Any is excessively used as outer context for inference

Consider this example:

from typing import Any
  
def foo(**kwargs: Any) -> None: ...

foo(bar=reveal_type([1])) # Revealed type is List[Any]

Such behavior causes many false negatives for plugins that provide precise type checking for various ORMs, this includes SQLAlchemy plugin, our internal plugins, and likely Django plugin.

My guess this was added so that an empty list in Any context is inferred as List[Any] instead of List[<nothing>], but I think this is counterproductive. If empty collections cause issues for plugins they can easily work around using private APIs to re-infer argument type in generated precise context (for example using has_uninhabited_component() and ctx.api.accept()). Or maybe we can provide public API for inference.

mypy で例を再現し、**kwargs: Any の呼び出しにおいて外側の Any コンテキストが reveal_type([1]) にどのような影響を与えるかを調査します。issue で言及されているプラグインの再推論 API（has_uninhabited_component() と ctx.api.accept() を含む）を確認します。完了条件は、一貫した推論動作または公開 API について合意し、それを実装することです。例と影響を受けるプラグインシナリオに対するリグレッションカバレッジも含みます。