builtins stubtest exceptions

[hatal175]

• I've just left 'class function' - anyone can explain what it is and why it is there?

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

pip (https://github.com/pypa/pip.git)
+ src/pip/_internal/operations/install/wheel.py:620: error: Incompatible types in assignment (expression has type "chain[File]", variable has type "map[File]")
+ src/pip/_internal/operations/install/wheel.py:646: error: Incompatible types in assignment (expression has type "filterfalse[File]", variable has type "map[File]")
+ src/pip/_internal/operations/install/wheel.py:650: error: Incompatible types in assignment (expression has type "chain[File]", variable has type "map[File]")


bidict (https://github.com/jab/bidict.git)
+ bidict/_orderedbidict.py:63: error: "object" not callable

[hauntsaninja]

There's #2999 for builtins.function

[JelleZijlstra]

The bidictfailure is a bit nasty: it's on a line key = next((reversed if last else iter)(self)). This doesn't work any more because now mypy infers object for reversed if last else iter. Still, this sort of issue seems rare so I'm OK with moving forward with these changes.

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

pip (https://github.com/pypa/pip.git)
+ src/pip/_internal/operations/install/wheel.py:620: error: Incompatible types in assignment (expression has type "chain[File]", variable has type "map[File]")
+ src/pip/_internal/operations/install/wheel.py:646: error: Incompatible types in assignment (expression has type "filterfalse[File]", variable has type "map[File]")
+ src/pip/_internal/operations/install/wheel.py:650: error: Incompatible types in assignment (expression has type "chain[File]", variable has type "map[File]")


bidict (https://github.com/jab/bidict.git)
+ bidict/_orderedbidict.py:63: error: "object" not callable

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

pip (https://github.com/pypa/pip.git)
+ src/pip/_internal/operations/install/wheel.py:620: error: Incompatible types in assignment (expression has type "chain[File]", variable has type "map[File]")
+ src/pip/_internal/operations/install/wheel.py:646: error: Incompatible types in assignment (expression has type "filterfalse[File]", variable has type "map[File]")
+ src/pip/_internal/operations/install/wheel.py:650: error: Incompatible types in assignment (expression has type "chain[File]", variable has type "map[File]")


bidict (https://github.com/jab/bidict.git)
+ bidict/_orderedbidict.py:63: error: "object" not callable

[JelleZijlstra]

I wonder if these were added on purpose to make bytes fulfill the SupportsInt and SupportsFloat protocols. int(b'12') works at runtime. Probably safer to keep them.

[hatal175]

1. no mypy primer diffs
2. the int __new__ function specifically gets bytes (so does float) and treats it as a string: https://github.com/python/cpython/blob/62ec63864822de1dd1933225584e8503ac40c1f9/Objects/longobject.c#L4960
3. Other functions that receive SupportsInt fail on bytes - itertools.count(b'1',1)

[JelleZijlstra]

Sounds good, I will merge

[ktbarrett]

Why were all these overloaded functions changed to classes? This breaks deduction in certain contexts.

[Akuli]

I'm not yet convinced that this PR has anything to do with that. I added this function to your mypy playground link, based on what this PR deletes, and used it instead of zip:

def myzip(__iter1: Iterable[_T1], __iter2: Iterable[_T2]) -> Iterator[Tuple[_T1, _T2]]:
    return zip(__iter1, __iter2)

It still gives the same number of errors.