Bug Report

A function returning NotImplementedType cannot return NotImplemented if strict=True.

(A clear and concise description of what the bug is.)

To Reproduce

from types import NotImplementedType

def foo() -> NotImplementedType:
    return NotImplemented

Expected Behavior

Type checks even with --strict

Actual Behavior

main.py:4: error: Returning Any from function declared to return "_NotImplementedType"  [no-any-return]
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.15.0
• Mypy command-line flags: --strict
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.12