mypy doesn't escape typevars from generics in self-type #18400
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A5rocks
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Turns out this applies to TypeVars too -- I'll update this issue for that (since it's simpler). |
A5rocks
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A5rocks
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A5rocks
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A5rocks
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Hm. Are you sure this is supposed to work at all? There is no precedent of bare typevar at top level working like this, otherwise we'd have some fancy features like As a rule of thumb, there's no way to spell your repro using If I fix your example to put the typevar in scope, from typing import Generic, TypeVar, Callable
T = TypeVar("T")
V = TypeVar("V")
class X(Generic[T]):
def f(self: X[Callable[[V], None]]) -> Callable[[V], V]:
def inner_f(v: V) -> V:
return v
return inner_f
def fn(_: T) -> None:
reveal_type(X[Callable[[T], None]]().f()) # N: Revealed type is "def (T`-1) -> T`-1" |
This should be valid because callables capture their generic. I'm also just doing this for a more simple reproducer. Here's the less minimized version of my failing example: from __future__ import annotations
from dataclasses import dataclass
from typing import TypeVarTuple, Unpack, Generic, TypeVar, Any, overload
from collections.abc import Callable
# TODO: hide this in an internal file so that I can have descriptive names without polluting namespace
Args = TypeVarTuple("Args")
class Build(Generic[Unpack[Args]]):
pass
class Built(Generic[Unpack[Args]]):
pass
From = TypeVarTuple("From")
To = TypeVarTuple("To")
InitialCallable = TypeVar("InitialCallable", bound=Callable[[Build[Unpack[tuple[Any, ...]]]], Build[Unpack[tuple[Any, ...]]]])
@dataclass
class Builder(Generic[InitialCallable]):
initial_callable: InitialCallable
def __call__(self: Builder[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]]) -> Callable[[Callable[[object, Unpack[To]], None]], Built[Unpack[From]]]:
def build_up(in_progress: Callable[[object, Unpack[To]], None]) -> Built[Unpack[From]]:
...
return build_up
def make_builder() -> Callable[[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]], Builder[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]]]:
def inner_make_builder(command: Callable[[Build[Unpack[From]]], Build[Unpack[To]]]) -> Builder[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]]:
return Builder(command)
return inner_make_builder
from typing import Unpack, TypeVarTuple
#Args = TypeVarTuple("Args")
def test_basic_command() -> None:
@make_builder()
def command_builder(b: Build[Unpack[Args]]) -> Build[Unpack[Args]]:
return b
reveal_type(command_builder()) # N: Revealed type is "def (def (builtins.object, *Never)) -> __main__.Built[Unpack[builtins.tuple[Never, ...]]]"
# ^ I expect this to workTo prove this should work, I've turned from __future__ import annotations
from dataclasses import dataclass
from typing import TypeVarTuple, Unpack, Generic, TypeVar, Any, overload
from collections.abc import Callable
# TODO: hide this in an internal file so that I can have descriptive names without polluting namespace
Args = TypeVarTuple("Args")
class Build(Generic[Unpack[Args]]):
pass
class Built(Generic[Unpack[Args]]):
pass
From = TypeVarTuple("From")
To = TypeVarTuple("To")
InitialCallable = TypeVar("InitialCallable", bound=Callable[[Build[Unpack[tuple[Any, ...]]]], Build[Unpack[tuple[Any, ...]]]])
@dataclass
class Builder(Generic[InitialCallable]):
initial_callable: InitialCallable
def Builder_call(self: Builder[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]]) -> Callable[[Callable[[object, Unpack[To]], None]], Built[Unpack[From]]]:
def build_up(in_progress: Callable[[object, Unpack[To]], None]) -> Built[Unpack[From]]:
...
return build_up
def make_builder() -> Callable[[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]], Builder[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]]]:
def inner_make_builder(command: Callable[[Build[Unpack[From]]], Build[Unpack[To]]]) -> Builder[Callable[[Build[Unpack[From]]], Build[Unpack[To]]]]:
return Builder(command)
return inner_make_builder
from typing import Unpack, TypeVarTuple
#Args = TypeVarTuple("Args")
def test_basic_command() -> None:
@make_builder()
def command_builder(b: Build[Unpack[Args]]) -> Build[Unpack[Args]]:
return b
reveal_type(Builder_call(command_builder)) # N: Revealed type is "def [From] (def (builtins.object, *Unpack[From`330])) -> __main__.Built[Unpack[From`330]]"
# ^ now it works! |
Bug Report
Passing a callable to another which matches the typevar with another typevar doesn't allow passing them into the return type. (if that makes no sense, the reproducer below is simple)
To Reproduce
Expected Behavior
I don't expect a
Never.Your Environment
Checked on mypy playground.
--strictmypy.ini(and other config files): N/AThe text was updated successfully, but these errors were encountered: