Poor inference of dict literal when dict type is unioned with certain types

Bug Report

To Reproduce

https://mypy-play.net/?mypy=master&python=3.11&gist=5cf1ab002a6dc63c5013fa0f6a00ba4d

Expected Behavior
I expect the dict literal to be inferred as dict[str, str |int] when passed to both foo and bar

Actual Behavior
It's inferred as dict[str, object] when passed to foo, which causes a false positive.

Note that the inference depends on the type you union the dict with. E.g. if you replace Iterable[tuple[str] with list[tuple[str]] you get the expected inference.

Your Environment

• Mypy version used: Tried 1.0.0, 1.0.1, 1.1.1, 1.2.0 and master in the playground, all have the same behavior
• Mypy command-line flags: See playground
• Mypy configuration options from mypy.ini (and other config files): See playground
• Python version used: 3.11

リンクされている mypy playground の例を、Python 3.11 と報告されているバージョンで開始し、foo と bar で推論結果が異なることを再現します。Iterable[tuple[str]] と list[tuple[str]] を含むユニオンに対する dict リテラルの推論動作を追跡します。両方の呼び出しで dict が dict[str, str | int] と推論され、このケースを回帰テストでカバーできれば完了です。