False positive "Overloaded function signature 2 will never be matched: signature 1's parameter type(s) are the same or broader" when using Unions vs TypeVars

Bug Report
When overloading a function to specify it can return bytes if given only bytes objects, str if given only str objects, or either if given a mix of both, mypy incorrectly complains that AnyStr is the same or broader than Union[str, bytes].

Despite the warning, mypy does correctly match the Union[str, bytes] signature when appropriate

To Reproduce

Very simple test case:

from typing import overload, TypeAlias, Union, AnyStr, reveal_type
from collections.abc import Sequence
from random import choice

AllStr: TypeAlias = Union[bytes, str]

# Below produces "error: Overloaded function signature 2 will never be
# matched: signature 1's parameter type(s) are the same or broader
# [misc]"
@overload
def pick_three(choices: Sequence[AnyStr]) -> AnyStr: ...
@overload
def pick_three(choices: Sequence[AllStr]) -> AllStr: ...
def pick_three(choices: Sequence[AllStr]) -> AllStr:
    return choice(choices)

strings: tuple[str, ...] = ('abc', 'def')
byte_strings: tuple[bytes, ...] = (b'abc', b'def')
mixed_strings: tuple[AllStr, ...] = ('abc', b'def')

reveal_type(pick_three(strings))  # str
reveal_type(pick_three(byte_strings))  # bytes
reveal_type(pick_three(mixed_strings))  # Union[bytes, str], despite the warning

Some more example code on mypy Playground, with other related cases that work as expected.

Expected Behavior

Mypy does not warn that signature 2 cannot match, given it clearly is able to match based on the reveal_type(pick_three(mixed_strings)) output

Actual Behavior

main.py:39: error: Overloaded function signature 2 will never be matched: signature 1's parameter type(s) are the same or broader  [misc]
main.py:43: note: Revealed type is "builtins.str"
main.py:44: note: Revealed type is "builtins.bytes"
main.py:45: note: Revealed type is "Union[builtins.bytes, builtins.str]"

Your Environment

Seen on Debian with Python 3.11 and mypy 1.0.1 using --strict, and in mypy Playground with Python 3.11 and mypy 1.4.1 with default options.

Start by reproducing the example in main.py with Python 3.11 and mypy 1.4.1 or later, using the overloads and reveal_type calls shown in the report. The fix is done when the mixed-string call still reveals Union[bytes, str] while mypy no longer reports that overload signature 2 will never be matched.