Regression for typing.Annotated when aliased

[fellhorn]

Describe the bug

Pyright 1.1.379 seems to have introduced a different behavior for typing.Annotated type forms when:

• enableExperimentalFeatures: true is set
• typing.Annotated is aliased in another module

I assume this is due to the provisional support for draft PEP 747 and the TypeForm special form.

We discovered this because it breaks jaxtyping type annotations, which internally aliases typing.Annotated.

Code or Screenshots

The file to type check:

from typing import Annotated

# These two alias typing.Annotated
from .indirection import IndirectAnnotated
from jaxtyping import Int32


def test(
    inp1: Annotated[int, "metadata"],  # This is valid
    inp2: IndirectAnnotated[int, "metadata"], # "metadata" is not defined (reportUndefinedVariable)
    inp3: Int32[int, "metadata"], # "metadata" is not defined (reportUndefinedVariable)
):
    pass

indirection.py

from typing import (
    Annotated as IndirectAnnotated,
)

__all__ = [
    "IndirectAnnotated",
]

pyrightconfig.json

{
    "include": [
        "./*",
    ],
    "enableExperimentalFeatures": true,
}

If your code relies on symbols that are imported from a third-party library, include the associated import statements and specify which versions of those libraries you have installed.

indirection.py provides a minimal example for jaxtyping's internal logic.

VS Code extension or command-line

All pyright versions >=1.1.379 as well as pylance v2024.9.101 (pre release) produce the issue:

> pyright -p pyrightconfig.json 
/workspaces/pyright_test/test.py
  /workspaces/pyright_test/test.py:11:35 - error: "metadata" is not defined (reportUndefinedVariable)
  /workspaces/pyright_test/test.py:12:22 - error: "metadata" is not defined (reportUndefinedVariable)
2 errors, 0 warnings, 0 informations 

[fellhorn]

I found a smaller example to reproduce the issue in the pyright playground:

Code sample in pyright playground

from typing import Annotated

IndirectAnnotated = Annotated

def test(
    inp1: Annotated[int, "metadata"],  # This is valid
    inp2: IndirectAnnotated[int, "metadata"], # "metadata" is not defined (reportUndefinedVariable)
):
    pass

[erictraut]

Thanks for helping shake out the bugs in the provisional implementation of TypeForm.

This will be addressed in the next release.

[fellhorn]

Thanks a lot, Eric! It's always amazing to see how quickly you react to bug reports here in pyright.

[erictraut]

This is addressed in pyright 1.1.383.