Type error in Pylance

[denisrosset]

This is with Pylance language server 2022.5.1 (pyright e0e07d31), Python 3.10 and hypothesis 6.46.5

Edit: the analysis mode is strict:

    "python.analysis.typeCheckingMode": "strict",

The following snippet:

from typing import Tuple

import hypothesis.strategies as st

def my_hyp() -> st.SearchStrategy[Tuple[int, int]]:
    return st.tuples(st.integers(0, 10), st.integers(0, 10))

fails to typecheck with:

Type of "tuples" is partially unknown
  Type of "tuples" is "Overload[() -> SearchStrategy[Tuple[()]], (a1: SearchStrategy[Ex@tuples]) -> SearchStrategy[Tuple[Ex@tuples]], (a1: SearchStrategy[Ex@tuples], a2: SearchStrategy[T@tuples]) -> SearchStrategy[Tuple[Ex@tuples, T@tuples]], (a1: SearchStrategy[Ex@tuples], a2: SearchStrategy[T@tuples], a3: SearchStrategy[T3@tuples]) -> SearchStrategy[Tuple[Ex@tuples, T@tuples, T3@tuples]], (a1: SearchStrategy[Ex@tuples], a2: SearchStrategy[T@tuples], a3: SearchStrategy[T3@tuples], a4: SearchStrategy[T4@tuples]) -> SearchStrategy[Tuple[Ex@tuples, T@tuples, T3@tuples, T4@tuples]], (a1: SearchStrategy[Ex@tuples], a2: SearchStrategy[T@tuples], a3: SearchStrategy[T3@tuples], a4: SearchStrategy[T4@tuples], a5: SearchStrategy[T5@tuples]) -> SearchStrategy[Tuple[Ex@tuples, T@tuples, T3@tuples, T4@tuples, T5@tuples]], (*args: SearchStrategy[Any]) -> SearchStrategy[Tuple[Unknown, ...]], (*args: Unknown) -> TupleStrategy]"

I'd be happy to push this myself to the pylance issues if I'm advised to!

[Zac-HD]

Ah, it might want us to prefix the pos-only argnames with an underscore? Or it might be some other issue that we can solve locally. Thanks for the report!

[denisrosset]

If I had to guess, it's because of the Tuple without arguments in the "real" declaration. I've got the same error message in numpy.

I think this should be pushed to Pylance/Pyright:
https://github.com/microsoft/pylance-release/issues

I've edited the issue to precise that the analysis mode is strict.

[Zac-HD]

Ah, if you've got the same error from Numpy then it probably does make sense to treat it as a pyright issue, since I'm pretty sure it's pyright rather than pylance. Do you want to open that upstream, and tag me?

[rsokl]

I don't think that there is a problem with pyright here. This is fixed by updating both lines 110 and 116 in collections.py to:

def tuples(*args: SearchStrategy[Any]) -> SearchStrategy[Tuple[Any, ...]]:  # noqa: F811

[denisrosset]

@rsokl Cool! so Any is the magic escape valve for such issues?

[rsokl]

Specifying Tuple is indeed a partially unknown annotation. pyright-strict wants you to tell it "I explicitly mean that it is a tuple of arbitrary length and contents", which is spelled by Tuple[Any, ...].

Similarly, e.g., Dict would be partially unknown until you specify Dict[Any, Any]

And, for some reason, pyright-strict expects that the actual implementation (line 116) to also include annotations, even though this seems to be redundant with the lowest overload. I haven't taken the time to see if mypy wants the same.

@Zac-HD I can try to fix this sometime today. Would you also like me to make the overloads use pos-only args (a1 -> __a1)?

[Zac-HD]

Thanks! Yeah, let's also use pos-only args - they are in fact positional-only, so.

[rsokl]

For the record, the same issue occurs in one_of. I am doing a general tune up in #3349