AttributeError in new for loop checking

[dopplershift]

I'm getting this error now that I updated to 1.1.0:

Traceback (most recent call last):
  File "/Users/rmay/miniconda3/envs/py36/lib/python3.6/multiprocessing/pool.py", line 119, in worker
    result = (True, func(*args, **kwds))
  File "/Users/rmay/miniconda3/envs/py36/lib/python3.6/site-packages/flake8/checker.py", line 648, in _run_checks
    return checker.run_checks()
  File "/Users/rmay/miniconda3/envs/py36/lib/python3.6/site-packages/flake8/checker.py", line 579, in run_checks
    self.run_ast_checks()
  File "/Users/rmay/miniconda3/envs/py36/lib/python3.6/site-packages/flake8/checker.py", line 493, in run_ast_checks
    for (line_number, offset, text, check) in runner:
  File "/Users/rmay/miniconda3/envs/py36/lib/python3.6/site-packages/flake8_builtins.py", line 73, in run
    for line, offset, msg, rtype in value:
  File "/Users/rmay/miniconda3/envs/py36/lib/python3.6/site-packages/flake8_builtins.py", line 129, in check_for_loop
    if name.id in BUILTINS:
AttributeError: 'Tuple' object has no attribute 'id'

I'm seeing this on Windows, Linux, and Mac on 2.7, 3.5, 3.6. This example code (which pulls a tuple out during iteration) is enough to trigger the error (and removing that line makes the error go away):

a = [('a', 'b'), ('c', 'd')]
for i, (x, y) in enumerate(a):
    print(i, x, y)

[gforcada]

@dopplershift thanks, I was not expecting this one :-) I will try to fix it as soon as I can, pull requests are welcome, of course.

[dhood]

We are also getting this after updating to 1.1.0, same traceback (https://ci.ros2.org/view/nightly/job/nightly_linux-aarch64_debug/396/testReport/junit/(root)/rosidl_parser/flake8_xunit_missing_result//)

[dhood]

For reference, the code being checked that caused our error is here (both subdirectories are checked) and I noticed that there is at least one instance of a tuple in the for loop at https://github.com/ros2/rosidl/blob/774a3cd4509f2d432b7325f60434765a9ccd5cee/rosidl_parser/test/test_parse_primitive_value_string.py#L63

[dopplershift]

Fix (with test) in #20 .