From f9e3e0d3a0732dc5210e5c46053b99ad05cfcb94 Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Tue, 3 Oct 2023 15:24:19 +0200
Subject: [PATCH 01/11] trait bound balance

---
 .../runtime/common/src/assigned_slots/mod.rs  |  5 +-
 polkadot/runtime/common/src/auctions.rs       |  8 ++-
 polkadot/runtime/common/src/slots/mod.rs      | 70 +++++++++++++------
 polkadot/runtime/common/src/traits.rs         | 14 ++--
 4 files changed, 67 insertions(+), 30 deletions(-)

diff --git a/polkadot/runtime/common/src/assigned_slots/mod.rs b/polkadot/runtime/common/src/assigned_slots/mod.rs
index cc8ec339c1184..a02a6029cce96 100644
--- a/polkadot/runtime/common/src/assigned_slots/mod.rs
+++ b/polkadot/runtime/common/src/assigned_slots/mod.rs
@@ -30,7 +30,7 @@ use crate::{
 	slots::{self, Pallet as Slots, WeightInfo as SlotsWeightInfo},
 	traits::{LeaseError, Leaser, Registrar},
 };
-use frame_support::{pallet_prelude::*, traits::Currency};
+use frame_support::{pallet_prelude::*, traits::{Currency, fungible::Inspect as FunInspect}};
 use frame_system::pallet_prelude::*;
 pub use pallet::*;
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
@@ -98,9 +98,10 @@ impl WeightInfo for TestWeightInfo {
 	}
 }
 
-type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as Currency<
+type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
 	<T as frame_system::Config>::AccountId,
 >>::Balance;
+
 type LeasePeriodOf<T> = <<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::LeasePeriod;
 
 #[frame_support::pallet]
diff --git a/polkadot/runtime/common/src/auctions.rs b/polkadot/runtime/common/src/auctions.rs
index e35303912fa1d..5d5b7bef19df9 100644
--- a/polkadot/runtime/common/src/auctions.rs
+++ b/polkadot/runtime/common/src/auctions.rs
@@ -25,7 +25,7 @@ use crate::{
 use frame_support::{
 	dispatch::DispatchResult,
 	ensure,
-	traits::{Currency, Get, Randomness, ReservableCurrency},
+	traits::{{Currency, Get, Randomness, ReservableCurrency}, fungible::Inspect as FunInspect},
 	weights::Weight,
 };
 use frame_system::pallet_prelude::BlockNumberFor;
@@ -35,8 +35,8 @@ use primitives::Id as ParaId;
 use sp_runtime::traits::{CheckedSub, One, Saturating, Zero};
 use sp_std::{mem::swap, prelude::*};
 
-type CurrencyOf<T> = <<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency;
-type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as Currency<
+type CurrencyOf<T> = <T as Config>::Currency;
+type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
 	<T as frame_system::Config>::AccountId,
 >>::Balance;
 
@@ -98,6 +98,8 @@ pub mod pallet {
 			LeasePeriod = BlockNumberFor<Self>,
 		>;
 
+		type Currency: ReservableCurrency<Self::AccountId, Balance = <<Self::Leaser as Leaser<BlockNumberFor<Self>>>::Currency as FunInspect<Self::AccountId>>::Balance>;
+
 		/// The parachain registrar type.
 		type Registrar: Registrar<AccountId = Self::AccountId>;
 
diff --git a/polkadot/runtime/common/src/slots/mod.rs b/polkadot/runtime/common/src/slots/mod.rs
index a3efd5bfa30a6..c6276fcfe1b27 100644
--- a/polkadot/runtime/common/src/slots/mod.rs
+++ b/polkadot/runtime/common/src/slots/mod.rs
@@ -26,8 +26,12 @@ pub mod migration;
 
 use crate::traits::{LeaseError, Leaser, Registrar};
 use frame_support::{
+	defensive_assert,
 	pallet_prelude::*,
-	traits::{Currency, ReservableCurrency},
+	traits::fungible::{
+		hold::{Inspect as FunHoldInspect, Mutate as FunHoldMutate},
+		Inspect as FunInspect, Mutate as FunMutate,
+	},
 	weights::Weight,
 };
 use frame_system::pallet_prelude::*;
@@ -37,7 +41,8 @@ use sp_runtime::traits::{CheckedConversion, CheckedSub, Saturating, Zero};
 use sp_std::prelude::*;
 
 type BalanceOf<T> =
-	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
+	<<T as Config>::Currency as FunInspect<<T as frame_system::Config>::AccountId>>::Balance;
+
 type LeasePeriodOf<T> = BlockNumberFor<T>;
 
 pub trait WeightInfo {
@@ -77,7 +82,10 @@ pub mod pallet {
 		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
 
 		/// The currency type used for bidding.
-		type Currency: ReservableCurrency<Self::AccountId>;
+		type Currency: FunHoldMutate<Self::AccountId, Reason = Self::RuntimeHoldReason>;
+
+		/// The hold reason when reserving funds for the lease.
+		type RuntimeHoldReason: From<HoldReason>;
 
 		/// The parachain registrar type.
 		type Registrar: Registrar<AccountId = Self::AccountId>;
@@ -144,6 +152,14 @@ pub mod pallet {
 		LeaseError,
 	}
 
+	/// A reason for the pallet placing a hold on funds.
+	#[pallet::composite_enum]
+	pub enum HoldReason {
+		/// Funds are held for the current or upcoming leases.
+		#[codec(index = 0)]
+		LeaseDeposit,
+	}
+
 	#[pallet::hooks]
 	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
 		fn on_initialize(n: BlockNumberFor<T>) -> Weight {
@@ -192,8 +208,7 @@ pub mod pallet {
 
 			// Refund any deposits for these leases
 			for (who, deposit) in deposits {
-				let err_amount = T::Currency::unreserve(&who, deposit);
-				debug_assert!(err_amount.is_zero());
+				Self::release(&who, deposit);
 			}
 
 			Leases::<T>::remove(para);
@@ -247,9 +262,9 @@ impl<T: Config> Pallet<T> {
 				//
 				// `para` is now just an on-demand parachain.
 				//
-				// Unreserve whatever is left.
+				// Release whatever is left.
 				if let Some((who, value)) = &lease_periods[0] {
-					T::Currency::unreserve(&who, *value);
+					Self::release(&who, *value);
 				}
 
 				// Remove the now-empty lease list.
@@ -270,9 +285,9 @@ impl<T: Config> Pallet<T> {
 					let now_held = Self::deposit_held(para, &ended_lease.0);
 
 					// If this is less than what we were holding for this leaser's now-ended lease,
-					// then unreserve it.
+					// then release it.
 					if let Some(rebate) = ended_lease.1.checked_sub(&now_held) {
-						T::Currency::unreserve(&ended_lease.0, rebate);
+						Self::release(&ended_lease.0, rebate);
 					}
 				}
 
