The first argument to Iterator.zip is either an iterable of iterators or an object whose values are expected to be iterators.
In the former case, fillers (if passed) should be expected to be an iterable of values. Right now step 13.g.ii.1 uses GetIteratorFlattenable, which is for iterator-or-iterables, not iterables. There's no reason to support bare iterators here. It should match the first argument in being an iterable.
The first argument to
Iterator.zipis either an iterable of iterators or an object whose values are expected to be iterators.In the former case,
fillers(if passed) should be expected to be an iterable of values. Right now step 13.g.ii.1 usesGetIteratorFlattenable, which is for iterator-or-iterables, not iterables. There's no reason to support bare iterators here. It should match the first argument in being an iterable.