Migrate fee payment from Currency to fungible (#2292)

Part of https://github.com/paritytech/polkadot-sdk/issues/226 
Related https://github.com/paritytech/polkadot-sdk/issues/1833

- Deprecate `CurrencyAdapter` and introduce `FungibleAdapter`
- Deprecate `ToStakingPot` and replace usage with `ResolveTo`
- Required creating a new `StakingPotAccountId` struct that implements
`TypedGet` for the staking pot account ID
- Update parachain common utils `DealWithFees`, `ToAuthor` and
`AssetsToBlockAuthor` implementations to use `fungible`
- Update runtime XCM Weight Traders to use `ResolveTo` instead of
`ToStakingPot`
- Update runtime Transaction Payment pallets to use `FungibleAdapter`
instead of `CurrencyAdapter`
- [x] Blocked by https://github.com/paritytech/polkadot-sdk/pull/1296,
needs the `Unbalanced::decrease_balance` fix

bridges/bin/runtime-common/src/mock.rs

@@ -166,7 +166,7 @@ impl pallet_balances::Config for TestRuntime {
 
 #[derive_impl(pallet_transaction_payment::config_preludes::TestDefaultConfig)]
 impl pallet_transaction_payment::Config for TestRuntime {
-	type OnChargeTransaction = pallet_transaction_payment::CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = pallet_transaction_payment::FungibleAdapter<Balances, ()>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = IdentityFee<ThisChainBalance>;
 	type LengthToFee = ConstantMultiplier<ThisChainBalance, TransactionByteFee>;

cumulus/pallets/collator-selection/src/lib.rs

@@ -81,6 +81,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+use core::marker::PhantomData;
+use frame_support::traits::TypedGet;
 pub use pallet::*;
 
 #[cfg(test)]
@@ -981,3 +983,15 @@ pub mod pallet {
 		}
 	}
 }
+
+/// [`TypedGet`] implementaion to get the AccountId of the StakingPot.
+pub struct StakingPotAccountId<R>(PhantomData<R>);
+impl<R> TypedGet for StakingPotAccountId<R>
+where
+	R: crate::Config,
+{
+	type Type = <R as frame_system::Config>::AccountId;
+	fn get() -> Self::Type {
+		<crate::Pallet<R>>::account_id()
+	}
+}

cumulus/parachains/common/src/impls.rs

@@ -17,10 +17,11 @@
 //! Taken from polkadot/runtime/common (at a21cd64) and adapted for parachains.
 
 use frame_support::traits::{
-	fungibles::{self, Balanced, Credit},
-	Contains, ContainsPair, Currency, Get, Imbalance, OnUnbalanced, OriginTrait,
+	fungible, fungibles, tokens::imbalance::ResolveTo, Contains, ContainsPair, Currency, Defensive,
+	Get, Imbalance, OnUnbalanced, OriginTrait,
 };
 use pallet_asset_tx_payment::HandleCredit;
+use pallet_collator_selection::StakingPotAccountId;
 use sp_runtime::traits::Zero;
 use sp_std::{marker::PhantomData, prelude::*};
 use xcm::latest::{
@@ -29,16 +30,20 @@ use xcm::latest::{
 };
 use xcm_executor::traits::ConvertLocation;
 
+/// Type alias to conveniently refer to `frame_system`'s `Config::AccountId`.
+pub type AccountIdOf<T> = <T as frame_system::Config>::AccountId;
+
 /// Type alias to conveniently refer to the `Currency::NegativeImbalance` associated type.
 pub type NegativeImbalance<T> = <pallet_balances::Pallet<T> as Currency<
 	<T as frame_system::Config>::AccountId,
 >>::NegativeImbalance;
 
-/// Type alias to conveniently refer to `frame_system`'s `Config::AccountId`.
-pub type AccountIdOf<R> = <R as frame_system::Config>::AccountId;
-
 /// Implementation of `OnUnbalanced` that deposits the fees into a staking pot for later payout.
+#[deprecated(
+	note = "ToStakingPot is deprecated and will be removed after March 2024. Please use frame_support::traits::tokens::imbalance::ResolveTo instead."
+)]
 pub struct ToStakingPot<R>(PhantomData<R>);
+#[allow(deprecated)]
 impl<R> OnUnbalanced<NegativeImbalance<R>> for ToStakingPot<R>
 where
 	R: pallet_balances::Config + pallet_collator_selection::Config,
@@ -47,25 +52,30 @@ where
 {
 	fn on_nonzero_unbalanced(amount: NegativeImbalance<R>) {
 		let staking_pot = <pallet_collator_selection::Pallet<R>>::account_id();
+		// In case of error: Will drop the result triggering the `OnDrop` of the imbalance.
 		<pallet_balances::Pallet<R>>::resolve_creating(&staking_pot, amount);
 	}
 }
 
-/// Implementation of `OnUnbalanced` that deals with the fees by combining tip and fee and passing
-/// the result on to `ToStakingPot`.
+/// Fungible implementation of `OnUnbalanced` that deals with the fees by combining tip and fee and
+/// passing the result on to `ToStakingPot`.
 pub struct DealWithFees<R>(PhantomData<R>);
-impl<R> OnUnbalanced<NegativeImbalance<R>> for DealWithFees<R>
+impl<R> OnUnbalanced<fungible::Credit<R::AccountId, pallet_balances::Pallet<R>>> for DealWithFees<R>
 where
 	R: pallet_balances::Config + pallet_collator_selection::Config,
 	AccountIdOf<R>: From<polkadot_primitives::AccountId> + Into<polkadot_primitives::AccountId>,
 	<R as frame_system::Config>::RuntimeEvent: From<pallet_balances::Event<R>>,
 {
-	fn on_unbalanceds<B>(mut fees_then_tips: impl Iterator<Item = NegativeImbalance<R>>) {
+	fn on_unbalanceds<B>(
+		mut fees_then_tips: impl Iterator<
+			Item = fungible::Credit<R::AccountId, pallet_balances::Pallet<R>>,
+		>,
+	) {
 		if let Some(mut fees) = fees_then_tips.next() {
 			if let Some(tips) = fees_then_tips.next() {
 				tips.merge_into(&mut fees);
 			}
-			<ToStakingPot<R> as OnUnbalanced<_>>::on_unbalanced(fees);
+			ResolveTo::<StakingPotAccountId<R>, pallet_balances::Pallet<R>>::on_unbalanced(fees)
 		}
 	}
 }
@@ -79,10 +89,11 @@ where
 	R: pallet_authorship::Config + pallet_assets::Config<I>,
 	AccountIdOf<R>: From<polkadot_primitives::AccountId> + Into<polkadot_primitives::AccountId>,
 {
-	fn handle_credit(credit: Credit<AccountIdOf<R>, pallet_assets::Pallet<R, I>>) {
+	fn handle_credit(credit: fungibles::Credit<AccountIdOf<R>, pallet_assets::Pallet<R, I>>) {
+		use frame_support::traits::fungibles::Balanced;
 		if let Some(author) = pallet_authorship::Pallet::<R>::author() {
 			// In case of error: Will drop the result triggering the `OnDrop` of the imbalance.
-			let _ = pallet_assets::Pallet::<R, I>::resolve(&author, credit);
+			let _ = pallet_assets::Pallet::<R, I>::resolve(&author, credit).defensive();
 		}
 	}
 }
@@ -313,8 +324,14 @@ mod tests {
 	#[test]
 	fn test_fees_and_tip_split() {
 		new_test_ext().execute_with(|| {
-			let fee = Balances::issue(10);
-			let tip = Balances::issue(20);
+			let fee =
+				<pallet_balances::Pallet<Test> as frame_support::traits::fungible::Balanced<
+					AccountId,
+				>>::issue(10);
+			let tip =
+				<pallet_balances::Pallet<Test> as frame_support::traits::fungible::Balanced<
+					AccountId,
+				>>::issue(20);
 