@@ -308,7 +323,7 @@ impl<T: Config> Pallet<T> {
 
 	// Return a vector of (user, balance) for all deposits for a parachain.
 	// Useful when trying to clean up a parachain leases, as this would tell
-	// you all the balances you need to unreserve.
+	// you all the balances you need to release.
 	fn all_deposits_held(para: ParaId) -> Vec<(T::AccountId, BalanceOf<T>)> {
 		let mut tracker = sp_std::collections::btree_map::BTreeMap::new();
 		Leases::<T>::get(para).into_iter().for_each(|lease| match lease {
@@ -326,6 +341,21 @@ impl<T: Config> Pallet<T> {
 
 		tracker.into_iter().collect()
 	}
+
+	fn hold(leaser: &T::AccountId, amount: BalanceOf<T>) -> DispatchResult {
+		T::Currency::hold(&HoldReason::LeaseDeposit.into(), leaser, amount)
+	}
+
+	fn release(leaser: &T::AccountId, amount: BalanceOf<T>) {
+		let amount = T::Currency::release(
+			&HoldReason::LeaseDeposit.into(),
+			&leaser,
+			amount,
+			frame_support::traits::tokens::Precision::BestEffort,
+		);
+
+		defensive_assert!(amount.is_ok() && amount.unwrap() == amount);
+	}
 }
 
 impl<T: Config> crate::traits::OnSwap for Pallet<T> {
@@ -342,7 +372,7 @@ impl<T: Config> Leaser<BlockNumberFor<T>> for Pallet<T> {
 	fn lease_out(
 		para: ParaId,
 		leaser: &Self::AccountId,
-		amount: <Self::Currency as Currency<Self::AccountId>>::Balance,
+		amount: BalanceOf<T>,
 		period_begin: Self::LeasePeriod,
 		period_count: Self::LeasePeriod,
 	) -> Result<(), LeaseError> {
@@ -397,8 +427,7 @@ impl<T: Config> Leaser<BlockNumberFor<T>> for Pallet<T> {
 			// `para_id`.  If so, then we can deduct those from the amount that we need to reserve.
 			let maybe_additional = amount.checked_sub(&Self::deposit_held(para, &leaser));
 			if let Some(ref additional) = maybe_additional {
-				T::Currency::reserve(&leaser, *additional)
-					.map_err(|_| LeaseError::ReserveFailed)?;
+				Self::hold(&leaser, *additional).map_err(|_| LeaseError::ReserveFailed)?;
 			}
 
 			let reserved = maybe_additional.unwrap_or_default();
@@ -424,10 +453,7 @@ impl<T: Config> Leaser<BlockNumberFor<T>> for Pallet<T> {
 		})
 	}
 
-	fn deposit_held(
-		para: ParaId,
-		leaser: &Self::AccountId,
-	) -> <Self::Currency as Currency<Self::AccountId>>::Balance {
+	fn deposit_held(para: ParaId, leaser: &Self::AccountId) -> BalanceOf<T> {
 		Leases::<T>::get(para)
 			.into_iter()
 			.map(|lease| match lease {
@@ -584,6 +610,7 @@ mod tests {
 	impl Config for Test {
 		type RuntimeEvent = RuntimeEvent;
 		type Currency = Balances;
+		type RuntimeHoldReason = RuntimeHoldReason;
 		type Registrar = TestRegistrar<Test>;
 		type LeasePeriod = LeasePeriod;
 		type LeaseOffset = LeaseOffset;
@@ -1008,7 +1035,7 @@ mod benchmarking {
 	fn register_a_parathread<T: Config + paras::Config>(i: u32) -> (ParaId, T::AccountId) {
 		let para = ParaId::from(i);
 		let leaser: T::AccountId = account("leaser", i, 0);
-		T::Currency::make_free_balance_be(&leaser, BalanceOf::<T>::max_value());
+		T::Currency::set_balance(&leaser, BalanceOf::<T>::max_value());
 		let worst_head_data = T::Registrar::worst_head_data();
 		let worst_validation_code = T::Registrar::worst_validation_code();
 
@@ -1036,7 +1063,7 @@ mod benchmarking {
 			frame_system::Pallet::<T>::set_block_number(T::LeaseOffset::get() + One::one());
 			let para = ParaId::from(1337);
 			let leaser: T::AccountId = account("leaser", 0, 0);
-			T::Currency::make_free_balance_be(&leaser, BalanceOf::<T>::max_value());
+			T::Currency::set_balance(&leaser, BalanceOf::<T>::max_value());
 			let amount = T::Currency::minimum_balance();
 			let period_begin = 69u32.into();
 			let period_count = 3u32.into();
@@ -1122,7 +1149,7 @@ mod benchmarking {
 			for i in 0 .. max_people {
 				let leaser = account("lease_deposit", i, 0);
 				let amount = T::Currency::minimum_balance();
-				T::Currency::make_free_balance_be(&leaser, BalanceOf::<T>::max_value());
+				T::Currency::set_balance(&leaser, BalanceOf::<T>::max_value());
 
 				// Average slot has 4 lease periods.
 				let period_count: LeasePeriodOf<T> = 4u32.into();
@@ -1134,7 +1161,7 @@ mod benchmarking {
 
 			for i in 0 .. max_people {
 				let leaser = account("lease_deposit", i, 0);
-				assert_eq!(T::Currency::reserved_balance(&leaser), T::Currency::minimum_balance());
+				assert_eq!(T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into, &leaser), T::Currency::minimum_balance());
 			}
 
 			let origin =
@@ -1143,6 +1170,7 @@ mod benchmarking {
 		verify {
 			for i in 0 .. max_people {
 				let leaser = account("lease_deposit", i, 0);
+				assert_eq!(T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into, &leaser), 0u32.into());
 				assert_eq!(T::Currency::reserved_balance(&leaser), 0u32.into());
 			}
 		}
diff --git a/polkadot/runtime/common/src/traits.rs b/polkadot/runtime/common/src/traits.rs
index 8f75bf5c2fd83..8fa23fcdf53c1 100644
--- a/polkadot/runtime/common/src/traits.rs
+++ b/polkadot/runtime/common/src/traits.rs
@@ -18,7 +18,13 @@
 
 use frame_support::{
 	dispatch::DispatchResult,
-	traits::{Currency, ReservableCurrency},
+	traits::{
+		fungible::{
+			hold::{Inspect as FunHoldInspect, Mutate as FunHoldMutate},
+			Inspect as FunInspect, Mutate as FunMutate,
+		},
+		Currency, ReservableCurrency,
+	},
 };
 use primitives::{HeadData, Id as ParaId, ValidationCode};
 use sp_std::vec::*;
@@ -109,7 +115,7 @@ pub trait Leaser<BlockNumber> {
 	type LeasePeriod;
 
 	/// The currency type in which the lease is taken.
-	type Currency: ReservableCurrency<Self::AccountId>;
+	type Currency: FunHoldMutate<Self::AccountId>;
 
 	/// Lease a new parachain slot for `para`.
 	///
@@ -126,7 +132,7 @@ pub trait Leaser<BlockNumber> {
 	fn lease_out(
 		para: ParaId,
 		leaser: &Self::AccountId,
-		amount: <Self::Currency as Currency<Self::AccountId>>::Balance,
+		amount: <Self::Currency as FunInspect<Self::AccountId>>::Balance,
 		period_begin: Self::LeasePeriod,
 		period_count: Self::LeasePeriod,
 	) -> Result<(), LeaseError>;
@@ -136,7 +142,7 @@ pub trait Leaser<BlockNumber> {
 	fn deposit_held(
 		para: ParaId,
 		leaser: &Self::AccountId,
-	) -> <Self::Currency as Currency<Self::AccountId>>::Balance;
+	) -> <Self::Currency as FunInspect<Self::AccountId>>::Balance;
 
 	/// The length of a lease period, and any offset which may be introduced.
 	/// This is only used in benchmarking to automate certain calls.

