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/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>>,