__class__ seen as type[Self] vs runtime #10685
Description
Describe the bug
__class__ within a method's body resolves to the concrete class that method has been created in, and doesn't consider subclasses.
Pyright seems to incorrectly treat that identifier as type[Self], while it really should be type[<class name>] (and thus not assignable to type[Self]). I think the following bug(s) stem from this.
Prior to Pyright 1.1.401, the code in #10451 rightly reported an error at this return statement:
return __class__() # Type "Self@Foo" is not assignable to return type "Self@Foo"In >=1.1.401, this diagnostic went away, likely due to the fix for the linked issue.
Code or Screenshots
Prior to the fix:
from typing import Self, reveal_type
class Foo:
def func(self) -> Self:
reveal_type(__class__) # type[Self@Foo]
reveal_type(__class__()) # Self@Foo
_: Self = __class__() # ok
return __class__() # Type "Self@Foo" is not assignable to return type "Self@Foo"After the fix:
class Foo:
def func(self) -> Self:
reveal_type(__class__) # type[Self@Foo]; should probably be "type[Foo]"
reveal_type(__class__()) # Self@Foo; should probably be "Foo"
_: Self = __class__() # ok; should be an error
return __class__() # ok; should be an errorclass Bar(Foo): ...
bar = Bar()
reveal_type(bar.func()) # pylance: Type of "bar.func()" is "Bar"; runtime: Runtime type is 'Foo'VS Code extension or command-line
Pylance; the (somewhat correct) error message is present in 2025.5.100.
In 2025.5.101, it went away.