From 624c3f4aa9106989c9e6cd6daf2817a301fcb907 Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Wed, 4 Oct 2023 04:39:41 +0200
Subject: [PATCH 02/11] everything compiles

---
 polkadot/runtime/common/src/assigned_slots/mod.rs | 3 ++-
 polkadot/runtime/common/src/auctions.rs           | 1 +
 polkadot/runtime/common/src/integration_tests.rs  | 4 +++-
 polkadot/runtime/common/src/slots/mod.rs          | 6 +++---
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/polkadot/runtime/common/src/assigned_slots/mod.rs b/polkadot/runtime/common/src/assigned_slots/mod.rs
index a02a6029cce96..bd1bdda1afde6 100644
--- a/polkadot/runtime/common/src/assigned_slots/mod.rs
+++ b/polkadot/runtime/common/src/assigned_slots/mod.rs
@@ -664,7 +664,7 @@ mod tests {
 			Configuration: parachains_configuration::{Pallet, Call, Storage, Config<T>},
 			ParasShared: parachains_shared::{Pallet, Call, Storage},
 			Parachains: parachains_paras::{Pallet, Call, Storage, Config<T>, Event},
-			Slots: slots::{Pallet, Call, Storage, Event<T>},
+			Slots: slots::{Pallet, Call, Storage, Event<T>, HoldReason},
 			AssignedSlots: assigned_slots::{Pallet, Call, Storage, Event<T>},
 		}
 	);
@@ -754,6 +754,7 @@ mod tests {
 	impl slots::Config for Test {
 		type RuntimeEvent = RuntimeEvent;
 		type Currency = Balances;
+		type RuntimeHoldReason = RuntimeHoldReason;
 		type Registrar = TestRegistrar<Test>;
 		type LeasePeriod = LeasePeriod;
 		type LeaseOffset = LeaseOffset;
diff --git a/polkadot/runtime/common/src/auctions.rs b/polkadot/runtime/common/src/auctions.rs
index 5d5b7bef19df9..2a937c7322e21 100644
--- a/polkadot/runtime/common/src/auctions.rs
+++ b/polkadot/runtime/common/src/auctions.rs
@@ -875,6 +875,7 @@ mod tests {
 	impl Config for Test {
 		type RuntimeEvent = RuntimeEvent;
 		type Leaser = TestLeaser;
+		type Currency = Balances;
 		type Registrar = TestRegistrar<Self>;
 		type EndingPeriod = EndingPeriod;
 		type SampleLength = SampleLength;
diff --git a/polkadot/runtime/common/src/integration_tests.rs b/polkadot/runtime/common/src/integration_tests.rs
index f14db68267d5b..3560f3481a01d 100644
--- a/polkadot/runtime/common/src/integration_tests.rs
+++ b/polkadot/runtime/common/src/integration_tests.rs
@@ -87,7 +87,7 @@ frame_support::construct_runtime!(
 		Registrar: paras_registrar::{Pallet, Call, Storage, Event<T>},
 		Auctions: auctions::{Pallet, Call, Storage, Event<T>},
 		Crowdloan: crowdloan::{Pallet, Call, Storage, Event<T>},
-		Slots: slots::{Pallet, Call, Storage, Event<T>},
+		Slots: slots::{Pallet, Call, Storage, Event<T>, HoldReason},
 	}
 );
 
@@ -230,6 +230,7 @@ parameter_types! {
 impl auctions::Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type Leaser = Slots;
+	type Currency = Balances;
 	type Registrar = Registrar;
 	type EndingPeriod = EndingPeriod;
 	type SampleLength = SampleLength;
@@ -246,6 +247,7 @@ parameter_types! {
 impl slots::Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type Currency = Balances;
+	type RuntimeHoldReason = RuntimeHoldReason;
 	type Registrar = Registrar;
 	type LeasePeriod = LeasePeriod;
 	type LeaseOffset = LeaseOffset;
diff --git a/polkadot/runtime/common/src/slots/mod.rs b/polkadot/runtime/common/src/slots/mod.rs
index c6276fcfe1b27..09b67c1239ac8 100644
--- a/polkadot/runtime/common/src/slots/mod.rs
+++ b/polkadot/runtime/common/src/slots/mod.rs
@@ -347,14 +347,14 @@ impl<T: Config> Pallet<T> {
 	}
 
 	fn release(leaser: &T::AccountId, amount: BalanceOf<T>) {
-		let amount = T::Currency::release(
+		let released_amount = T::Currency::release(
 			&HoldReason::LeaseDeposit.into(),
 			&leaser,
 			amount,
 			frame_support::traits::tokens::Precision::BestEffort,
 		);
 
-		defensive_assert!(amount.is_ok() && amount.unwrap() == amount);
+		defensive_assert!(released_amount.is_ok() && released_amount.unwrap() == amount);
 	}
 }
 
@@ -548,7 +548,7 @@ mod tests {
 		{
 			System: frame_system::{Pallet, Call, Config<T>, Storage, Event<T>},
 			Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
-			Slots: slots::{Pallet, Call, Storage, Event<T>},
+			Slots: slots::{Pallet, Call, Storage, Event<T>, HoldReason},
 		}
 	);
 

From f812bf272141fad6adcedcf9c49a289bf7601edf Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Wed, 4 Oct 2023 05:27:01 +0200
Subject: [PATCH 03/11] all test pass

---
 .../runtime/common/src/assigned_slots/mod.rs     | 11 ++++++-----
 polkadot/runtime/common/src/auctions.rs          | 16 +++++++++++-----
 polkadot/runtime/common/src/integration_tests.rs |  2 +-
 polkadot/runtime/common/src/slots/mod.rs         |  5 +----
 polkadot/runtime/common/src/traits.rs            |  5 +----
 5 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/polkadot/runtime/common/src/assigned_slots/mod.rs b/polkadot/runtime/common/src/assigned_slots/mod.rs
index bd1bdda1afde6..f7c2889809e24 100644
--- a/polkadot/runtime/common/src/assigned_slots/mod.rs
+++ b/polkadot/runtime/common/src/assigned_slots/mod.rs
@@ -30,7 +30,7 @@ use crate::{
 	slots::{self, Pallet as Slots, WeightInfo as SlotsWeightInfo},
 	traits::{LeaseError, Leaser, Registrar},
 };
-use frame_support::{pallet_prelude::*, traits::{Currency, fungible::Inspect as FunInspect}};
+use frame_support::{pallet_prelude::*, traits::fungible::Inspect as FunInspect};
 use frame_system::pallet_prelude::*;
 pub use pallet::*;
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
@@ -98,9 +98,10 @@ impl WeightInfo for TestWeightInfo {
 	}
 }
 
-type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
-	<T as frame_system::Config>::AccountId,
->>::Balance;
+type BalanceOf<T> =
+	<<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
+		<T as frame_system::Config>::AccountId,
+	>>::Balance;
 
 type LeasePeriodOf<T> = <<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::LeasePeriod;
 
@@ -783,7 +784,7 @@ mod tests {
 	pub fn new_test_ext() -> sp_io::TestExternalities {
 		let mut t = frame_system::GenesisConfig::<Test>::default().build_storage().unwrap();
 		pallet_balances::GenesisConfig::<Test> {
-			balances: vec![(1, 10), (2, 20), (3, 30), (4, 40), (5, 50), (6, 60)],
+			balances: vec![(0, 5), (1, 10), (2, 20), (3, 30), (4, 40), (5, 50), (6, 60)],
 		}
 		.assimilate_storage(&mut t)
 		.unwrap();
diff --git a/polkadot/runtime/common/src/auctions.rs b/polkadot/runtime/common/src/auctions.rs
index 2a937c7322e21..4ec6dcfb854e3 100644
--- a/polkadot/runtime/common/src/auctions.rs
+++ b/polkadot/runtime/common/src/auctions.rs
@@ -25,7 +25,7 @@ use crate::{
 use frame_support::{
 	dispatch::DispatchResult,
 	ensure,
-	traits::{{Currency, Get, Randomness, ReservableCurrency}, fungible::Inspect as FunInspect},
+	traits::{fungible::Inspect as FunInspect, Get, Randomness, ReservableCurrency},
 	weights::Weight,
 };
 use frame_system::pallet_prelude::BlockNumberFor;
@@ -36,9 +36,10 @@ use sp_runtime::traits::{CheckedSub, One, Saturating, Zero};
 use sp_std::{mem::swap, prelude::*};
 
 type CurrencyOf<T> = <T as Config>::Currency;
-type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
-	<T as frame_system::Config>::AccountId,
->>::Balance;
+type BalanceOf<T> =
+	<<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
+		<T as frame_system::Config>::AccountId,
+	>>::Balance;
 
 pub trait WeightInfo {
 	fn new_auction() -> Weight;
@@ -98,7 +99,12 @@ pub mod pallet {
 			LeasePeriod = BlockNumberFor<Self>,
 		>;
 
