Skip to content

Use type variable bound to infer constraints #12230

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Feb 22, 2022
+25 −0
Merged

Use type variable bound to infer constraints #12230

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
9888686
Use type variable bound to infer constraints
JukkaL Feb 21, 2022
341da97
Merge branch 'master' into mypy-regression-2
JukkaL Feb 22, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions mypy/constraints.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -513,6 +513,10 @@ def visit_instance(self, template: Instance) -> List[Constraint]:
return infer_constraints(template,
mypy.typeops.tuple_fallback(actual),
self.direction)
elif isinstance(actual, TypeVarType):
if not actual.values:
return infer_constraints(template, actual.upper_bound, self.direction)
return []
else:
return []

Expand Down
21 changes: 21 additions & 0 deletions test-data/unit/check-protocols.test
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2807,6 +2807,27 @@ class MyClass:
[builtins fixtures/isinstance.pyi]
[typing fixtures/typing-full.pyi]

[case testProtocolAndTypeVariableSpecialCase]
from typing import TypeVar, Iterable, Optional, Callable, Protocol

T_co = TypeVar('T_co', covariant=True)

class SupportsNext(Protocol[T_co]):
def __next__(self) -> T_co: ...

N = TypeVar("N", bound=SupportsNext, covariant=True)

class SupportsIter(Protocol[T_co]):
def __iter__(self) -> T_co: ...

def f(i: SupportsIter[N]) -> N: ...

I = TypeVar('I', bound=Iterable)

def g(x: I, y: Iterable) -> None:
f(x)
f(y)

[case testMatchProtocolAgainstOverloadWithAmbiguity]
from typing import TypeVar, Protocol, Union, Generic, overload

Expand Down