Add FixedPointOperand blanket implementation (#14634)

* bound `Balance` to `FixedPointOperand`

* ".git/.scripts/commands/fmt/fmt.sh"

* clean up code

* Apply suggestions from code review

Co-authored-by: Gavin Wood <gavin@parity.io>

* wip

* add blanket `FixedPointOperand` impl

* update nis CurrencyBalance

* remove CheckedNeg bound

---------

Co-authored-by: command-bot <>
Co-authored-by: Gavin Wood <gavin@parity.io>

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

@@ -1141,7 +1141,6 @@ impl pallet_asset_rate::Config for Runtime {
 	type CreateOrigin = EnsureRoot<AccountId>;
 	type RemoveOrigin = EnsureRoot<AccountId>;
 	type UpdateOrigin = EnsureRoot<AccountId>;
-	type Balance = Balance;
 	type Currency = Balances;
 	type AssetKind = u32;
 	type RuntimeEvent = RuntimeEvent;

substrate/frame/asset-rate/src/lib.rs

@@ -59,11 +59,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use frame_support::traits::{
-	fungible::Inspect,
-	tokens::{Balance, ConversionFromAssetBalance},
-};
-use sp_runtime::{traits::Zero, FixedPointNumber, FixedPointOperand, FixedU128};
+use frame_support::traits::{fungible::Inspect, tokens::ConversionFromAssetBalance};
+use sp_runtime::{traits::Zero, FixedPointNumber, FixedU128};
 
 pub use pallet::*;
 pub use weights::WeightInfo;
@@ -111,11 +108,8 @@ pub mod pallet {
 		/// The origin permissioned to update an existiing conversion rate for an asset.
 		type UpdateOrigin: EnsureOrigin<Self::RuntimeOrigin>;
 
-		/// The units in which we record balances.
-		type Balance: Balance + FixedPointOperand;
-
 		/// The currency mechanism for this pallet.
-		type Currency: Inspect<Self::AccountId, Balance = Self::Balance>;
+		type Currency: Inspect<Self::AccountId>;
 
 		/// The type for asset kinds for which the conversion rate to native balance is set.
 		type AssetKind: Parameter + MaxEncodedLen;
@@ -230,7 +224,6 @@ pub mod pallet {
 impl<T> ConversionFromAssetBalance<BalanceOf<T>, AssetKindOf<T>, BalanceOf<T>> for Pallet<T>
 where
 	T: Config,
-	BalanceOf<T>: FixedPointOperand + Zero,
 {
 	type Error = pallet::Error<T>;
 

substrate/frame/asset-rate/src/mock.rs

@@ -84,7 +84,6 @@ impl pallet_asset_rate::Config for Test {
 	type CreateOrigin = frame_system::EnsureRoot<u64>;
 	type RemoveOrigin = frame_system::EnsureRoot<u64>;
 	type UpdateOrigin = frame_system::EnsureRoot<u64>;
-	type Balance = u64;
 	type Currency = Balances;
 	type AssetKind = u32;
 	#[cfg(feature = "runtime-benchmarks")]

substrate/frame/assets/src/types.rs

@@ -22,7 +22,7 @@ use frame_support::{
 	pallet_prelude::*,
 	traits::{fungible, tokens::ConversionToAssetBalance},
 };
-use sp_runtime::{traits::Convert, FixedPointNumber, FixedPointOperand, FixedU128};
+use sp_runtime::{traits::Convert, FixedPointNumber, FixedU128};
 
 pub(super) type DepositBalanceOf<T, I = ()> =
 	<<T as Config<I>>::Currency as Currency<<T as SystemConfig>::AccountId>>::Balance;
@@ -293,8 +293,6 @@ where
 	T: Config<I>,
 	I: 'static,
 	CON: Convert<BalanceOf<F, T>, AssetBalanceOf<T, I>>,
-	BalanceOf<F, T>: FixedPointOperand + Zero,
-	AssetBalanceOf<T, I>: FixedPointOperand + Zero,
 {
 	type Error = ConversionError;
 

substrate/frame/nis/src/lib.rs

@@ -165,6 +165,7 @@ pub mod pallet {
 			fungible::{self, hold::Mutate as FunHoldMutate, Balanced as FunBalanced},
 			nonfungible::{Inspect as NftInspect, Transfer as NftTransfer},
 			tokens::{
+				Balance,
 				Fortitude::Polite,
 				Precision::{BestEffort, Exact},
 				Preservation::Expendable,
@@ -214,17 +215,9 @@ pub mod pallet {
 		/// Overarching hold reason.
 		type RuntimeHoldReason: From<HoldReason>;
 
-		/// Just the `Currency::Balance` type; we have this item to allow us to constrain it to
-		/// `From<u64>`.
-		type CurrencyBalance: sp_runtime::traits::AtLeast32BitUnsigned
-			+ codec::FullCodec
-			+ Copy
-			+ MaybeSerializeDeserialize
-			+ sp_std::fmt::Debug
-			+ Default
-			+ From<u64>
-			+ TypeInfo
-			+ MaxEncodedLen;
+		/// Just the [`Balance`] type; we have this item to allow us to constrain it to
+		/// [`From<u64>`].
+		type CurrencyBalance: Balance + From<u64>;
 