-		type Currency: ReservableCurrency<Self::AccountId, Balance = <<Self::Leaser as Leaser<BlockNumberFor<Self>>>::Currency as FunInspect<Self::AccountId>>::Balance>;
+		type Currency: ReservableCurrency<
+			Self::AccountId,
+			Balance = <<Self::Leaser as Leaser<BlockNumberFor<Self>>>::Currency as FunInspect<
+				Self::AccountId,
+			>>::Balance,
+		>;
 
 		/// The parachain registrar type.
 		type Registrar: Registrar<AccountId = Self::AccountId>;
diff --git a/polkadot/runtime/common/src/integration_tests.rs b/polkadot/runtime/common/src/integration_tests.rs
index 3560f3481a01d..87d595a386ff4 100644
--- a/polkadot/runtime/common/src/integration_tests.rs
+++ b/polkadot/runtime/common/src/integration_tests.rs
@@ -182,7 +182,7 @@ impl pallet_balances::Config for Test {
 	type ReserveIdentifier = [u8; 8];
 	type RuntimeHoldReason = RuntimeHoldReason;
 	type FreezeIdentifier = ();
-	type MaxHolds = ConstU32<0>;
+	type MaxHolds = ConstU32<1>;
 	type MaxFreezes = ConstU32<0>;
 }
 
diff --git a/polkadot/runtime/common/src/slots/mod.rs b/polkadot/runtime/common/src/slots/mod.rs
index 09b67c1239ac8..0e8f62464d5d5 100644
--- a/polkadot/runtime/common/src/slots/mod.rs
+++ b/polkadot/runtime/common/src/slots/mod.rs
@@ -28,10 +28,7 @@ use crate::traits::{LeaseError, Leaser, Registrar};
 use frame_support::{
 	defensive_assert,
 	pallet_prelude::*,
-	traits::fungible::{
-		hold::{Inspect as FunHoldInspect, Mutate as FunHoldMutate},
-		Inspect as FunInspect, Mutate as FunMutate,
-	},
+	traits::fungible::{hold::Mutate as FunHoldMutate, Inspect as FunInspect},
 	weights::Weight,
 };
 use frame_system::pallet_prelude::*;
diff --git a/polkadot/runtime/common/src/traits.rs b/polkadot/runtime/common/src/traits.rs
index 8fa23fcdf53c1..68256d7234a62 100644
--- a/polkadot/runtime/common/src/traits.rs
+++ b/polkadot/runtime/common/src/traits.rs
@@ -19,10 +19,7 @@
 use frame_support::{
 	dispatch::DispatchResult,
 	traits::{
-		fungible::{
-			hold::{Inspect as FunHoldInspect, Mutate as FunHoldMutate},
-			Inspect as FunInspect, Mutate as FunMutate,
-		},
+		fungible::{hold::Mutate as FunHoldMutate, Inspect as FunInspect},
 		Currency, ReservableCurrency,
 	},
 };

From b5dc2051c96774ef4d5038f47c3646373ebc03e1 Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Wed, 4 Oct 2023 15:33:08 +0200
Subject: [PATCH 04/11] add runtime upgrade

---
 .../runtime/common/src/slots/migration.rs     | 107 ++++++++++++++++++
 1 file changed, 107 insertions(+)

diff --git a/polkadot/runtime/common/src/slots/migration.rs b/polkadot/runtime/common/src/slots/migration.rs
index 4b499ca7c7bd8..5bb876f2c64ba 100644
--- a/polkadot/runtime/common/src/slots/migration.rs
+++ b/polkadot/runtime/common/src/slots/migration.rs
@@ -16,8 +16,115 @@
 
 use super::*;
 use crate::crowdloan;
+use frame_support::traits::OnRuntimeUpgrade;
 use sp_runtime::traits::AccountIdConversion;
 
+#[cfg(feature = "try-runtime")]
+use sp_runtime::TryRuntimeError;
+
+pub mod versioned {
+	use super::*;
+
+	/// Wrapper over `MigrateToV1` with convenience version checks.
+	///
+	/// This migration would move reserves into Named holds.
+	pub type ToV1<T, OldCurrency> = frame_support::migrations::VersionedMigration<
+		0,
+		1,
+		v1::MigrateToV1<T, OldCurrency>,
+		Pallet<T>,
+		<T as frame_system::Config>::DbWeight,
+	>;
+}
+
+mod v1 {
+	use super::*;
+	use frame_support::traits::ReservableCurrency;
+
+	pub type OldBalanceOf<T, OldCurrency> = <OldCurrency as frame_support::traits::Currency<
+		<T as frame_system::Config>::AccountId,
+	>>::Balance;
+
+	#[frame_support::storage_alias]
+	pub type Leases<T: Config, OldCurrency> =
+	StorageMap<Pallet<T>, Twox64Concat, ParaId, Vec<Option<(<T as frame_system::Config>::AccountId, OldBalanceOf<T, OldCurrency>)>>, ValueQuery>;
+
+	/// This migration would move funds for lease from reserved to hold.
+	pub struct MigrateToV1<T, OldCurrency>(
+		sp_std::marker::PhantomData<(T, OldCurrency)>,
+	);
+
+	impl<T, OldCurrency> OnRuntimeUpgrade for MigrateToV1<T, OldCurrency>
+	where
+		T: Config,
+		OldCurrency: ReservableCurrency<<T as frame_system::Config>::AccountId>,
+		BalanceOf<T>: From<OldCurrency::Balance>,
+	{
+		fn on_runtime_upgrade() -> Weight {
+			for (_, lease_periods) in Leases::<T, OldCurrency>::iter() {
+				let mut max_deposits: sp_std::collections::btree_map::BTreeMap<
+					T::AccountId,
+					OldBalanceOf<T, OldCurrency>,
+				> = sp_std::collections::btree_map::BTreeMap::new();
+
+				lease_periods.iter().for_each(|lease| {
+					if let Some((who, amount)) = lease {
+						max_deposits
+							.entry(who.clone())
+							.and_modify(|deposit| *deposit = *amount.max(deposit))
+							.or_insert(*amount);
+					}
+				});
+
+				max_deposits.iter().for_each(|(leaser, deposit)| {
+					OldCurrency::unreserve(leaser, *deposit);
+					let hold_result = Pallet::<T>::hold(leaser, BalanceOf::<T>::from(*deposit));
+					defensive_assert!(
+						hold_result.is_ok(),
+						"hold should not fail, since we just unreserved the same amount; qed"
+					);
+				})
+			}
+
+			// weight: all active lease periods * rw
+			todo!("weights")
+		}
+
+		#[cfg(feature = "try-runtime")]
+		fn post_upgrade(_data: Vec<u8>) -> Result<(), TryRuntimeError> {
+			// let mut para_leasers = sp_std::collections::btree_set::BTreeSet::<(ParaId,
+			// T::AccountId)>::new(); for (para, lease_periods) in Leases::<T>::iter() {
+			// 	lease_periods.into_iter().for_each(|maybe_lease| {
+			// 		if let Some((who, _)) = maybe_lease {
+			// 			para_leasers.insert((para, who));
+			// 		}
+			// 	});
+			// }
+			//
+			// // for each pair assert ReservedAmount is what we expect
+			// para_leasers.iter().try_for_each(|(para, who)| -> Result<(), TryRuntimeError> {
+			// 	let migrated_entry = ReservedAmounts::<T>::get(para, who)
+			// 		.expect("Migration should have inserted this entry");
+			// 	let expected = Pallet::<T>::required_deposit(*para, who);
+			// 	let reserved_balance = T::Currency::reserved_balance(who);
+			//
+			// 	ensure!(
+			// 		migrated_entry == expected,
+			// 		"ReservedAmount value not same as required deposit"
+			// 	);
+			// 	// fixme(ank4n) if there is another reserve on the account, this might be possible.
+			// 	ensure!(
+			// 		migrated_entry == reserved_balance,
+			// 		"ReservedAmount value not same as actual reserved balance"
+			// 	);
+			//
+			// 	Ok(())
+			// })
+			todo!()
+		}
+	}
+}
+
 /// Migrations for using fund index to create fund accounts instead of para ID.
 pub mod slots_crowdloan_index_migration {
 	use super::*;

