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type[Self] converted to a callable drops constructor signature #5591
Description
Describe the Bug
from typing import Callable
def identity[**P, R](cb: Callable[P, R]) -> Callable[P, R]:
return cb
class Foo:
def __init__(self, value: int) -> None: ...
@classmethod
def meth(cls) -> None:
reveal_type(cls) # type[Self@Foo]
reveal_type(identity(cls)) # (*args: Any, **kwds: Any) -> Any
cls("") # error, expected
f: Callable[[str], Foo] = cls # no error
def explicit(t: type[Foo]) -> None:
reveal_type(identity(t)) # (value: int) -> FooWhen a variable declared type[Self] (such as the cls parameter of a classmethod) is used where a callable is expected, pyrefly treats it as type.__call__ instead of using the constructor of the class bound to Self.
Sandbox Link
(Only applicable for extension issues) IDE Information
No response
Activity
crypt0lith commentedon Nov 9, 2026
#claim
The fix would be adding a new arm for
SelfTypeafter the existing one:pyrefly/pyrefly/lib/solver/subset.rs
Lines 2594 to 2596 in 7431fb0
github-actions commentedon Nov 9, 2026
@crypt0lith you've claimed this issue — it's now assigned to you. Thanks for picking it up! 🎉
shahhamdihassan commentedon Nov 9, 2026
Thanks for the report, this reproduces on the latest release and on main: sandbox
@crypt0lith thanks for picking it up!
Convert type[Self] to callable from class constructor
Convert type[Self] to callable from class constructor (meta#5592)