Imports that shadow names cannot be made to type-check

Bug Report

--allow-redefinition does not come into effect for imports that shadow a previous import with incompatible types. Even if the previous name is first del'd the error still persists, whether --allow-redefinition is enabled or not.

I found this during work on https://github.com/python/typeshed/pull/11374#issuecomment-1968999481. The upstream library first does a star-import re-exporting hundreds of names, then shadows at least one of them with a wrapper type. The star-import cannot be rewritten due to the sheer number of imported names, but then the name shadowing cannot be prevented.

To Reproduce

# $ tree .
# .
# ├── bar.py
# ├── foo.py
# ├── __init__.py
# └── py.typed

# foo.py & bar.py
class Repository:
    pass

# __init__.py
from .foo import Repository
del Repository  # this doesn't work
from .bar import Repository

# Both fails in the same way:
# $ mypy .
# $ mypy --allow-redefinition .
#
# __init__.py:3: error: Incompatible import of "Repository" (imported name has type "type[p.bar.Repository]", local name has type "type[p.foo.Repository]")  [assignment]
# Found 1 error in 1 file (checked 3 source files)

One-file example:

• Gist URL: https://gist.github.com/mypy-play/826f927d282282e8f8d51bc4411b4b94
• Playground URL: https://mypy-play.net/?mypy=master&python=3.12&flags=allow-redefinition&gist=826f927d282282e8f8d51bc4411b4b94

from hashlib import md5 as foo
del foo
from sys import path as foo

Expected Behavior

No errors.

Actual Behavior

main.py:3: error: Incompatible import of "foo" (imported name has type "list[str]", local name has type "Callable[[Buffer, DefaultNamedArg(bool, 'usedforsecurity')], _Hash]")  [assignment]
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.8.0 & master branch
• Mypy command-line flags: none & --allow-redefinition
• Mypy configuration options from mypy.ini (and other config files): n/a
• Python version used: 3.11 & 3.12

Beginne damit, das Problem mit init.py, foo.py und bar.py unter Verwendung der gezeigten mypy-Befehle einschließlich --allow-redefinition zu reproduzieren. Verfolge, wie mypy den gelöschten ersten Import und den inkompatiblen Ersatz behandelt, und füge anschließend einen Regressionstest hinzu, der beide Beispiele abdeckt. Als abgeschlossen gilt die Aufgabe, wenn die Importe in beiden Flag-Konfigurationen fehlerfrei typgeprüft werden.