From 710e5f9bf0acb66c5098f3674ad91b56aaec52d5 Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Wed, 4 Oct 2023 15:33:32 +0200
Subject: [PATCH 05/11] doc comments

---
 polkadot/runtime/common/src/slots/migration.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/polkadot/runtime/common/src/slots/migration.rs b/polkadot/runtime/common/src/slots/migration.rs
index 5bb876f2c64ba..5c1a7327dbcc0 100644
--- a/polkadot/runtime/common/src/slots/migration.rs
+++ b/polkadot/runtime/common/src/slots/migration.rs
@@ -41,10 +41,12 @@ mod v1 {
 	use super::*;
 	use frame_support::traits::ReservableCurrency;
 
+	/// Balance type of OldCurrency.
 	pub type OldBalanceOf<T, OldCurrency> = <OldCurrency as frame_support::traits::Currency<
 		<T as frame_system::Config>::AccountId,
 	>>::Balance;
 
+	/// Alias to leases storage map with old currency.
 	#[frame_support::storage_alias]
 	pub type Leases<T: Config, OldCurrency> =
 	StorageMap<Pallet<T>, Twox64Concat, ParaId, Vec<Option<(<T as frame_system::Config>::AccountId, OldBalanceOf<T, OldCurrency>)>>, ValueQuery>;

From a7eff680b947710a89ad0fc28d324173dd72fb88 Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Wed, 4 Oct 2023 15:51:38 +0200
Subject: [PATCH 06/11] add migration for reserve to fungibles

---
 polkadot/runtime/common/src/auctions.rs       |  2 +-
 .../runtime/common/src/slots/migration.rs     | 88 ++++++++++---------
 2 files changed, 46 insertions(+), 44 deletions(-)

diff --git a/polkadot/runtime/common/src/auctions.rs b/polkadot/runtime/common/src/auctions.rs
index 4ec6dcfb854e3..2e62bb791ac7c 100644
--- a/polkadot/runtime/common/src/auctions.rs
+++ b/polkadot/runtime/common/src/auctions.rs
@@ -686,7 +686,7 @@ mod tests {
 	use ::test_helpers::{dummy_hash, dummy_head_data, dummy_validation_code};
 	use frame_support::{
 		assert_noop, assert_ok, assert_storage_noop, ord_parameter_types, parameter_types,
-		traits::{ConstU32, EitherOfDiverse, OnFinalize, OnInitialize},
+		traits::{ConstU32, EitherOfDiverse, OnFinalize, OnInitialize, Currency},
 	};
 	use frame_system::{EnsureRoot, EnsureSignedBy};
 	use pallet_balances;
diff --git a/polkadot/runtime/common/src/slots/migration.rs b/polkadot/runtime/common/src/slots/migration.rs
index 5c1a7327dbcc0..55f213c7918ff 100644
--- a/polkadot/runtime/common/src/slots/migration.rs
+++ b/polkadot/runtime/common/src/slots/migration.rs
@@ -40,6 +40,7 @@ pub mod versioned {
 mod v1 {
 	use super::*;
 	use frame_support::traits::ReservableCurrency;
+	use sp_std::collections::btree_map::BTreeMap;
 
 	/// Balance type of OldCurrency.
 	pub type OldBalanceOf<T, OldCurrency> = <OldCurrency as frame_support::traits::Currency<
@@ -48,13 +49,16 @@ mod v1 {
 
 	/// Alias to leases storage map with old currency.
 	#[frame_support::storage_alias]
-	pub type Leases<T: Config, OldCurrency> =
-	StorageMap<Pallet<T>, Twox64Concat, ParaId, Vec<Option<(<T as frame_system::Config>::AccountId, OldBalanceOf<T, OldCurrency>)>>, ValueQuery>;
+	pub type OldLeases<T: Config, OldCurrency> = StorageMap<
+		Pallet<T>,
+		Twox64Concat,
+		ParaId,
+		Vec<Option<(<T as frame_system::Config>::AccountId, OldBalanceOf<T, OldCurrency>)>>,
+		ValueQuery,
+	>;
 
 	/// This migration would move funds for lease from reserved to hold.
-	pub struct MigrateToV1<T, OldCurrency>(
-		sp_std::marker::PhantomData<(T, OldCurrency)>,
-	);
+	pub struct MigrateToV1<T, OldCurrency>(sp_std::marker::PhantomData<(T, OldCurrency)>);
 
 	impl<T, OldCurrency> OnRuntimeUpgrade for MigrateToV1<T, OldCurrency>
 	where
@@ -63,66 +67,64 @@ mod v1 {
 		BalanceOf<T>: From<OldCurrency::Balance>,
 	{
 		fn on_runtime_upgrade() -> Weight {
-			for (_, lease_periods) in Leases::<T, OldCurrency>::iter() {
-				let mut max_deposits: sp_std::collections::btree_map::BTreeMap<
-					T::AccountId,
-					OldBalanceOf<T, OldCurrency>,
-				> = sp_std::collections::btree_map::BTreeMap::new();
+			let mut migrated = 0u32;
+			for (_, lease_periods) in OldLeases::<T, OldCurrency>::iter() {
+				let mut deposit_held: BTreeMap<T::AccountId, OldBalanceOf<T, OldCurrency>> =
+					BTreeMap::new();
 
+				// go through each lease and find the max lease deposit required for each leaser.
 				lease_periods.iter().for_each(|lease| {
 					if let Some((who, amount)) = lease {
-						max_deposits
+						deposit_held
 							.entry(who.clone())
 							.and_modify(|deposit| *deposit = *amount.max(deposit))
 							.or_insert(*amount);
 					}
 				});
 
-				max_deposits.iter().for_each(|(leaser, deposit)| {
+				deposit_held.iter().for_each(|(leaser, deposit)| {
 					OldCurrency::unreserve(leaser, *deposit);
 					let hold_result = Pallet::<T>::hold(leaser, BalanceOf::<T>::from(*deposit));
 					defensive_assert!(
 						hold_result.is_ok(),
-						"hold should not fail, since we just unreserved the same amount; qed"
+						"hold should not fail, since we just unreserved the same amount"
 					);
+					migrated += 1;
 				})
 			}
 
 			// weight: all active lease periods * rw
-			todo!("weights")
+			T::DbWeight::get().reads_writes(migrated.saturating_mul(2).saturating_add(2).into(), 2)
 		}
 