 			assert_eq!(Balances::free_balance(TEST_ACCOUNT), 0);
 

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/lib.rs

@@ -226,7 +226,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
 	type FeeMultiplierUpdate = SlowAdjustingFeeUpdate<Self>;

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/xcm_config.rs

@@ -27,14 +27,13 @@ use assets_common::{
 use frame_support::{
 	parameter_types,
 	traits::{
-		tokens::imbalance::ResolveAssetTo, ConstU32, Contains, Equals, Everything, Nothing,
-		PalletInfoAccess,
+		tokens::imbalance::{ResolveAssetTo, ResolveTo},
+		ConstU32, Contains, Equals, Everything, Nothing, PalletInfoAccess,
 	},
 };
 use frame_system::EnsureRoot;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, AssetFeeAsExistentialDepositMultiplier,
 		ConcreteAssetFromSystem, ParentRelayOrSiblingParachains, RelayOrOtherSystemParachains,
@@ -569,7 +568,13 @@ impl xcm_executor::Config for XcmConfig {
 		MaxInstructions,
 	>;
 	type Trader = (
-		UsingComponents<WeightToFee, TokenLocation, AccountId, Balances, ToStakingPot<Runtime>>,
+		UsingComponents<
+			WeightToFee,
+			TokenLocation,
+			AccountId,
+			Balances,
+			ResolveTo<StakingPot, Balances>,
+		>,
 		cumulus_primitives_utility::SwapFirstAssetTrader<
 			TokenLocationV3,
 			crate::AssetConversion,

cumulus/parachains/runtimes/assets/asset-hub-westend/src/lib.rs

@@ -210,7 +210,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
 	type FeeMultiplierUpdate = SlowAdjustingFeeUpdate<Self>;

cumulus/parachains/runtimes/assets/asset-hub-westend/src/xcm_config.rs

@@ -27,14 +27,13 @@ use assets_common::{
 use frame_support::{
 	parameter_types,
 	traits::{
-		tokens::imbalance::ResolveAssetTo, ConstU32, Contains, Equals, Everything, Nothing,
-		PalletInfoAccess,
+		tokens::imbalance::{ResolveAssetTo, ResolveTo},
+		ConstU32, Contains, Equals, Everything, Nothing, PalletInfoAccess,
 	},
 };
 use frame_system::EnsureRoot;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, AssetFeeAsExistentialDepositMultiplier,
 		ConcreteAssetFromSystem, RelayOrOtherSystemParachains,
@@ -591,7 +590,13 @@ impl xcm_executor::Config for XcmConfig {
 		MaxInstructions,
 	>;
 	type Trader = (
-		UsingComponents<WeightToFee, WestendLocation, AccountId, Balances, ToStakingPot<Runtime>>,
+		UsingComponents<
+			WeightToFee,
+			WestendLocation,
+			AccountId,
+			Balances,
+			ResolveTo<StakingPot, Balances>,
+		>,
 		cumulus_primitives_utility::SwapFirstAssetTrader<
 			WestendLocationV3,
 			crate::AssetConversion,

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-rococo/src/lib.rs

@@ -317,7 +317,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-rococo/src/xcm_config.rs

@@ -33,13 +33,13 @@ use bp_relayers::{PayRewardFromAccount, RewardsAccountOwner, RewardsAccountParam
 use bp_runtime::ChainId;
 use frame_support::{
 	parameter_types,
-	traits::{ConstU32, Contains, Equals, Everything, Nothing},
+	traits::{tokens::imbalance::ResolveTo, ConstU32, Contains, Equals, Everything, Nothing},
 	StoragePrefixedMap,
 };
 use frame_system::EnsureRoot;
+use pallet_collator_selection::StakingPotAccountId;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
 		RelayOrOtherSystemParachains,
@@ -295,8 +295,13 @@ impl xcm_executor::Config for XcmConfig {
 		RuntimeCall,
 		MaxInstructions,
 	>;
-	type Trader =
-		UsingComponents<WeightToFee, TokenLocation, AccountId, Balances, ToStakingPot<Runtime>>;
+	type Trader = UsingComponents<
+		WeightToFee,
+		TokenLocation,
+		AccountId,
+		Balances,
+		ResolveTo<StakingPotAccountId<Runtime>, Balances>,
+	>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;
 	type AssetLocker = ();

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/lib.rs

@@ -291,7 +291,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/xcm_config.rs

