next(foo) should be converted to iter(foo).next() rather than foo.next()

[Denis Zawada]

If foo already defines method called next() (In Python 3 iter.next() has been renamed to iter.__next__(), so it’s a valid name), calling foo.next() will call that method rather than iter(foo).next() as is intended. For example:

class Foo:
  def next(self):
    return 'bar'
  def __iter__(self):
    return iter(['abc'])

assert next(Foo()) == 'abc'

Will get converted to:

assert Foo().next() == 'abc'

Whereas should get converted:

assert iter(Foo()).next() == 'abc'

There are no potential regressions by changing foo.next() to iter(foo).next(), since iter() is called first by next() in Python 3 anyway.

[Denis Zawada (ohdeno)]

Actually this is totally wrong…