 		#[cfg(feature = "try-runtime")]
 		fn post_upgrade(_data: Vec<u8>) -> Result<(), TryRuntimeError> {
-			// let mut para_leasers = sp_std::collections::btree_set::BTreeSet::<(ParaId,
-			// T::AccountId)>::new(); for (para, lease_periods) in Leases::<T>::iter() {
-			// 	lease_periods.into_iter().for_each(|maybe_lease| {
-			// 		if let Some((who, _)) = maybe_lease {
-			// 			para_leasers.insert((para, who));
-			// 		}
-			// 	});
-			// }
-			//
-			// // for each pair assert ReservedAmount is what we expect
-			// para_leasers.iter().try_for_each(|(para, who)| -> Result<(), TryRuntimeError> {
-			// 	let migrated_entry = ReservedAmounts::<T>::get(para, who)
-			// 		.expect("Migration should have inserted this entry");
-			// 	let expected = Pallet::<T>::required_deposit(*para, who);
-			// 	let reserved_balance = T::Currency::reserved_balance(who);
-			//
-			// 	ensure!(
-			// 		migrated_entry == expected,
-			// 		"ReservedAmount value not same as required deposit"
-			// 	);
-			// 	// fixme(ank4n) if there is another reserve on the account, this might be possible.
-			// 	ensure!(
-			// 		migrated_entry == reserved_balance,
-			// 		"ReservedAmount value not same as actual reserved balance"
-			// 	);
-			//
-			// 	Ok(())
-			// })
-			todo!()
+			// Build a set of pairs of (para, who) that have a lease.
+			let mut para_leasers = sp_std::collections::btree_set::BTreeSet::<(ParaId,
+			T::AccountId)>::new();
+			for (para, lease_periods) in Leases::<T>::iter() {
+				lease_periods.into_iter().for_each(|maybe_lease| {
+					if let Some((who, _)) = maybe_lease {
+						para_leasers.insert((para, who));
+					}
+				});
+			}
+
+			// for each pair assert hold amount is what we expect
+			para_leasers.iter().try_for_each(|(para, who)| -> Result<(), TryRuntimeError> {
+				// fixme(ank4n) there is a case where an account has a hold for multiple para-ids..
+				// TODO(ank4n) Add integrity check..
+				let actual_hold = T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), who)
+					.expect("Migration should have inserted this entry");
+				let expected_hold = Pallet::<T>::deposit_held(*para, who);
+
+				ensure!(
+					actual_hold == expected_hold,
+					"ReservedAmount value not same as actual reserved balance"
+				);
+
+				Ok(())
+			})
 		}
 	}
 }

From 52a12bdcc7e706812ae025a4aee31722c0372442 Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Thu, 5 Oct 2023 09:47:04 +0200
Subject: [PATCH 07/11] add migration to westend runtime

---
 .../runtime/common/src/slots/migration.rs     | 21 +++++++++++++------
 polkadot/runtime/common/src/slots/mod.rs      |  1 +
 polkadot/runtime/westend/src/lib.rs           |  5 ++++-
 3 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/polkadot/runtime/common/src/slots/migration.rs b/polkadot/runtime/common/src/slots/migration.rs
index 55f213c7918ff..092eb05ae4ce3 100644
--- a/polkadot/runtime/common/src/slots/migration.rs
+++ b/polkadot/runtime/common/src/slots/migration.rs
@@ -22,12 +22,15 @@ use sp_runtime::traits::AccountIdConversion;
 #[cfg(feature = "try-runtime")]
 use sp_runtime::TryRuntimeError;
 
+/// The current storage version.
+pub const STORAGE_VERSION: StorageVersion = StorageVersion::new(2);
+
 pub mod versioned {
 	use super::*;
 
 	/// Wrapper over `MigrateToV1` with convenience version checks.
 	///
-	/// This migration would move reserves into Named holds.
+	/// This migration would move lease reserves into named holds.
 	pub type ToV1<T, OldCurrency> = frame_support::migrations::VersionedMigration<
 		0,
 		1,
@@ -67,12 +70,16 @@ mod v1 {
 		BalanceOf<T>: From<OldCurrency::Balance>,
 	{
 		fn on_runtime_upgrade() -> Weight {
-			let mut migrated = 0u32;
+			// useful for calculating weights later
+			let mut migrated = 0u64;
+			let mut leases_count = 0u64;
+
 			for (_, lease_periods) in OldLeases::<T, OldCurrency>::iter() {
+				leases_count += 1;
 				let mut deposit_held: BTreeMap<T::AccountId, OldBalanceOf<T, OldCurrency>> =
 					BTreeMap::new();
 
-				// go through each lease and find the max lease deposit required for each leaser.
+				// go through each lease and find the lease deposit required for each leaser.
 				lease_periods.iter().for_each(|lease| {
 					if let Some((who, amount)) = lease {
 						deposit_held
@@ -93,8 +100,11 @@ mod v1 {
 				})
 			}
 
-			// weight: all active lease periods * rw
-			T::DbWeight::get().reads_writes(migrated.saturating_mul(2).saturating_add(2).into(), 2)
+			T::DbWeight::get().reads_writes(
+				// reads: leases_count
+				leases_count,
+				// writes = migrated * (unreserve + hold)
+				migrated.saturating_mul(2))
 		}
 
 		#[cfg(feature = "try-runtime")]
@@ -113,7 +123,6 @@ mod v1 {
 			// for each pair assert hold amount is what we expect
 			para_leasers.iter().try_for_each(|(para, who)| -> Result<(), TryRuntimeError> {
 				// fixme(ank4n) there is a case where an account has a hold for multiple para-ids..
-				// TODO(ank4n) Add integrity check..
 				let actual_hold = T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), who)
 					.expect("Migration should have inserted this entry");
 				let expected_hold = Pallet::<T>::deposit_held(*para, who);
diff --git a/polkadot/runtime/common/src/slots/mod.rs b/polkadot/runtime/common/src/slots/mod.rs
index 0e8f62464d5d5..0f1a2fe37d2d2 100644
--- a/polkadot/runtime/common/src/slots/mod.rs
+++ b/polkadot/runtime/common/src/slots/mod.rs
@@ -70,6 +70,7 @@ pub mod pallet {
 	use super::*;
 
 	#[pallet::pallet]
+	#[pallet::storage_version(migration::STORAGE_VERSION)]
 	#[pallet::without_storage_info]
 	pub struct Pallet<T>(_);
 
diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index 6085b6e37455b..e11e796ec7a62 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -1255,6 +1255,7 @@ parameter_types! {
 impl slots::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Currency = Balances;
+	type RuntimeHoldReason = RuntimeHoldReason;
 	type Registrar = Registrar;
 	type LeasePeriod = LeasePeriod;
 	type LeaseOffset = ();
@@ -1294,6 +1295,7 @@ parameter_types! {
 impl auctions::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Leaser = Slots;
+	type Currency = Balances;
 	type Registrar = Registrar;
 	type EndingPeriod = EndingPeriod;
 	type SampleLength = SampleLength;
@@ -1432,7 +1434,7 @@ construct_runtime! {
 
 		// Parachain Onboarding Pallets. Start indices at 60 to leave room.
 		Registrar: paras_registrar::{Pallet, Call, Storage, Event<T>, Config<T>} = 60,
-		Slots: slots::{Pallet, Call, Storage, Event<T>} = 61,
+		Slots: slots::{Pallet, Call, Storage, Event<T>, HoldReason} = 61,
 		ParasSudoWrapper: paras_sudo_wrapper::{Pallet, Call} = 62,
 		Auctions: auctions::{Pallet, Call, Storage, Event<T>} = 63,
 		Crowdloan: crowdloan::{Pallet, Call, Storage, Event<T>} = 64,
@@ -1509,6 +1511,7 @@ pub mod migrations {
 		pallet_nomination_pools::migration::versioned_migrations::V5toV6<Runtime>,
 		pallet_referenda::migration::v1::MigrateV0ToV1<Runtime, ()>,
 		pallet_nomination_pools::migration::versioned_migrations::V6ToV7<Runtime>,
+		slots::migration::versioned::ToV1<Runtime, Balances>,
 	);
 }
 

From c01e72bda301aa8f026c0c653faf5dea82a7636b Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Sun, 8 Oct 2023 22:40:10 +0200
Subject: [PATCH 08/11] compile things

