feature: impl evm_reducible_balance

frame/balances/src/impl_fungible.rs

@@ -68,13 +68,31 @@ impl<T: Config<I>, I: 'static> fungible::Inspect<T::AccountId> for Pallet<T, I>
 		// Liquid balance is what is neither on hold nor frozen/required for provider.
 		a.free.saturating_sub(untouchable)
 	}
-
+	/// This method will only be used until migrations to fungible traits are done.
 	fn evm_reducible_balance(
 		who: &T::AccountId,
 		preservation: Preservation,
 		force: Fortitude,
 	) -> Self::Balance {
-		Self::account(who).usable()
+		let a = Self::account(who);
+		let mut untouchable = Zero::zero();
+		if force == Polite {
+			// In the case for EVM, we only care about frozen balance.
+			untouchable = a.frozen;
+		}
+		// If we want to keep our provider ref..
+		if preservation == Preserve
+			// ..or we don't want the account to die and our provider ref is needed for it to live..
+			|| preservation == Protect && !a.free.is_zero() &&
+				frame_system::Pallet::<T>::providers(who) == 1
+			// ..or we don't care about the account dying but our provider ref is required..
+			|| preservation == Expendable && !a.free.is_zero() &&
+				!frame_system::Pallet::<T>::can_dec_provider(who)
+		{
+			// ..then the ED needed..
+			untouchable = untouchable.max(T::ExistentialDeposit::get());
+		}
+		a.free.saturating_sub(untouchable)
 	}
 	fn can_deposit(
 		who: &T::AccountId,