@@ -22,12 +22,12 @@ use super::{
 use crate::bridge_common_config::{DeliveryRewardInBalance, RequiredStakeForStakeAndSlash};
 use frame_support::{
 	parameter_types,
-	traits::{ConstU32, Contains, Equals, Everything, Nothing},
+	traits::{tokens::imbalance::ResolveTo, ConstU32, Contains, Equals, Everything, Nothing},
 };
 use frame_system::EnsureRoot;
+use pallet_collator_selection::StakingPotAccountId;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
 		RelayOrOtherSystemParachains,
@@ -244,8 +244,13 @@ impl xcm_executor::Config for XcmConfig {
 		RuntimeCall,
 		MaxInstructions,
 	>;
-	type Trader =
-		UsingComponents<WeightToFee, WestendLocation, AccountId, Balances, ToStakingPot<Runtime>>;
+	type Trader = UsingComponents<
+		WeightToFee,
+		WestendLocation,
+		AccountId,
+		Balances,
+		ResolveTo<StakingPotAccountId<Runtime>, Balances>,
+	>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;
 	type AssetLocker = ();

cumulus/parachains/runtimes/collectives/collectives-westend/src/lib.rs

@@ -223,7 +223,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
 	type FeeMultiplierUpdate = SlowAdjustingFeeUpdate<Self>;

cumulus/parachains/runtimes/collectives/collectives-westend/src/xcm_config.rs

@@ -20,17 +20,15 @@ use super::{
 };
 use frame_support::{
 	parameter_types,
-	traits::{ConstU32, Contains, Equals, Everything, Nothing},
+	traits::{tokens::imbalance::ResolveTo, ConstU32, Contains, Equals, Everything, Nothing},
 	weights::Weight,
 };
 use frame_system::EnsureRoot;
+use pallet_collator_selection::StakingPotAccountId;
 use pallet_xcm::XcmPassthrough;
-use parachains_common::{
-	impls::ToStakingPot,
-	xcm_config::{
-		AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
-		RelayOrOtherSystemParachains,
-	},
+use parachains_common::xcm_config::{
+	AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
+	RelayOrOtherSystemParachains,
 };
 use polkadot_parachain_primitives::primitives::Sibling;
 use polkadot_runtime_common::xcm_sender::ExponentialPrice;
@@ -268,8 +266,13 @@ impl xcm_executor::Config for XcmConfig {
 	type UniversalLocation = UniversalLocation;
 	type Barrier = Barrier;
 	type Weigher = FixedWeightBounds<TempFixedXcmWeight, RuntimeCall, MaxInstructions>;
-	type Trader =
-		UsingComponents<WeightToFee, WndLocation, AccountId, Balances, ToStakingPot<Runtime>>;
+	type Trader = UsingComponents<
+		WeightToFee,
+		WndLocation,
+		AccountId,
+		Balances,
+		ResolveTo<StakingPotAccountId<Runtime>, Balances>,
+	>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;
 	type AssetClaims = PolkadotXcm;

cumulus/parachains/runtimes/contracts/contracts-rococo/src/lib.rs

@@ -232,7 +232,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type WeightToFee = WeightToFee;
 	/// Relay Chain `TransactionByteFee` / 10
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

cumulus/parachains/runtimes/coretime/coretime-rococo/src/lib.rs

@@ -244,7 +244,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

cumulus/parachains/runtimes/coretime/coretime-rococo/src/xcm_config.rs

@@ -22,12 +22,12 @@ use super::{
 use frame_support::{
 	pallet_prelude::PalletInfoAccess,
 	parameter_types,
-	traits::{ConstU32, Contains, Equals, Everything, Nothing},
+	traits::{tokens::imbalance::ResolveTo, ConstU32, Contains, Equals, Everything, Nothing},
 };
 use frame_system::EnsureRoot;
+use pallet_collator_selection::StakingPotAccountId;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
 		RelayOrOtherSystemParachains,
@@ -237,8 +237,13 @@ impl xcm_executor::Config for XcmConfig {
 		RuntimeCall,
 		MaxInstructions,
 	>;
-	type Trader =
-		UsingComponents<WeightToFee, RocRelayLocation, AccountId, Balances, ToStakingPot<Runtime>>;
+	type Trader = UsingComponents<
+		WeightToFee,
+		RocRelayLocation,
+		AccountId,
+		Balances,
+		ResolveTo<StakingPotAccountId<Runtime>, Balances>,
+	>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;
 	type AssetClaims = PolkadotXcm;

cumulus/parachains/runtimes/coretime/coretime-westend/src/lib.rs

@@ -244,7 +244,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

cumulus/parachains/runtimes/coretime/coretime-westend/src/xcm_config.rs

@@ -22,12 +22,12 @@ use super::{
 use frame_support::{
 	pallet_prelude::PalletInfoAccess,
 	parameter_types,
-	traits::{ConstU32, Contains, Equals, Everything, Nothing},
+	traits::{tokens::imbalance::ResolveTo, ConstU32, Contains, Equals, Everything, Nothing},
 };
 use frame_system::EnsureRoot;
+use pallet_collator_selection::StakingPotAccountId;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
 		RelayOrOtherSystemParachains,
@@ -249,7 +249,7 @@ impl xcm_executor::Config for XcmConfig {
 		TokenRelayLocation,
 		AccountId,
 		Balances,
-		ToStakingPot<Runtime>,
+		ResolveTo<StakingPotAccountId<Runtime>, Balances>,
 	>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;

cumulus/parachains/runtimes/people/people-rococo/src/lib.rs

@@ -225,7 +225,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

cumulus/parachains/runtimes/people/people-rococo/src/xcm_config.rs

@@ -20,12 +20,12 @@ use super::{
 use crate::{TransactionByteFee, CENTS};
 use frame_support::{
 	parameter_types,
-	traits::{ConstU32, Contains, Equals, Everything, Nothing},
+	traits::{tokens::imbalance::ResolveTo, ConstU32, Contains, Equals, Everything, Nothing},
 };
 use frame_system::EnsureRoot;
+use pallet_collator_selection::StakingPotAccountId;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
 		RelayOrOtherSystemParachains,
@@ -249,8 +249,13 @@ impl xcm_executor::Config for XcmConfig {
 		RuntimeCall,
 		MaxInstructions,
 	>;
-	type Trader =
-		UsingComponents<WeightToFee, RelayLocation, AccountId, Balances, ToStakingPot<Runtime>>;
+	type Trader = UsingComponents<
+		WeightToFee,
+		RelayLocation,
+		AccountId,
+		Balances,
+		ResolveTo<StakingPotAccountId<Runtime>, Balances>,
+	>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;
 	type AssetClaims = PolkadotXcm;

cumulus/parachains/runtimes/people/people-westend/src/lib.rs

@@ -225,7 +225,7 @@ parameter_types! {
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction =
-		pallet_transaction_payment::CurrencyAdapter<Balances, DealWithFees<Runtime>>;
+		pallet_transaction_payment::FungibleAdapter<Balances, DealWithFees<Runtime>>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

