Re: from __future__ import annotations bug?

2023-06-30 Thread Joseph Garvin via Python-list 
Should mention this also affects Protocol[Buzz]

On Fri, Jun 30, 2023, 5:35 PM Joseph Garvin  wrote:

> ```
> from __future__ import annotations
> from typing import Generic, TypeVar
>
> T = TypeVar("T")
> class Foo(Generic[T]): ...
> class Bar(Foo[Buzz]): ... # NameError here
> class Buzz: ...
> ```
>
> This will error, despite the __future__ import, because cpython is trying
> to look up Buzz before it's defined, even though we have supposedly
> prevented annotations from being processed. I realize that Class[Args] is
> allowed in that area in general and isn't always type annotation related,
> but does this mean that even with PEP 649 that forward references will
> still be needed?
>
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from __future__ import annotations bug?

2023-06-30 Thread Joseph Garvin via Python-list 
```
from __future__ import annotations
from typing import Generic, TypeVar

T = TypeVar("T")
class Foo(Generic[T]): ...
class Bar(Foo[Buzz]): ... # NameError here
class Buzz: ...
```

This will error, despite the __future__ import, because cpython is trying
to look up Buzz before it's defined, even though we have supposedly
prevented annotations from being processed. I realize that Class[Args] is
allowed in that area in general and isn't always type annotation related,
but does this mean that even with PEP 649 that forward references will
still be needed?
-- 
https://mail.python.org/mailman/listinfo/python-list