---
 polkadot/runtime/rococo/src/lib.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/polkadot/runtime/rococo/src/lib.rs b/polkadot/runtime/rococo/src/lib.rs
index 4bdcc1237394e..cf615082429aa 100644
--- a/polkadot/runtime/rococo/src/lib.rs
+++ b/polkadot/runtime/rococo/src/lib.rs
@@ -997,6 +997,7 @@ parameter_types! {
 impl slots::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Currency = Balances;
+	type RuntimeHoldReason = RuntimeHoldReason;
 	type Registrar = Registrar;
 	type LeasePeriod = LeasePeriod;
 	type LeaseOffset = ();
@@ -1036,6 +1037,7 @@ parameter_types! {
 impl auctions::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type Leaser = Slots;
+	type Currency = Balances;
 	type Registrar = Registrar;
 	type EndingPeriod = EndingPeriod;
 	type SampleLength = SampleLength;
@@ -1061,7 +1063,7 @@ impl pallet_balances::Config<NisCounterpartInstance> for Runtime {
 	type WeightInfo = weights::pallet_balances_nis_counterpart_balances::WeightInfo<Runtime>;
 	type RuntimeHoldReason = RuntimeHoldReason;
 	type FreezeIdentifier = ();
-	type MaxHolds = ConstU32<0>;
+	type MaxHolds = ConstU32<1>;
 	type MaxFreezes = ConstU32<0>;
 }
 
@@ -1309,7 +1311,7 @@ construct_runtime! {
 
 		// Parachain Onboarding Pallets. Start indices at 70 to leave room.
 		Registrar: paras_registrar::{Pallet, Call, Storage, Event<T>, Config<T>} = 70,
-		Slots: slots::{Pallet, Call, Storage, Event<T>} = 71,
+		Slots: slots::{Pallet, Call, Storage, Event<T>, HoldReason} = 71,
 		Auctions: auctions::{Pallet, Call, Storage, Event<T>} = 72,
 		Crowdloan: crowdloan::{Pallet, Call, Storage, Event<T>} = 73,
 

From e0fa97a1c8ec7dd98da9fb645328778940c6fe39 Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Mon, 9 Oct 2023 00:35:11 +0200
Subject: [PATCH 09/11] fix benchmark compile

---
 .../common/src/assigned_slots/benchmarking.rs       |  7 +++----
 polkadot/runtime/common/src/auctions.rs             |  8 +++-----
 polkadot/runtime/common/src/slots/migration.rs      |  6 ++++--
 polkadot/runtime/common/src/slots/mod.rs            | 13 ++++++++-----
 polkadot/runtime/common/src/traits.rs               |  4 ++--
 5 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/polkadot/runtime/common/src/assigned_slots/benchmarking.rs b/polkadot/runtime/common/src/assigned_slots/benchmarking.rs
index 61638fe6cabfc..16df7f947bace 100644
--- a/polkadot/runtime/common/src/assigned_slots/benchmarking.rs
+++ b/polkadot/runtime/common/src/assigned_slots/benchmarking.rs
@@ -20,19 +20,18 @@
 use super::*;
 
 use frame_benchmarking::v2::*;
-use frame_support::assert_ok;
 use frame_system::{pallet_prelude::BlockNumberFor, RawOrigin};
 use primitives::Id as ParaId;
 use sp_runtime::traits::Bounded;
 
 type CurrencyOf<T> = <<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency;
-type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as Currency<
+type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
 	<T as frame_system::Config>::AccountId,
 >>::Balance;
 #[benchmarks(where T: Config)]
 mod benchmarks {
 	use super::*;
-
+	use frame_support::{assert_ok, traits::fungible::Mutate};
 	use crate::assigned_slots::Pallet as AssignedSlots;
 
 	fn register_parachain<T: Config>(para_id: ParaId) {
@@ -40,7 +39,7 @@ mod benchmarks {
 		let worst_validation_code = T::Registrar::worst_validation_code();
 		let worst_head_data = T::Registrar::worst_head_data();
 
-		CurrencyOf::<T>::make_free_balance_be(&who, BalanceOf::<T>::max_value());
+		CurrencyOf::<T>::set_balance(&who, BalanceOf::<T>::max_value());
 
 		assert_ok!(T::Registrar::register(
 			who,
diff --git a/polkadot/runtime/common/src/auctions.rs b/polkadot/runtime/common/src/auctions.rs
index 2e62bb791ac7c..49c499b74fac6 100644
--- a/polkadot/runtime/common/src/auctions.rs
+++ b/polkadot/runtime/common/src/auctions.rs
@@ -25,7 +25,7 @@ use crate::{
 use frame_support::{
 	dispatch::DispatchResult,
 	ensure,
-	traits::{fungible::Inspect as FunInspect, Get, Randomness, ReservableCurrency},
+	traits::{fungible::Inspect as FunInspect, Currency, Get, Randomness, ReservableCurrency},
 	weights::Weight,
 };
 use frame_system::pallet_prelude::BlockNumberFor;
@@ -37,9 +37,7 @@ use sp_std::{mem::swap, prelude::*};
 
 type CurrencyOf<T> = <T as Config>::Currency;
 type BalanceOf<T> =
-	<<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
-		<T as frame_system::Config>::AccountId,
-	>>::Balance;
+	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
 
 pub trait WeightInfo {
 	fn new_auction() -> Weight;
@@ -686,7 +684,7 @@ mod tests {
 	use ::test_helpers::{dummy_hash, dummy_head_data, dummy_validation_code};
 	use frame_support::{
 		assert_noop, assert_ok, assert_storage_noop, ord_parameter_types, parameter_types,
-		traits::{ConstU32, EitherOfDiverse, OnFinalize, OnInitialize, Currency},
+		traits::{ConstU32, Currency, EitherOfDiverse, OnFinalize, OnInitialize},
 	};
 	use frame_system::{EnsureRoot, EnsureSignedBy};
 	use pallet_balances;
diff --git a/polkadot/runtime/common/src/slots/migration.rs b/polkadot/runtime/common/src/slots/migration.rs
index 092eb05ae4ce3..49b49ffda64e7 100644
--- a/polkadot/runtime/common/src/slots/migration.rs
+++ b/polkadot/runtime/common/src/slots/migration.rs
@@ -45,6 +45,9 @@ mod v1 {
 	use frame_support::traits::ReservableCurrency;
 	use sp_std::collections::btree_map::BTreeMap;
 
+	#[cfg(feature = "try-runtime")]
+	use frame_support::traits::fungible::InspectHold;
+
 	/// Balance type of OldCurrency.
 	pub type OldBalanceOf<T, OldCurrency> = <OldCurrency as frame_support::traits::Currency<
 		<T as frame_system::Config>::AccountId,
@@ -123,8 +126,7 @@ mod v1 {
 			// for each pair assert hold amount is what we expect
 			para_leasers.iter().try_for_each(|(para, who)| -> Result<(), TryRuntimeError> {
 				// fixme(ank4n) there is a case where an account has a hold for multiple para-ids..
-				let actual_hold = T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), who)
-					.expect("Migration should have inserted this entry");
+				let actual_hold = T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), who);
 				let expected_hold = Pallet::<T>::deposit_held(*para, who);
 
 				ensure!(
diff --git a/polkadot/runtime/common/src/slots/mod.rs b/polkadot/runtime/common/src/slots/mod.rs
index 0f1a2fe37d2d2..f3a619ec28a41 100644
--- a/polkadot/runtime/common/src/slots/mod.rs
+++ b/polkadot/runtime/common/src/slots/mod.rs
@@ -28,7 +28,10 @@ use crate::traits::{LeaseError, Leaser, Registrar};
 use frame_support::{
 	defensive_assert,
 	pallet_prelude::*,
-	traits::fungible::{hold::Mutate as FunHoldMutate, Inspect as FunInspect},
+	traits::fungible::{
+		hold::{Inspect as FunHoldInspect, Mutate as FunHoldMutate},
+		Inspect as FunInspect, Mutate as FunMutate,
+	},
 	weights::Weight,
 };
 use frame_system::pallet_prelude::*;
@@ -80,7 +83,8 @@ pub mod pallet {
 		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;
 
 		/// The currency type used for bidding.
-		type Currency: FunHoldMutate<Self::AccountId, Reason = Self::RuntimeHoldReason>;
+		type Currency: FunHoldMutate<Self::AccountId, Reason = Self::RuntimeHoldReason>
+			+ FunMutate<Self::AccountId>;
 