cumulus/parachains/runtimes/people/people-westend/src/xcm_config.rs

@@ -20,12 +20,12 @@ use super::{
 use crate::{TransactionByteFee, CENTS};
 use frame_support::{
 	parameter_types,
-	traits::{ConstU32, Contains, Equals, Everything, Nothing},
+	traits::{tokens::imbalance::ResolveTo, ConstU32, Contains, Equals, Everything, Nothing},
 };
 use frame_system::EnsureRoot;
+use pallet_collator_selection::StakingPotAccountId;
 use pallet_xcm::XcmPassthrough;
 use parachains_common::{
-	impls::ToStakingPot,
 	xcm_config::{
 		AllSiblingSystemParachains, ConcreteAssetFromSystem, ParentRelayOrSiblingParachains,
 		RelayOrOtherSystemParachains,
@@ -257,8 +257,13 @@ impl xcm_executor::Config for XcmConfig {
 		RuntimeCall,
 		MaxInstructions,
 	>;
-	type Trader =
-		UsingComponents<WeightToFee, RelayLocation, AccountId, Balances, ToStakingPot<Runtime>>;
+	type Trader = UsingComponents<
+		WeightToFee,
+		RelayLocation,
+		AccountId,
+		Balances,
+		ResolveTo<StakingPotAccountId<Runtime>, Balances>,
+	>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;
 	type AssetClaims = PolkadotXcm;

cumulus/parachains/runtimes/testing/penpal/src/lib.rs

@@ -416,7 +416,7 @@ parameter_types! {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = pallet_transaction_payment::CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = pallet_transaction_payment::FungibleAdapter<Balances, ()>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
 	type FeeMultiplierUpdate = SlowAdjustingFeeUpdate<Self>;

cumulus/parachains/runtimes/testing/rococo-parachain/src/lib.rs

@@ -259,7 +259,7 @@ impl pallet_balances::Config for Runtime {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = pallet_transaction_payment::CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = pallet_transaction_payment::FungibleAdapter<Balances, ()>;
 	type WeightToFee = IdentityFee<Balance>;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
 	type FeeMultiplierUpdate = ();

cumulus/test/runtime/src/lib.rs

@@ -241,7 +241,7 @@ impl pallet_balances::Config for Runtime {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = pallet_transaction_payment::CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = pallet_transaction_payment::FungibleAdapter<Balances, ()>;
 	type WeightToFee = IdentityFee<Balance>;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
 	type FeeMultiplierUpdate = ();

polkadot/runtime/common/src/crowdloan/mod.rs

@@ -83,10 +83,6 @@ type CurrencyOf<T> = <<T as Config>::Auctioneer as Auctioneer<BlockNumberFor<T>>
 type LeasePeriodOf<T> = <<T as Config>::Auctioneer as Auctioneer<BlockNumberFor<T>>>::LeasePeriod;
 type BalanceOf<T> = <CurrencyOf<T> as Currency<<T as frame_system::Config>::AccountId>>::Balance;
 
-#[allow(dead_code)]
-type NegativeImbalanceOf<T> =
-	<CurrencyOf<T> as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
-
 type FundIndex = u32;
 
 pub trait WeightInfo {

polkadot/runtime/common/src/impls.rs

@@ -16,8 +16,12 @@
 
 //! Auxiliary `struct`/`enum`s for polkadot runtime.
 
-use crate::NegativeImbalance;
-use frame_support::traits::{Currency, Imbalance, OnUnbalanced};
+use frame_support::traits::{
+	fungible::{Balanced, Credit},
+	tokens::imbalance::ResolveTo,
+	Imbalance, OnUnbalanced,
+};
+use pallet_treasury::TreasuryAccountId;
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
 use primitives::Balance;
 use sp_runtime::{traits::TryConvert, Perquintill, RuntimeDebug};
@@ -25,28 +29,31 @@ use xcm::VersionedLocation;
 
 /// Logic for the author to get a portion of fees.
 pub struct ToAuthor<R>(sp_std::marker::PhantomData<R>);
-impl<R> OnUnbalanced<NegativeImbalance<R>> for ToAuthor<R>
+impl<R> OnUnbalanced<Credit<R::AccountId, pallet_balances::Pallet<R>>> for ToAuthor<R>
 where
 	R: pallet_balances::Config + pallet_authorship::Config,
 	<R as frame_system::Config>::AccountId: From<primitives::AccountId>,
 	<R as frame_system::Config>::AccountId: Into<primitives::AccountId>,
 {
-	fn on_nonzero_unbalanced(amount: NegativeImbalance<R>) {
+	fn on_nonzero_unbalanced(
+		amount: Credit<<R as frame_system::Config>::AccountId, pallet_balances::Pallet<R>>,
+	) {
 		if let Some(author) = <pallet_authorship::Pallet<R>>::author() {
-			<pallet_balances::Pallet<R>>::resolve_creating(&author, amount);
+			let _ = <pallet_balances::Pallet<R>>::resolve(&author, amount);
 		}
 	}
 }
 
 pub struct DealWithFees<R>(sp_std::marker::PhantomData<R>);
-impl<R> OnUnbalanced<NegativeImbalance<R>> for DealWithFees<R>
+impl<R> OnUnbalanced<Credit<R::AccountId, pallet_balances::Pallet<R>>> for DealWithFees<R>
 where
-	R: pallet_balances::Config + pallet_treasury::Config + pallet_authorship::Config,
-	pallet_treasury::Pallet<R>: OnUnbalanced<NegativeImbalance<R>>,
+	R: pallet_balances::Config + pallet_authorship::Config + pallet_treasury::Config,
 	<R as frame_system::Config>::AccountId: From<primitives::AccountId>,
 	<R as frame_system::Config>::AccountId: Into<primitives::AccountId>,
 {
-	fn on_unbalanceds<B>(mut fees_then_tips: impl Iterator<Item = NegativeImbalance<R>>) {
+	fn on_unbalanceds<B>(
+		mut fees_then_tips: impl Iterator<Item = Credit<R::AccountId, pallet_balances::Pallet<R>>>,
+	) {
 		if let Some(fees) = fees_then_tips.next() {
 			// for fees, 80% to treasury, 20% to author
 			let mut split = fees.ration(80, 20);
@@ -54,8 +61,7 @@ where
 				// for tips, if any, 100% to author
 				tips.merge_into(&mut split.1);
 			}
-			use pallet_treasury::Pallet as Treasury;
-			<Treasury<R> as OnUnbalanced<_>>::on_unbalanced(split.0);
+			ResolveTo::<TreasuryAccountId<R>, pallet_balances::Pallet<R>>::on_unbalanced(split.0);
 			<ToAuthor<R> as OnUnbalanced<_>>::on_unbalanced(split.1);
 		}
 	}
@@ -366,8 +372,14 @@ mod tests {
 	#[test]
 	fn test_fees_and_tip_split() {
 		new_test_ext().execute_with(|| {
-			let fee = Balances::issue(10);
-			let tip = Balances::issue(20);
+			let fee =
+				<pallet_balances::Pallet<Test> as frame_support::traits::fungible::Balanced<
+					AccountId,
+				>>::issue(10);
+			let tip =
+				<pallet_balances::Pallet<Test> as frame_support::traits::fungible::Balanced<
+					AccountId,
+				>>::issue(20);
 
 			assert_eq!(Balances::free_balance(Treasury::account_id()), 0);
 			assert_eq!(Balances::free_balance(TEST_ACCOUNT), 0);

polkadot/runtime/common/src/lib.rs

@@ -63,6 +63,9 @@ pub use sp_runtime::BuildStorage;
 /// Implementations of some helper traits passed into runtime modules as associated types.
 pub use impls::ToAuthor;
 
