Github user danielsun1106 commented on the pull request:
https://github.com/apache/groovy/commit/f88d0122525cabf6bdf61ab051533f9983f352f1#commitcomment-28390941
In src/test/groovy/SerializableCompatibilityTest.groovy:
In src/test/groovy/SerializableCompatibilityTest.groovy on line 40:
Yep, as its name shows, it is generated by 2.4---
