Error with mixing str and pathlib.Path in command line arguments list

Bug Report

mypy raises error if list of command line arguments (passing to subprocess.call) contains items of different types (for example, str and pathlib.Path). It can be fixed by adding type hint to variable, but it's too annoying.

To Reproduce

import pathlib
import subprocess

cmd = [pathlib.Path('bash'), '-c', 'echo Hello']
subprocess.call(cmd)

Expected Behavior

mypy should not raise any error.

Actual Behavior

main.py:5: error: Argument 1 to "check_call" has incompatible type "List[object]"; expected "Union[Union[str, bytes, PathLike[str], PathLike[bytes]], Sequence[Union[str, bytes, PathLike[str], PathLike[bytes]]]]"
Found 1 error in 1 file (checked 1 source file)

Why can't mypy recognize cmd type as List[Union[pathlib.Path, str]], not List[object]?

Environment

• Mypy version used: 0.961
• Python version used: 3.10
• Operating system: Linux

Start with the provided Python reproducer and the typing of subprocess.call, then trace how mypy infers the type of a mixed list containing pathlib.Path and str. Confirm the change with a regression test using the shown command-line argument list, and verify that mypy reports no error while existing subprocess argument checks remain intact.