False-positive [attr-defined] when importing classes and functions from a file with the same name as the parent package

[ArrayBolt3]

Bug Report

Suppose you have the following directory tree:

thebug/
thebug/run.py
thebug/__init__.py
thebug/thebug.py

Attempting to import anything from thebug.py (using from thebug import whatever) will cause mypy to complain error: Module "thebug" has no attribute "whatever" [attr-defined].

To Reproduce

1. mkdir thebug
2. cd thebug
3. touch __init__.py
4. vim thebug.py and type in the following contents:

class A:
    def __init__(self) -> None:
        self.val = "a"

5. vim run.py and type in the following contents:

from thebug import A
var: A = A()
print(var.val)

6. Run it to make sure it works:

$ python3 run.py
a

7. Type-check it:

mypy run.py

Actual Behavior

$ mypy run.py
run.py:1: error: Module "thebug" has no attribute "A"  [attr-defined]
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.16.1
• Mypy command-line flags: none, as shown above
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.12.3