Merge branch 'dev' into feature/inline-tx-id

Author: chopin-fan

src/AElf.WebApp.Application.Chain/Services/TransactionResultAppService.cs

@@ -119,8 +119,16 @@ await _transactionResultProxyService.InvalidTransactionResultService.GetInvalidT
             }
         }
 
+        var chain = await _blockchainService.GetChainAsync();
+        if (chain.BestChainHeight - output.Transaction.RefBlockNumber > KernelConstants.ReferenceBlockValidPeriod 
+            && transactionResult.Status == TransactionResultStatus.NotExisted)
+        {
+            // set a the Error message to the output to infer that the transaction will never succeed.
+            var error = "The transaction is already expired, and it will never succeed.";
+            output.Error = TransactionErrorResolver.TakeErrorMessage(error, _webAppOptions.IsDebugMode);
+            return output;
+        }
         return output;
-        
     }
 
     /// <summary>