Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/5940#discussion_r186022377
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/codegen/AggregationCodeGenerator.scala
---
@@ -641,7 +641,8 @@ class AggregationCodeGenerator(
| java.util.Map.Entry entry = (java.util.Map.Entry)
mergeIt$i.next();
| Object k = entry.getKey();
--- End diff --
Change this line to `${classOf[Row].getCanonicalName} k =
(${classOf[Row].getCanonicalName}) entry.getKey();`
---