Bug Report

The original bug report is optuna/optuna#4404.
I tried to make a minimal reproducible example and found that checking the following code with the latest mypy takes about 1 minute.

To Reproduce

import numpy as np
from typing import Any

x: np.ndarray[Any, np.dtype[np.floating]] = np.asarray([1, 2, 3])
1 + x * (1 + x * (1 / 2 + x * (1 / 6 + x * (1 / 24 + x / 120))))

Adding terms as follows seems to increase execution time exponentially.

1 + x * (1 + x * (1 / 2 + x * (1 / 6 + x * (1 / 24 + x * (1 / 120 + x / 720)))))

Expected Behavior

The execution takes a few seconds.

Actual Behavior

$ time mypy exp.py 
Success: no issues found in 1 source file

real	1m17.655s
user	0m55.657s
sys	0m0.892s

Your Environment

• Mypy version used: 1.1.1
• Mypy command-line flags: No flags
• Mypy configuration options from mypy.ini (and other config files): No configs
• Python version used: 3.9.4