Add arithmetic dispatch errors. (#8726)

* Add arithmetic dispatch errors.

* Replace custom overflow errors.

* Replace custom underflow and division by zero errors.

* Replace overflow/underflow in token error.

* Add token and arithmetic errors in dispatch error equality test.

* Trigger CI.

substrate/frame/recovery/src/lib.rs

@@ -154,7 +154,7 @@
 use sp_std::prelude::*;
 use sp_runtime::{
 	traits::{Dispatchable, SaturatedConversion, CheckedAdd, CheckedMul},
-	DispatchResult
+	DispatchResult, ArithmeticError,
 };
 use codec::{Encode, Decode};
 
@@ -313,8 +313,6 @@ decl_error! {
 		Threshold,
 		/// There are still active recovery attempts that need to be closed
 		StillActive,
-		/// There was an overflow in a calculation
-		Overflow,
 		/// This account is already set up for recovery
 		AlreadyProxy,
 		/// Some internal state is broken.
@@ -443,10 +441,10 @@ decl_module! {
 			// Total deposit is base fee + number of friends * factor fee
 			let friend_deposit = T::FriendDepositFactor::get()
 				.checked_mul(&friends.len().saturated_into())
-				.ok_or(Error::<T>::Overflow)?;
+				.ok_or(ArithmeticError::Overflow)?;
 			let total_deposit = T::ConfigDepositBase::get()
 				.checked_add(&friend_deposit)
-				.ok_or(Error::<T>::Overflow)?;
+				.ok_or(ArithmeticError::Overflow)?;
 			// Reserve the deposit
 			T::Currency::reserve(&who, total_deposit)?;
 			// Create the recovery configuration
@@ -581,7 +579,7 @@ decl_module! {
 			let current_block_number = <system::Pallet<T>>::block_number();
 			let recoverable_block_number = active_recovery.created
 				.checked_add(&recovery_config.delay_period)
-				.ok_or(Error::<T>::Overflow)?;
+				.ok_or(ArithmeticError::Overflow)?;
 			ensure!(recoverable_block_number <= current_block_number, Error::<T>::DelayPeriod);
 			// Make sure the threshold is met
 			ensure!(