+#[deprecated(
+	note = "Please use fungible::Credit instead. This type will be removed some time after March 2024."
+)]
 pub type NegativeImbalance<T> = <pallet_balances::Pallet<T> as Currency<
 	<T as frame_system::Config>::AccountId,
 >>::NegativeImbalance;

polkadot/runtime/rococo/src/lib.rs

@@ -79,7 +79,7 @@ use frame_system::{EnsureRoot, EnsureSigned};
 use pallet_grandpa::{fg_primitives, AuthorityId as GrandpaId};
 use pallet_identity::legacy::IdentityInfo;
 use pallet_session::historical as session_historical;
-use pallet_transaction_payment::{CurrencyAdapter, FeeDetails, RuntimeDispatchInfo};
+use pallet_transaction_payment::{FeeDetails, FungibleAdapter, RuntimeDispatchInfo};
 use sp_core::{ConstU128, OpaqueMetadata, H256};
 use sp_runtime::{
 	create_runtime_str, generic, impl_opaque_keys,
@@ -324,7 +324,7 @@ parameter_types! {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, ToAuthor<Runtime>>;
+	type OnChargeTransaction = FungibleAdapter<Balances, ToAuthor<Runtime>>;
 	type OperationalFeeMultiplier = OperationalFeeMultiplier;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

polkadot/runtime/test-runtime/src/lib.rs

@@ -20,7 +20,7 @@
 // `construct_runtime!` does a lot of recursion and requires us to increase the limit to 256.
 #![recursion_limit = "256"]
 
-use pallet_transaction_payment::CurrencyAdapter;
+use pallet_transaction_payment::FungibleAdapter;
 use parity_scale_codec::Encode;
 use sp_std::{collections::btree_map::BTreeMap, prelude::*};
 
@@ -233,7 +233,7 @@ parameter_types! {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = FungibleAdapter<Balances, ()>;
 	type OperationalFeeMultiplier = OperationalFeeMultiplier;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = frame_support::weights::ConstantMultiplier<Balance, TransactionByteFee>;

polkadot/runtime/westend/src/lib.rs

@@ -42,7 +42,7 @@ use frame_system::{EnsureRoot, EnsureSigned};
 use pallet_grandpa::{fg_primitives, AuthorityId as GrandpaId};
 use pallet_identity::legacy::IdentityInfo;
 use pallet_session::historical as session_historical;
-use pallet_transaction_payment::{CurrencyAdapter, FeeDetails, RuntimeDispatchInfo};
+use pallet_transaction_payment::{FeeDetails, FungibleAdapter, RuntimeDispatchInfo};
 use parity_scale_codec::{Decode, Encode, MaxEncodedLen};
 use primitives::{
 	slashing, AccountId, AccountIndex, ApprovalVotingParams, Balance, BlockNumber, CandidateEvent,
@@ -377,7 +377,7 @@ parameter_types! {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, ToAuthor<Runtime>>;
+	type OnChargeTransaction = FungibleAdapter<Balances, ToAuthor<Runtime>>;
 	type OperationalFeeMultiplier = OperationalFeeMultiplier;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

polkadot/xcm/xcm-builder/src/weight.rs

@@ -16,7 +16,10 @@
 
 use frame_support::{
 	dispatch::GetDispatchInfo,
-	traits::{tokens::currency::Currency as CurrencyT, Get, OnUnbalanced as OnUnbalancedT},
+	traits::{
+		fungible::{Balanced, Credit, Inspect},
+		Get, OnUnbalanced as OnUnbalancedT,
+	},
 	weights::{
 		constants::{WEIGHT_PROOF_SIZE_PER_MB, WEIGHT_REF_TIME_PER_SECOND},
 		WeightToFee as WeightToFeeT,
@@ -193,23 +196,23 @@ impl<T: Get<(AssetId, u128, u128)>, R: TakeRevenue> Drop for FixedRateOfFungible
 /// Weight trader which uses the configured `WeightToFee` to set the right price for weight and then
 /// places any weight bought into the right account.
 pub struct UsingComponents<
-	WeightToFee: WeightToFeeT<Balance = Currency::Balance>,
+	WeightToFee: WeightToFeeT<Balance = <Fungible as Inspect<AccountId>>::Balance>,
 	AssetIdValue: Get<Location>,
 	AccountId,
-	Currency: CurrencyT<AccountId>,
-	OnUnbalanced: OnUnbalancedT<Currency::NegativeImbalance>,
+	Fungible: Balanced<AccountId> + Inspect<AccountId>,
+	OnUnbalanced: OnUnbalancedT<Credit<AccountId, Fungible>>,
 >(
 	Weight,
-	Currency::Balance,
-	PhantomData<(WeightToFee, AssetIdValue, AccountId, Currency, OnUnbalanced)>,
+	Fungible::Balance,
+	PhantomData<(WeightToFee, AssetIdValue, AccountId, Fungible, OnUnbalanced)>,
 );
 impl<
-		WeightToFee: WeightToFeeT<Balance = Currency::Balance>,
+		WeightToFee: WeightToFeeT<Balance = <Fungible as Inspect<AccountId>>::Balance>,
 		AssetIdValue: Get<Location>,
 		AccountId,
-		Currency: CurrencyT<AccountId>,
-		OnUnbalanced: OnUnbalancedT<Currency::NegativeImbalance>,
-	> WeightTrader for UsingComponents<WeightToFee, AssetIdValue, AccountId, Currency, OnUnbalanced>
+		Fungible: Balanced<AccountId> + Inspect<AccountId>,
+		OnUnbalanced: OnUnbalancedT<Credit<AccountId, Fungible>>,
+	> WeightTrader for UsingComponents<WeightToFee, AssetIdValue, AccountId, Fungible, OnUnbalanced>
 {
 	fn new() -> Self {
 		Self(Weight::zero(), Zero::zero(), PhantomData)
@@ -247,14 +250,14 @@ impl<
 	}
 }
 impl<
-		WeightToFee: WeightToFeeT<Balance = Currency::Balance>,
+		WeightToFee: WeightToFeeT<Balance = <Fungible as Inspect<AccountId>>::Balance>,
 		AssetId: Get<Location>,
 		AccountId,
-		Currency: CurrencyT<AccountId>,
-		OnUnbalanced: OnUnbalancedT<Currency::NegativeImbalance>,
-	> Drop for UsingComponents<WeightToFee, AssetId, AccountId, Currency, OnUnbalanced>
+		Fungible: Balanced<AccountId> + Inspect<AccountId>,
+		OnUnbalanced: OnUnbalancedT<Credit<AccountId, Fungible>>,
+	> Drop for UsingComponents<WeightToFee, AssetId, AccountId, Fungible, OnUnbalanced>
 {
 	fn drop(&mut self) {
-		OnUnbalanced::on_unbalanced(Currency::issue(self.1));
+		OnUnbalanced::on_unbalanced(Fungible::issue(self.1));
 	}
 }

