Bug Report

After upgrading to mypy 0.971 I am not longer getting any error messages, I suspect this is related due to virtualenv issues as our CI (that does not use virt envs), DOES surface errors.

To Reproduce

(Write your steps here:)

1. Setup virtualenv
2. Run mypy against a specific module
3. get no errors

Expected Behavior

I expected to get the same errors than on 0.960

Actual Behavior

No errors / issues are reported at all.

Your Environment

• Mypy version used: 0.971
• Mypy command-line flags:
• Mypy configuration options from mypy.ini (and other config files):

[mypy]
python_version = 3.9
warn_redundant_casts = True
warn_unused_ignores = True
mypy_path = typings
show_error_codes = True

[mypy-*]
strict = True
disallow_untyped_calls = True
disallow_untyped_defs = True
check_untyped_defs = True
warn_return_any = True
ignore_missing_imports = True

• Python version used: 3.9
• Operating system and version: MacOS Monterey 12.4