Bug Report

Hi everyone, thanks for all the work on mypy, I love this tool! 👏

I run into an issue with this code:

def foo(values: list[dict]) -> dict | None:
    return max(values, default=None, key=lambda entry: entry.get("value", 0))

See playground: https://mypy-play.net/?mypy=latest&python=3.12&gist=3daadb92c263a8447595aa7640a04599

Expected Behavior:

mypy should not report any errors

Actual Behavior

mypy reports an error:

Item "None" of "dict[Any, Any] | None" has no attribute "get"

Environment

• Mypy version used: mypy 1.10.1 (compiled: yes)
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: Python 3.12.2

Additional Details

I found this issue from 2019, which seems to be the same issue: #6460

Here people reported that it was an issue with typeshed, which was fixed in typeshed with this PR: python/typeshed#2833

I checked current trunk for typeshed and cannot spot any issue with the stubs for max(), the type correctly seems to indicate that the key function has nothing to do with the type of the default parameter: https://github.com/python/typeshed/blob/d482d4e83c9d247e79c87d954a9ccb11f85bfc37/stdlib/builtins.pyi#L1515-L1516

So while it seems this issue was once fixed it the past, it looks like it might have reappeared through a different cause.