prdoc/pr_2292.prdoc

@@ -0,0 +1,59 @@
+title: Migrate Fee Payment from Currency to fungible traits
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      Deprecates the `CurrencyAdapter` and introduces `FungibleAdapter`
+      Deprecates `ToStakingPot` and replaces usage with `ResolveTo`
+      Updated `DealWithFees`, `ToAuthor`, `AssetsToBlockAuthor` to all use `fungible` traits
+      Updated runtime XCM Weight Traders to use `ResolveTo`
+      Updated runtime TransactionPayment pallets to use `FungibleAdapter` instead of `CurrencyAdapter`
+
+      Runtime Migration Guide:
+      - Replace usage of `CurrencyAdapter` with `FungibleAdapter`
+      - Replace usage of `ToStakingPot<Runtime>` with `ResolveTo<pallet_collator_selection::StakingPotAccountId<Runtime>, Balances>`
+
+crates:
+  - name: pallet-collator-selection
+    bump: minor
+  - name: parachains-common
+    bump: major
+  - name: asset-hub-rococo-runtime
+    bump: major
+  - name: asset-hub-westend-runtime
+    bump: major
+  - name: bridge-hub-westend-runtime
+    bump: major
+  - name: bridge-hub-rococo-runtime
+    bump: major
+  - name: collectives-westend-runtime
+    bump: major
+  - name: contracts-rococo-runtime
+    bump: major
+  - name: coretime-rococo-runtime
+    bump: major
+  - name: coretime-westend-runtime
+    bump: major
+  - name: people-westend-runtime
+    bump: major
+  - name: people-rococo-runtime
+    bump: major
+  - name: polkadot-runtime-common
+    bump: major
+  - name: westend-runtime
+    bump: major
+  - name: rococo-runtime
+    bump: major
+  - name: staging-xcm-builder
+    bump: major
+  - name: kitchensink-runtime
+    bump: major
+  - name: pallet-transaction-payment
+    bump: minor
+  - name: minimal-template-runtime
+    bump: major
+  - name: parachain-template-runtime
+    bump: major
+  - name: solochain-template-runtime
+    bump: major
+

substrate/bin/node/runtime/src/lib.rs

@@ -71,6 +71,9 @@ use pallet_im_online::sr25519::AuthorityId as ImOnlineId;
 use pallet_nfts::PalletFeatures;
 use pallet_nis::WithMaximumOf;
 use pallet_session::historical as pallet_session_historical;
+// Can't use `FungibleAdapter` here until Treasury pallet migrates to fungibles
+// <https://github.com/paritytech/polkadot-sdk/issues/226>
+#[allow(deprecated)]
 pub use pallet_transaction_payment::{CurrencyAdapter, Multiplier, TargetedFeeAdjustment};
 use pallet_transaction_payment::{FeeDetails, RuntimeDispatchInfo};
 use pallet_tx_pause::RuntimeCallNameOf;
@@ -549,6 +552,9 @@ parameter_types! {
 	pub MaximumMultiplier: Multiplier = Bounded::max_value();
 }
 
+// Can't use `FungibleAdapter` here until Treasury pallet migrates to fungibles
+// <https://github.com/paritytech/polkadot-sdk/issues/226>
+#[allow(deprecated)]
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type OnChargeTransaction = CurrencyAdapter<Balances, DealWithFees>;

substrate/frame/balances/src/tests/mod.rs

@@ -32,7 +32,7 @@ use frame_support::{
 	weights::{IdentityFee, Weight},
 };
 use frame_system::{self as system, RawOrigin};
-use pallet_transaction_payment::{ChargeTransactionPayment, CurrencyAdapter, Multiplier};
+use pallet_transaction_payment::{ChargeTransactionPayment, FungibleAdapter, Multiplier};
 use scale_info::TypeInfo;
 use sp_core::hexdisplay::HexDisplay;
 use sp_io;
@@ -99,7 +99,7 @@ impl frame_system::Config for Test {
 #[derive_impl(pallet_transaction_payment::config_preludes::TestDefaultConfig)]
 impl pallet_transaction_payment::Config for Test {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Pallet<Test>, ()>;
+	type OnChargeTransaction = FungibleAdapter<Pallet<Test>, ()>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = IdentityFee<u64>;
 	type LengthToFee = IdentityFee<u64>;

substrate/frame/executive/src/tests.rs

@@ -19,6 +19,7 @@
 
 use super::*;
 
+use pallet_transaction_payment::FungibleAdapter;
 use sp_core::H256;
 use sp_runtime::{
 	generic::{DigestItem, Era},
@@ -40,7 +41,6 @@ use frame_support::{
 };
 use frame_system::{pallet_prelude::*, ChainContext, LastRuntimeUpgrade, LastRuntimeUpgradeInfo};
 use pallet_balances::Call as BalancesCall;
-use pallet_transaction_payment::CurrencyAdapter;
 
 const TEST_KEY: &[u8] = b":test:key:";
 
