"maximum semantic analysis iteration count" when combining nested dataclass and undefined field.

[jonathanslenders]

Bug Report

The following little snippet causes the following error:

test.py: error: INTERNAL ERROR: maximum semantic analysis iteration count reached

To Reproduce

Create the following file. I know several things are not correct in this file, but that's absolutely the purpose.

from dataclasses import dataclass

def func() -> None:
    @dataclass
    class RequestWriter:
        field: bool

        def func() -> None:
            something_not_defined

Run mypy over it. This is the output:

 $ mypy client1.py
Deferral trace:
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
    client1:11
client1.py: error: INTERNAL ERROR: maximum semantic analysis iteration count reached
client1.py:10: error: Method must have at least one argument
Found 2 errors in 1 file (errors prevented further checking)

Expected Behavior

Mypy should probably point out that:

• something_not_defined is not defined.

Your Environment

• Mypy version used: 0.910
• Mypy command-line flags: None
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.9.5
• Operating system and version: Ubuntu 20.04.1

[AlexWaygood]

Thanks for the report! I'm going to close this as a duplicate of #8703