`name-defined` is whitespace-dependent

[injust]

Bug Report

In an attrs class with a field that is named the same as an import, the name-defined check is whitespace-dependent.

To Reproduce

import httpx
from attrs import define, field


@define
class Foo:
    httpx: httpx.AsyncClient = field(
        factory=lambda: httpx.AsyncClient()
    )

Expected Behavior

This code should type check identically to:

import httpx
from attrs import define, field


@define
class Foo:
    httpx: httpx.AsyncClient = field(factory=lambda: httpx.AsyncClient())  # on one line

Actual Behavior

test.py:7: error: Name "httpx.AsyncClient" is not defined  [name-defined]

Your Environment

• Mypy version used: 1.17.1
• Python version used: 3.13.6
• attrs version used: 25.3.0

[sterliakov]

Attrs is a red herring here.

MRE:

# foo.py
class Bar:
    pass

# demo.py
import foo

def nop(fn: object) -> foo.Bar:
    return foo.Bar()

class Fail:
    foo: foo.Bar = nop(
        lambda: 0
    )

class Ok:
    foo: foo.Bar = nop(lambda: 0)

$ mypy demo.py
demo.py:7: error: Name "foo.Bar" is not defined  [name-defined]
Found 1 error in 1 file (checked 1 source file)

Note that the lambda is important (so an extra deferral pass has to do something with this), replacing it with just 0 eliminates the diagnostic. Also note that this only works when the file has from __future__ import annotations (otherwise this will be a runtime error, if my in-brain interpreter is not yet dead today), but mypy never checks for that. Whitespace-dependent results are certainly incorrect.

Maybe this should be P1, but I still don't feel confident assigning priority labels here.

[injust]

Attrs is a red herring here.

Thanks, I suspected this but I must've done something wrong when minimalizing my example.

Also note that this only works when the file has from __future__ import annotations (otherwise this will be a runtime error, if my in-brain interpreter is not yet dead today), but mypy never checks for that.

You're right, I had from __future__ import annotations in my actual code but accidentally removed it.