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/vesting/src/lib.rs

@@ -53,10 +53,7 @@ use sp_runtime::{DispatchResult, RuntimeDebug, traits::{
 	StaticLookup, Zero, AtLeast32Bit, MaybeSerializeDeserialize, Convert
 }};
 use frame_support::{decl_module, decl_event, decl_storage, decl_error, ensure};
-use frame_support::traits::{
-	Currency, LockableCurrency, VestingSchedule, WithdrawReason, LockIdentifier, ExistenceRequirement,
-	Get,
-};
+use frame_support::traits::{Currency, LockableCurrency, VestingSchedule, WithdrawReason, LockIdentifier, ExistenceRequirement, Get, MigrateAccount};
 use frame_support::weights::SimpleDispatchInfo;
 use frame_system::{self as system, ensure_signed};
 
@@ -118,7 +115,8 @@ decl_storage! {
 	trait Store for Module<T: Trait> as Vesting {
 		/// Information regarding the vesting of a given account.
 		pub Vesting get(fn vesting):
-			map hasher(blake2_256) T::AccountId => Option<VestingInfo<BalanceOf<T>, T::BlockNumber>>;
+			map hasher(blake2_128_concat) T::AccountId
+			=> Option<VestingInfo<BalanceOf<T>, T::BlockNumber>>;
 	}
 	add_extra_genesis {
 		config(vesting): Vec<(T::AccountId, T::BlockNumber, T::BlockNumber, BalanceOf<T>)>;
@@ -256,6 +254,12 @@ decl_module! {
 	}
 }
 
+impl<T: Trait> MigrateAccount<T::AccountId> for Module<T> {
+	fn migrate_account(a: &T::AccountId) {
+		Vesting::<T>::migrate_key_from_blake(a);
+	}
+}
+
 impl<T: Trait> Module<T> {
 	/// (Re)set or remove the module's currency lock on `who`'s account in accordance with their
 	/// current unvested amount.
@@ -384,7 +388,7 @@ mod tests {
 		type Version = ();
 		type ModuleToIndex = ();
 		type AccountData = pallet_balances::AccountData<u64>;
-		type OnNewAccount = ();
+		type MigrateAccount = (); type OnNewAccount = ();
 		type OnKilledAccount = ();
 	}
 	impl pallet_balances::Trait for Test {