 		/// The hold reason when reserving funds for the lease.
 		type RuntimeHoldReason: From<HoldReason>;
@@ -1159,7 +1163,7 @@ mod benchmarking {
 
 			for i in 0 .. max_people {
 				let leaser = account("lease_deposit", i, 0);
-				assert_eq!(T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into, &leaser), T::Currency::minimum_balance());
+				assert_eq!(T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), &leaser), T::Currency::minimum_balance());
 			}
 
 			let origin =
@@ -1168,8 +1172,7 @@ mod benchmarking {
 		verify {
 			for i in 0 .. max_people {
 				let leaser = account("lease_deposit", i, 0);
-				assert_eq!(T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into, &leaser), 0u32.into());
-				assert_eq!(T::Currency::reserved_balance(&leaser), 0u32.into());
+				assert_eq!(T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), &leaser), 0u32.into());
 			}
 		}
 
diff --git a/polkadot/runtime/common/src/traits.rs b/polkadot/runtime/common/src/traits.rs
index 68256d7234a62..759b8c027c6e8 100644
--- a/polkadot/runtime/common/src/traits.rs
+++ b/polkadot/runtime/common/src/traits.rs
@@ -19,7 +19,7 @@
 use frame_support::{
 	dispatch::DispatchResult,
 	traits::{
-		fungible::{hold::Mutate as FunHoldMutate, Inspect as FunInspect},
+		fungible::{hold::Mutate as FunHoldMutate, Inspect as FunInspect, Mutate as FunMutate},
 		Currency, ReservableCurrency,
 	},
 };
@@ -112,7 +112,7 @@ pub trait Leaser<BlockNumber> {
 	type LeasePeriod;
 
 	/// The currency type in which the lease is taken.
-	type Currency: FunHoldMutate<Self::AccountId>;
+	type Currency: FunHoldMutate<Self::AccountId> + FunMutate<Self::AccountId>;
 
 	/// Lease a new parachain slot for `para`.
 	///

From 716ab455cbbd5c1c60378e9d173e48f89e9a4abd Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Mon, 9 Oct 2023 02:58:46 +0200
Subject: [PATCH 10/11] fmt

---
 .../runtime/common/src/assigned_slots/benchmarking.rs  |  9 +++++----
 polkadot/runtime/common/src/slots/migration.rs         | 10 ++++++----
 polkadot/runtime/common/src/slots/mod.rs               |  7 ++-----
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/polkadot/runtime/common/src/assigned_slots/benchmarking.rs b/polkadot/runtime/common/src/assigned_slots/benchmarking.rs
index 16df7f947bace..affe8ef417887 100644
--- a/polkadot/runtime/common/src/assigned_slots/benchmarking.rs
+++ b/polkadot/runtime/common/src/assigned_slots/benchmarking.rs
@@ -25,14 +25,15 @@ use primitives::Id as ParaId;
 use sp_runtime::traits::Bounded;
 
 type CurrencyOf<T> = <<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency;
-type BalanceOf<T> = <<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
-	<T as frame_system::Config>::AccountId,
->>::Balance;
+type BalanceOf<T> =
+	<<<T as Config>::Leaser as Leaser<BlockNumberFor<T>>>::Currency as FunInspect<
+		<T as frame_system::Config>::AccountId,
+	>>::Balance;
 #[benchmarks(where T: Config)]
 mod benchmarks {
 	use super::*;
-	use frame_support::{assert_ok, traits::fungible::Mutate};
 	use crate::assigned_slots::Pallet as AssignedSlots;
+	use frame_support::{assert_ok, traits::fungible::Mutate};
 
 	fn register_parachain<T: Config>(para_id: ParaId) {
 		let who: T::AccountId = whitelisted_caller();
diff --git a/polkadot/runtime/common/src/slots/migration.rs b/polkadot/runtime/common/src/slots/migration.rs
index 49b49ffda64e7..6fc928ad5038e 100644
--- a/polkadot/runtime/common/src/slots/migration.rs
+++ b/polkadot/runtime/common/src/slots/migration.rs
@@ -107,14 +107,15 @@ mod v1 {
 				// reads: leases_count
 				leases_count,
 				// writes = migrated * (unreserve + hold)
-				migrated.saturating_mul(2))
+				migrated.saturating_mul(2),
+			)
 		}
 
 		#[cfg(feature = "try-runtime")]
 		fn post_upgrade(_data: Vec<u8>) -> Result<(), TryRuntimeError> {
 			// Build a set of pairs of (para, who) that have a lease.
-			let mut para_leasers = sp_std::collections::btree_set::BTreeSet::<(ParaId,
-			T::AccountId)>::new();
+			let mut para_leasers =
+				sp_std::collections::btree_set::BTreeSet::<(ParaId, T::AccountId)>::new();
 			for (para, lease_periods) in Leases::<T>::iter() {
 				lease_periods.into_iter().for_each(|maybe_lease| {
 					if let Some((who, _)) = maybe_lease {
@@ -126,7 +127,8 @@ mod v1 {
 			// for each pair assert hold amount is what we expect
 			para_leasers.iter().try_for_each(|(para, who)| -> Result<(), TryRuntimeError> {
 				// fixme(ank4n) there is a case where an account has a hold for multiple para-ids..
-				let actual_hold = T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), who);
+				let actual_hold =
+					T::Currency::balance_on_hold(&HoldReason::LeaseDeposit.into(), who);
 				let expected_hold = Pallet::<T>::deposit_held(*para, who);
 
 				ensure!(
diff --git a/polkadot/runtime/common/src/slots/mod.rs b/polkadot/runtime/common/src/slots/mod.rs
index f3a619ec28a41..3641cd5edfde2 100644
--- a/polkadot/runtime/common/src/slots/mod.rs
+++ b/polkadot/runtime/common/src/slots/mod.rs
@@ -28,10 +28,7 @@ use crate::traits::{LeaseError, Leaser, Registrar};
 use frame_support::{
 	defensive_assert,
 	pallet_prelude::*,
-	traits::fungible::{
-		hold::{Inspect as FunHoldInspect, Mutate as FunHoldMutate},
-		Inspect as FunInspect, Mutate as FunMutate,
-	},
+	traits::fungible::{hold::Mutate as FunHoldMutate, Inspect as FunInspect, Mutate as FunMutate},
 	weights::Weight,
 };
 use frame_system::pallet_prelude::*;
@@ -1016,7 +1013,7 @@ mod tests {
 #[cfg(feature = "runtime-benchmarks")]
 mod benchmarking {
 	use super::*;
-	use frame_support::assert_ok;
+	use frame_support::{assert_ok, traits::fungible::hold::Inspect};
 	use frame_system::RawOrigin;
 	use runtime_parachains::paras;
 	use sp_runtime::traits::{Bounded, One};

From 1f7c6ab80a827eb4e05bba19969b78101ad099af Mon Sep 17 00:00:00 2001
From: Ankan <ankan.anurag@gmail.com>
Date: Mon, 9 Oct 2023 03:14:04 +0200
Subject: [PATCH 11/11] fix storage version

---
 polkadot/runtime/common/src/slots/migration.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/polkadot/runtime/common/src/slots/migration.rs b/polkadot/runtime/common/src/slots/migration.rs
index 6fc928ad5038e..8d586df07a59f 100644
--- a/polkadot/runtime/common/src/slots/migration.rs
+++ b/polkadot/runtime/common/src/slots/migration.rs
@@ -23,7 +23,7 @@ use sp_runtime::traits::AccountIdConversion;
 use sp_runtime::TryRuntimeError;
 
 /// The current storage version.
-pub const STORAGE_VERSION: StorageVersion = StorageVersion::new(2);
+pub const STORAGE_VERSION: StorageVersion = StorageVersion::new(1);
 
 pub mod versioned {
 	use super::*;