 		/// Origin required for auto-funding the deficit.
 		type FundOrigin: EnsureOrigin<Self::RuntimeOrigin>;

substrate/frame/support/src/traits/tokens/currency.rs

@@ -25,9 +25,7 @@ use crate::{
 	dispatch::{DispatchError, DispatchResult},
 	traits::Get,
 };
-use codec::MaxEncodedLen;
-use sp_runtime::{traits::MaybeSerializeDeserialize, FixedPointOperand};
-use sp_std::fmt::Debug;
+use sp_runtime::traits::MaybeSerializeDeserialize;
 
 mod reservable;
 pub use reservable::{NamedReservableCurrency, ReservableCurrency};
@@ -37,7 +35,7 @@ pub use lockable::{LockIdentifier, LockableCurrency, VestingSchedule};
 /// Abstraction over a fungible assets system.
 pub trait Currency<AccountId> {
 	/// The balance of an account.
-	type Balance: Balance + MaybeSerializeDeserialize + Debug + MaxEncodedLen + FixedPointOperand;
+	type Balance: Balance + MaybeSerializeDeserialize;
 
 	/// The opaque token type for an imbalance. This is returned by unbalanced operations
 	/// and must be dealt with. It may be dropped but cannot be cloned.

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

@@ -60,7 +60,6 @@ use sp_runtime::{
 	transaction_validity::{
 		InvalidTransaction, TransactionValidity, TransactionValidityError, ValidTransaction,
 	},
-	FixedPointOperand,
 };
 
 #[cfg(test)]
@@ -165,12 +164,8 @@ pub struct ChargeAssetTxPayment<T: Config> {
 impl<T: Config> ChargeAssetTxPayment<T>
 where
 	T::RuntimeCall: Dispatchable<Info = DispatchInfo, PostInfo = PostDispatchInfo>,
-	AssetBalanceOf<T>: Send + Sync + FixedPointOperand,
-	BalanceOf<T>: Send
-		+ Sync
-		+ FixedPointOperand
-		+ Into<ChargeAssetBalanceOf<T>>
-		+ From<ChargeAssetLiquidityOf<T>>,
+	AssetBalanceOf<T>: Send + Sync,
+	BalanceOf<T>: Send + Sync + Into<ChargeAssetBalanceOf<T>> + From<ChargeAssetLiquidityOf<T>>,
 	ChargeAssetIdOf<T>: Send + Sync,
 {
 	/// Utility constructor. Used only in client/factory code.
@@ -234,11 +229,10 @@ impl<T: Config> sp_std::fmt::Debug for ChargeAssetTxPayment<T> {
 impl<T: Config> SignedExtension for ChargeAssetTxPayment<T>
 where
 	T::RuntimeCall: Dispatchable<Info = DispatchInfo, PostInfo = PostDispatchInfo>,
-	AssetBalanceOf<T>: Send + Sync + FixedPointOperand,
+	AssetBalanceOf<T>: Send + Sync,
 	BalanceOf<T>: Send
 		+ Sync
 		+ From<u64>
-		+ FixedPointOperand
 		+ Into<ChargeAssetBalanceOf<T>>
 		+ Into<ChargeAssetLiquidityOf<T>>
 		+ From<ChargeAssetLiquidityOf<T>>,

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

@@ -56,7 +56,6 @@ use sp_runtime::{
 	transaction_validity::{
 		InvalidTransaction, TransactionValidity, TransactionValidityError, ValidTransaction,
 	},
-	FixedPointOperand,
 };
 
 #[cfg(test)]
@@ -156,8 +155,8 @@ pub struct ChargeAssetTxPayment<T: Config> {
 impl<T: Config> ChargeAssetTxPayment<T>
 where
 	T::RuntimeCall: Dispatchable<Info = DispatchInfo, PostInfo = PostDispatchInfo>,
-	AssetBalanceOf<T>: Send + Sync + FixedPointOperand,
-	BalanceOf<T>: Send + Sync + FixedPointOperand + IsType<ChargeAssetBalanceOf<T>>,
+	AssetBalanceOf<T>: Send + Sync,
+	BalanceOf<T>: Send + Sync + IsType<ChargeAssetBalanceOf<T>>,
 	ChargeAssetIdOf<T>: Send + Sync,
 	Credit<T::AccountId, T::Fungibles>: IsType<ChargeAssetLiquidityOf<T>>,
 {
@@ -213,8 +212,8 @@ impl<T: Config> sp_std::fmt::Debug for ChargeAssetTxPayment<T> {
 impl<T: Config> SignedExtension for ChargeAssetTxPayment<T>
 where
 	T::RuntimeCall: Dispatchable<Info = DispatchInfo, PostInfo = PostDispatchInfo>,
-	AssetBalanceOf<T>: Send + Sync + FixedPointOperand,
-	BalanceOf<T>: Send + Sync + From<u64> + FixedPointOperand + IsType<ChargeAssetBalanceOf<T>>,
+	AssetBalanceOf<T>: Send + Sync,
+	BalanceOf<T>: Send + Sync + From<u64> + IsType<ChargeAssetBalanceOf<T>>,
 	ChargeAssetIdOf<T>: Send + Sync,
 	Credit<T::AccountId, T::Fungibles>: IsType<ChargeAssetLiquidityOf<T>>,
 {

