add event deposit for eventual eviction upon pay_rent

frame/contracts/src/exec.rs

@@ -356,7 +356,15 @@ where
 		// Assumption: pay_rent doesn't collide with overlay because
 		// pay_rent will be done on first call and dest contract and balance
 		// cannot be changed before the first call
-		let contract_info = rent::pay_rent::<T>(&dest);
+		let (rent_outcome, contract_info) = rent::pay_rent::<T>(&dest);
+
+		// Deposit an event to indicate contract eviction.
+		if rent_outcome == rent::RentOutcome::Evicted {
+			self.deferred.push(DeferredAction::DepositEvent {
+				event: RawEvent::Evicted(dest.clone()),
+				topics: Vec::new(),
+			});
+		}
 
 		// Calls to dead contracts always fail.
 		if let Some(ContractInfo::Tombstone(_)) = contract_info {

frame/contracts/src/rent.rs

@@ -181,8 +181,8 @@ fn try_evict_or_and_pay_rent<T: Trait>(
 /// Make account paying the rent for the current block number
 ///
 /// NOTE: This function acts eagerly.
-pub fn pay_rent<T: Trait>(account: &T::AccountId) -> Option<ContractInfo<T>> {
-	try_evict_or_and_pay_rent::<T>(account, Zero::zero(), true).1
+pub fn pay_rent<T: Trait>(account: &T::AccountId) -> (RentOutcome, Option<ContractInfo<T>>) {
+	try_evict_or_and_pay_rent::<T>(account, Zero::zero(), true)
 }
 
 /// Evict the account if it should be evicted at the given block number.