Following script fails with trunk(0.17).
a = load 'test.txt' as (mytuple:tuple (), gpa:float);
b = foreach a generate mytuple as (mytuple2:(name:int, age:double));
store b into '/tmp/deleteme';
2017-05-16 09:52:31,280 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 2999: Unexpected internal error. null
(This is a continuation from the as-clause fix at PIG-2315 and follow up jira PIG-4933)