@@ -338,7 +338,7 @@ parameter_types! {
 }
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = FungibleAdapter<Balances, ()>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = IdentityFee<Balance>;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;

substrate/frame/transaction-payment/asset-conversion-tx-payment/src/mock.rs

@@ -24,6 +24,7 @@ use frame_support::{
 	pallet_prelude::*,
 	parameter_types,
 	traits::{
+		fungible,
 		tokens::{
 			fungible::{NativeFromLeft, NativeOrWithId, UnionOf},
 			imbalance::ResolveAssetTo,
@@ -36,7 +37,7 @@ use frame_support::{
 use frame_system as system;
 use frame_system::{EnsureRoot, EnsureSignedBy};
 use pallet_asset_conversion::{Ascending, Chain, WithFirstAsset};
-use pallet_transaction_payment::CurrencyAdapter;
+use pallet_transaction_payment::FungibleAdapter;
 use sp_core::H256;
 use sp_runtime::{
 	traits::{AccountIdConversion, BlakeTwo256, IdentityLookup, SaturatedConversion},
@@ -155,9 +156,13 @@ parameter_types! {
 }
 
 pub struct DealWithFees;
-impl OnUnbalanced<pallet_balances::NegativeImbalance<Runtime>> for DealWithFees {
+impl OnUnbalanced<fungible::Credit<<Runtime as frame_system::Config>::AccountId, Balances>>
+	for DealWithFees
+{
 	fn on_unbalanceds<B>(
-		mut fees_then_tips: impl Iterator<Item = pallet_balances::NegativeImbalance<Runtime>>,
+		mut fees_then_tips: impl Iterator<
+			Item = fungible::Credit<<Runtime as frame_system::Config>::AccountId, Balances>,
+		>,
 	) {
 		if let Some(fees) = fees_then_tips.next() {
 			FeeUnbalancedAmount::mutate(|a| *a += fees.peek());
@@ -171,7 +176,7 @@ impl OnUnbalanced<pallet_balances::NegativeImbalance<Runtime>> for DealWithFees
 #[derive_impl(pallet_transaction_payment::config_preludes::TestDefaultConfig)]
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, DealWithFees>;
+	type OnChargeTransaction = FungibleAdapter<Balances, DealWithFees>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = TransactionByteFee;
 	type FeeMultiplierUpdate = ();

substrate/frame/transaction-payment/asset-tx-payment/src/mock.rs

@@ -28,7 +28,7 @@ use frame_support::{
 };
 use frame_system as system;
 use frame_system::EnsureRoot;
-use pallet_transaction_payment::CurrencyAdapter;
+use pallet_transaction_payment::FungibleAdapter;
 use sp_core::H256;
 use sp_runtime::traits::{BlakeTwo256, ConvertInto, IdentityLookup, SaturatedConversion};
 
@@ -139,7 +139,7 @@ impl WeightToFeeT for TransactionByteFee {
 #[derive_impl(pallet_transaction_payment::config_preludes::TestDefaultConfig)]
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = FungibleAdapter<Balances, ()>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = TransactionByteFee;
 	type FeeMultiplierUpdate = ();

substrate/frame/transaction-payment/src/mock.rs

@@ -25,7 +25,7 @@ use frame_support::{
 	derive_impl,
 	dispatch::DispatchClass,
 	parameter_types,
-	traits::{ConstU32, ConstU64, Imbalance, OnUnbalanced},
+	traits::{fungible, ConstU32, ConstU64, Imbalance, OnUnbalanced},
 	weights::{Weight, WeightToFee as WeightToFeeT},
 };
 use frame_system as system;
@@ -137,9 +137,13 @@ parameter_types! {
 }
 
 pub struct DealWithFees;
-impl OnUnbalanced<pallet_balances::NegativeImbalance<Runtime>> for DealWithFees {
+impl OnUnbalanced<fungible::Credit<<Runtime as frame_system::Config>::AccountId, Balances>>
+	for DealWithFees
+{
 	fn on_unbalanceds<B>(
-		mut fees_then_tips: impl Iterator<Item = pallet_balances::NegativeImbalance<Runtime>>,
+		mut fees_then_tips: impl Iterator<
+			Item = fungible::Credit<<Runtime as frame_system::Config>::AccountId, Balances>,
+		>,
 	) {
 		if let Some(fees) = fees_then_tips.next() {
 			FeeUnbalancedAmount::mutate(|a| *a += fees.peek());
@@ -152,7 +156,7 @@ impl OnUnbalanced<pallet_balances::NegativeImbalance<Runtime>> for DealWithFees
 
 impl Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, DealWithFees>;
+	type OnChargeTransaction = FungibleAdapter<Balances, DealWithFees>;
 	type OperationalFeeMultiplier = OperationalFeeMultiplier;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = TransactionByteFee;

substrate/frame/transaction-payment/src/payment.rs

@@ -25,7 +25,11 @@ use sp_runtime::{
 };
 
 use frame_support::{
-	traits::{Currency, ExistenceRequirement, Imbalance, OnUnbalanced, WithdrawReasons},
+	traits::{
+		fungible::{Balanced, Credit, Debt, Inspect},
+		tokens::Precision,
+		Currency, ExistenceRequirement, Imbalance, OnUnbalanced, WithdrawReasons,
+	},
 	unsigned::TransactionValidityError,
 };
 
@@ -66,18 +70,95 @@ pub trait OnChargeTransaction<T: Config> {
 	) -> Result<(), TransactionValidityError>;
 }
 
