Incorrect method name in cached overload "note" messages

[pmantion]

Bug Report

When mypy displays "note" messages for overloaded __init__ methods with cache enabled, it incorrectly shows the class name instead of __init__. This only occurs when the overloaded class is defined in a stub file (.pyi).

To Reproduce

# file:example_stubs.pyi
from typing import overload

class Foo:
    @overload
    def __init__(self) -> None: ...
    @overload
    def __init__(self, bar: str | None) -> None: ...

# file: example.py
from example_stubs import Foo

Foo(wrong_arg_name=1)

Steps to reproduce:

rm -rf .mypy_cache
python -m mypy example.py  # First run (no cache)
python -m mypy example.py  # Second run (with cache)

Expected Behavior (without cache)

Output of Mypy is:

example.py:3: error: No overload variant of "Foo" matches argument type "int"  [call-overload]
example.py:3: note: Possible overload variants:
example.py:3: note:     def __init__(self) -> Foo
example.py:3: note:     def __init__(self, bar: str | None) -> Foo
Found 1 error in 1 file (checked 1 source file)

Actual Behavior (with cache)

When the Mypy cache is present, the output of Mypy is:

example.py:3: error: No overload variant of "Foo" matches argument type "int"  [call-overload]
example.py:3: note: Possible overload variants:
example.py:3: note:     def Foo(self) -> Foo
example.py:3: note:     def Foo(self, bar: str | None) -> Foo
Found 1 error in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.18.2
• Mypy command-line flags: (none)
• Mypy configuration options from mypy.ini (and other config files): (none)
• Python version used: 3.13.7