce tombstone for LinkedMap type

* Migration for genesis hash

* Fix build

* Fix hash

* Rename Map is_linked -> unused, keeping backwards compat (#5256)

* Update frame/balances/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Update frame/elections/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Remove old migration code.

* Update frame/system/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Update bin/node/runtime/src/lib.rs

Co-Authored-By: Shawn Tabrizi <shawntabrizi@gmail.com>

* Fix hash

* fix session migration

* Fix watning

Co-authored-by: Jaco Greeff <jacogr@gmail.com>
Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
Co-authored-by: Robert Habermeier <rphmeier@gmail.com>

substrate/frame/balances/src/lib.rs

@@ -167,7 +167,7 @@ use frame_support::{
 		Currency, OnKilledAccount, OnUnbalanced, TryDrop, StoredMap,
 		WithdrawReason, WithdrawReasons, LockIdentifier, LockableCurrency, ExistenceRequirement,
 		Imbalance, SignedImbalance, ReservableCurrency, Get, ExistenceRequirement::KeepAlive,
-		ExistenceRequirement::AllowDeath, IsDeadAccount, BalanceStatus as Status
+		ExistenceRequirement::AllowDeath, IsDeadAccount, BalanceStatus as Status, MigrateAccount,
 	}
 };
 use sp_runtime::{
@@ -372,11 +372,11 @@ decl_storage! {
 		/// is ever zero, then the entry *MUST* be removed.
 		///
 		/// NOTE: This is only used in the case that this module is used to store balances.
-		pub Account: map hasher(blake2_256) T::AccountId => AccountData<T::Balance>;
+		pub Account: map hasher(blake2_128_concat) T::AccountId => AccountData<T::Balance>;
 
 		/// Any liquidity locks on some account balances.
 		/// NOTE: Should only be accessed when setting, changing and freeing a lock.
-		pub Locks get(fn locks): map hasher(blake2_256) T::AccountId => Vec<BalanceLock<T::Balance>>;
+		pub Locks get(fn locks): map hasher(blake2_128_concat) T::AccountId => Vec<BalanceLock<T::Balance>>;
 
 		/// Storage version of the pallet.
 		///
@@ -531,6 +531,12 @@ decl_module! {
 	}
 }
 
+impl<T: Trait<I>, I: Instance> MigrateAccount<T::AccountId> for Module<T, I> {
+	fn migrate_account(account: &T::AccountId) {
+		Locks::<T, I>::migrate_key_from_blake(account);
+	}
+}
+
 impl<T: Trait<I>, I: Instance> Module<T, I> {
 	// PRIVATE MUTABLES
 
@@ -850,7 +856,7 @@ impl<T: Subtrait<I>, I: Instance> frame_system::Trait for ElevatedTrait<T, I> {
 	type AvailableBlockRatio = T::AvailableBlockRatio;
 	type Version = T::Version;
 	type ModuleToIndex = T::ModuleToIndex;
-	type OnNewAccount = T::OnNewAccount;
+	type MigrateAccount = (); type OnNewAccount = T::OnNewAccount;
 	type OnKilledAccount = T::OnKilledAccount;
 	type AccountData = T::AccountData;
 }

substrate/frame/balances/src/tests_composite.rs

@@ -66,7 +66,7 @@ impl frame_system::Trait for Test {
 	type Version = ();
 	type ModuleToIndex = ();
 	type AccountData = super::AccountData<u64>;
-	type OnNewAccount = ();
+	type MigrateAccount = (); type OnNewAccount = ();
 	type OnKilledAccount = ();
 }
 parameter_types! {

substrate/frame/balances/src/tests_local.rs

@@ -66,7 +66,7 @@ impl frame_system::Trait for Test {
 	type Version = ();
 	type ModuleToIndex = ();
 	type AccountData = super::AccountData<u64>;
-	type OnNewAccount = ();
+	type MigrateAccount = (); type OnNewAccount = ();
 	type OnKilledAccount = Module<Test>;
 }
 parameter_types! {