-/// Implements the transaction payment for a pallet implementing the `Currency`
-/// trait (eg. the pallet_balances) using an unbalance handler (implementing
-/// `OnUnbalanced`).
+/// Implements transaction payment for a pallet implementing the [`frame_support::traits::fungible`]
+/// trait (eg. pallet_balances) using an unbalance handler (implementing
+/// [`OnUnbalanced`]).
 ///
-/// The unbalance handler is given 2 unbalanceds in [`OnUnbalanced::on_unbalanceds`]: fee and
-/// then tip.
+/// The unbalance handler is given 2 unbalanceds in [`OnUnbalanced::on_unbalanceds`]: `fee` and
+/// then `tip`.
+pub struct FungibleAdapter<F, OU>(PhantomData<(F, OU)>);
+
+impl<T, F, OU> OnChargeTransaction<T> for FungibleAdapter<F, OU>
+where
+	T: Config,
+	F: Balanced<T::AccountId>,
+	OU: OnUnbalanced<Credit<T::AccountId, F>>,
+{
+	type LiquidityInfo = Option<Credit<T::AccountId, F>>;
+	type Balance = <F as Inspect<<T as frame_system::Config>::AccountId>>::Balance;
+
+	fn withdraw_fee(
+		who: &<T>::AccountId,
+		_call: &<T>::RuntimeCall,
+		_dispatch_info: &DispatchInfoOf<<T>::RuntimeCall>,
+		fee: Self::Balance,
+		_tip: Self::Balance,
+	) -> Result<Self::LiquidityInfo, TransactionValidityError> {
+		if fee.is_zero() {
+			return Ok(None)
+		}
+
+		match F::withdraw(
+			who,
+			fee,
+			Precision::Exact,
+			frame_support::traits::tokens::Preservation::Preserve,
+			frame_support::traits::tokens::Fortitude::Polite,
+		) {
+			Ok(imbalance) => Ok(Some(imbalance)),
+			Err(_) => Err(InvalidTransaction::Payment.into()),
+		}
+	}
+
+	fn correct_and_deposit_fee(
+		who: &<T>::AccountId,
+		_dispatch_info: &DispatchInfoOf<<T>::RuntimeCall>,
+		_post_info: &PostDispatchInfoOf<<T>::RuntimeCall>,
+		corrected_fee: Self::Balance,
+		tip: Self::Balance,
+		already_withdrawn: Self::LiquidityInfo,
+	) -> Result<(), TransactionValidityError> {
+		if let Some(paid) = already_withdrawn {
+			// Calculate how much refund we should return
+			let refund_amount = paid.peek().saturating_sub(corrected_fee);
+			// refund to the the account that paid the fees if it exists. otherwise, don't refind
+			// anything.
+			let refund_imbalance = if F::total_balance(who) > F::Balance::zero() {
+				F::deposit(who, refund_amount, Precision::BestEffort)
+					.unwrap_or_else(|_| Debt::<T::AccountId, F>::zero())
+			} else {
+				Debt::<T::AccountId, F>::zero()
+			};
+			// merge the imbalance caused by paying the fees and refunding parts of it again.
+			let adjusted_paid: Credit<T::AccountId, F> = paid
+				.offset(refund_imbalance)
+				.same()
+				.map_err(|_| TransactionValidityError::Invalid(InvalidTransaction::Payment))?;
+			// Call someone else to handle the imbalance (fee and tip separately)
+			let (tip, fee) = adjusted_paid.split(tip);
+			OU::on_unbalanceds(Some(fee).into_iter().chain(Some(tip)));
+		}
+
+		Ok(())
+	}
+}
+
+/// Implements the transaction payment for a pallet implementing the [`Currency`]
+/// trait (eg. the pallet_balances) using an unbalance handler (implementing
+/// [`OnUnbalanced`]).
+///
+/// The unbalance handler is given 2 unbalanceds in [`OnUnbalanced::on_unbalanceds`]: `fee` and
+/// then `tip`.
+#[deprecated(
+	note = "Please use the fungible trait and FungibleAdapter. This struct will be removed some time after March 2024."
+)]
 pub struct CurrencyAdapter<C, OU>(PhantomData<(C, OU)>);
 
 /// Default implementation for a Currency and an OnUnbalanced handler.
 ///
-/// The unbalance handler is given 2 unbalanceds in [`OnUnbalanced::on_unbalanceds`]: fee and
-/// then tip.
+/// The unbalance handler is given 2 unbalanceds in [`OnUnbalanced::on_unbalanceds`]: `fee` and
+/// then `tip`.
+#[allow(deprecated)]
 impl<T, C, OU> OnChargeTransaction<T> for CurrencyAdapter<C, OU>
 where
 	T: Config,

substrate/frame/treasury/src/lib.rs

@@ -76,6 +76,8 @@ mod benchmarking;
 #[cfg(test)]
 mod tests;
 pub mod weights;
+use core::marker::PhantomData;
+
 #[cfg(feature = "runtime-benchmarks")]
 pub use benchmarking::ArgumentsFactory;
 
@@ -1120,3 +1122,15 @@ impl<T: Config<I>, I: 'static> OnUnbalanced<NegativeImbalanceOf<T, I>> for Palle
 		Self::deposit_event(Event::Deposit { value: numeric_amount });
 	}
 }
+
+/// TypedGet implementaion to get the AccountId of the Treasury.
+pub struct TreasuryAccountId<R>(PhantomData<R>);
+impl<R> sp_runtime::traits::TypedGet for TreasuryAccountId<R>
+where
+	R: crate::Config,
+{
+	type Type = <R as frame_system::Config>::AccountId;
+	fn get() -> Self::Type {
+		<crate::Pallet<R>>::account_id()
+	}
+}

templates/minimal/runtime/src/lib.rs

@@ -104,7 +104,7 @@ impl pallet_timestamp::Config for Runtime {}
 
 #[derive_impl(pallet_transaction_payment::config_preludes::TestDefaultConfig)]
 impl pallet_transaction_payment::Config for Runtime {
-	type OnChargeTransaction = pallet_transaction_payment::CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = pallet_transaction_payment::FungibleAdapter<Balances, ()>;
 	type WeightToFee = NoFee<<Self as pallet_balances::Config>::Balance>;
 	type LengthToFee = FixedFee<1, <Self as pallet_balances::Config>::Balance>;
 }

templates/parachain/runtime/src/configs/mod.rs

@@ -166,7 +166,7 @@ parameter_types! {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = pallet_transaction_payment::CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = pallet_transaction_payment::FungibleAdapter<Balances, ()>;
 	type WeightToFee = WeightToFee;
 	type LengthToFee = ConstantMultiplier<Balance, TransactionByteFee>;
 	type FeeMultiplierUpdate = SlowAdjustingFeeUpdate<Self>;

templates/solochain/runtime/src/lib.rs

@@ -36,7 +36,7 @@ pub use frame_support::{
 pub use frame_system::Call as SystemCall;
 pub use pallet_balances::Call as BalancesCall;
 pub use pallet_timestamp::Call as TimestampCall;
-use pallet_transaction_payment::{ConstFeeMultiplier, CurrencyAdapter, Multiplier};
+use pallet_transaction_payment::{ConstFeeMultiplier, FungibleAdapter, Multiplier};
 #[cfg(any(feature = "std", test))]
 pub use sp_runtime::BuildStorage;
 pub use sp_runtime::{Perbill, Permill};
@@ -230,7 +230,7 @@ parameter_types! {
 
 impl pallet_transaction_payment::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
-	type OnChargeTransaction = CurrencyAdapter<Balances, ()>;
+	type OnChargeTransaction = FungibleAdapter<Balances, ()>;
 	type OperationalFeeMultiplier = ConstU8<5>;
 	type WeightToFee = IdentityFee<Balance>;
 	type LengthToFee = IdentityFee<Balance>;