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

@@ -67,7 +67,7 @@ use sp_runtime::{
 	transaction_validity::{
 		TransactionPriority, TransactionValidity, TransactionValidityError, ValidTransaction,
 	},
-	FixedPointNumber, FixedPointOperand, FixedU128, Perbill, Perquintill, RuntimeDebug,
+	FixedPointNumber, FixedU128, Perbill, Perquintill, RuntimeDebug,
 };
 use sp_std::prelude::*;
 pub use types::{FeeDetails, InclusionFee, RuntimeDispatchInfo};
@@ -461,10 +461,7 @@ pub mod pallet {
 	}
 }
 
-impl<T: Config> Pallet<T>
-where
-	BalanceOf<T>: FixedPointOperand,
-{
+impl<T: Config> Pallet<T> {
 	/// Query the data that we know about the fee of a given `call`.
 	///
 	/// This pallet is not and cannot be aware of the internals of a signed extension, for example
@@ -649,7 +646,6 @@ where
 impl<T> Convert<Weight, BalanceOf<T>> for Pallet<T>
 where
 	T: Config,
-	BalanceOf<T>: FixedPointOperand,
 {
 	/// Compute the fee for the specified weight.
 	///
@@ -678,7 +674,7 @@ pub struct ChargeTransactionPayment<T: Config>(#[codec(compact)] BalanceOf<T>);
 impl<T: Config> ChargeTransactionPayment<T>
 where
 	T::RuntimeCall: Dispatchable<Info = DispatchInfo, PostInfo = PostDispatchInfo>,
-	BalanceOf<T>: Send + Sync + FixedPointOperand,
+	BalanceOf<T>: Send + Sync,
 {
 	/// utility constructor. Used only in client/factory code.
 	pub fn from(fee: BalanceOf<T>) -> Self {
@@ -800,7 +796,7 @@ impl<T: Config> sp_std::fmt::Debug for ChargeTransactionPayment<T> {
 
 impl<T: Config> SignedExtension for ChargeTransactionPayment<T>
 where
-	BalanceOf<T>: Send + Sync + From<u64> + FixedPointOperand,
+	BalanceOf<T>: Send + Sync + From<u64>,
 	T::RuntimeCall: Dispatchable<Info = DispatchInfo, PostInfo = PostDispatchInfo>,
 {
 	const IDENTIFIER: &'static str = "ChargeTransactionPayment";
@@ -866,7 +862,6 @@ where
 impl<T: Config, AnyCall: GetDispatchInfo + Encode> EstimateCallFee<AnyCall, BalanceOf<T>>
 	for Pallet<T>
 where
-	BalanceOf<T>: FixedPointOperand,
 	T::RuntimeCall: Dispatchable<Info = DispatchInfo, PostInfo = PostDispatchInfo>,
 {
 	fn estimate_call_fee(call: &AnyCall, post_info: PostDispatchInfo) -> BalanceOf<T> {

substrate/primitives/arithmetic/src/fixed_point.rs

@@ -52,16 +52,18 @@ pub trait FixedPointOperand:
 {
 }
 
-impl FixedPointOperand for i128 {}
-impl FixedPointOperand for u128 {}
-impl FixedPointOperand for i64 {}
-impl FixedPointOperand for u64 {}
-impl FixedPointOperand for i32 {}
-impl FixedPointOperand for u32 {}
-impl FixedPointOperand for i16 {}
-impl FixedPointOperand for u16 {}
-impl FixedPointOperand for i8 {}
-impl FixedPointOperand for u8 {}
+impl<T> FixedPointOperand for T where
+	T: Copy
+		+ Clone
+		+ Bounded
+		+ Zero
+		+ Saturating
+		+ PartialOrd
+		+ UniqueSaturatedInto<u128>
+		+ TryFrom<u128>
+		+ CheckedNeg
+{
+}
 
 /// Something that implements a decimal fixed point number.
 ///

substrate/primitives/arithmetic/src/traits.rs

@@ -59,6 +59,7 @@ pub trait BaseArithmetic:
 	+ CheckedMul
 	+ CheckedDiv
 	+ CheckedRem
+	+ CheckedNeg
 	+ Ensure
 	+ Saturating
 	+ PartialOrd<Self>
@@ -116,6 +117,7 @@ impl<
 			+ CheckedMul
 			+ CheckedDiv
 			+ CheckedRem
+			+ CheckedNeg
 			+ Ensure
 			+ Saturating
 			+ PartialOrd<Self>