Bare `Tuple` should mean `Tuple[Any, ...]`. #2185

gvanrossum · 2016-09-26T18:59:33Z

Fix #2184. (See also python/typing#284.)

JukkaL · 2016-09-26T19:00:46Z

test-data/unit/check-tuples.test

+def f(a: Tuple) -> None: pass
+f(())
+f((1,))
+f(('', ''))


Call with a non-tuple argument such as an int.

gvanrossum · 2016-09-26T20:01:20Z

Ouch. I just realized that I broke the behavior of Tuple[()]. I added a test for that but didn't finish that thought.

gvanrossum · 2016-09-26T22:42:28Z

@JukkaL Another look? I added the test with int you requested, and fixed the issue I introduced with Tuple[()] -- that was a little awkward since the information about whet 8000 her the original code was Tuple or Tuple[()] was lost by the time it reached typeanal.py.

I also looked into the difference with the next block and decided to leave that alone (although reducing it to self.builtin_type('builtins.tuple', [t.args[0].accept(self)]) made all tests pass, I decided to give it the benefit of the doubt, maybe the line number is important after all).

elazarg · 2016-09-27T01:18:58Z

If I understand correctly, this flag may be useful in order to write Union[] as a synonym for UninhabitedType (i.e. NoReturn) , while still allowing Union to be Union[Any] (which is actually Any).

gvanrossum · 2016-09-27T01:51:14Z

Sorry, Union[](like Tuple[]) is invalid syntax. We use Tuple[()] as an
escape, but Union[()] would be too ugly for such a purpose.

JukkaL · 2016-09-27T13:18:45Z

test-data/unit/check-tuples.test

+from typing import Tuple
+def f(a: Tuple[()]) -> None: pass
+f(())
+f((1,))  # E: Argument 1 to "f" has incompatible type "Tuple[int]"; expected "Tuple[]"


Maybe update the output 8000 of an empty tuple to be Tuple[()] instead of Tuple[]?

JukkaL · 2016-09-27T13:20:33Z

Other than the comment above, this looks good to me.

gvanrossum · 2016-09-27T15:31:24Z

About Tuple[] vs. Tuple[()] in output... I have the patch for that ready,
but I'm not sure I like it. I had to change some other tests that had
Tuple[] in their output, and somehow I have a feeling that for a user,
seeing Tuple[] is more indicative of "the type of an empty tuple" than
Tuple[()], which only works for obscure reasons. So I think I'd like to
leave this for a later time.

JukkaL · 2016-09-27T16:04:02Z

OK, sounds reasonable Tuple[()] really isn't the most intuitive thing ever.

Fix #2184. Bare Tuple should mean Tuple[Any, ...].

0ce9e69

JukkaL reviewed Sep 26, 2016

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Guido van Rossum added 2 commits September 26, 2016 14:46

Fix things so Tuple and Tuple[()] are distinguishable.

229edb8

Even simpler

181cc3f

JukkaL reviewed Sep 27, 2016

View reviewed changes

gvanrossum merged commit 0d2c594 into master Sep 27, 2016

gvanrossum deleted the bareTuple branch September 27, 2016 17:03

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Bare `Tuple` should mean `Tuple[Any, ...]`. #2185

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Bare Tuple should mean Tuple[Any, ...]. #2185

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Bare `Tuple` should mean `Tuple[Any, ...]`. #2185

Bare `Tuple` should mean `Tuple[Any, ...]`. #2185