Smarter errors around `Function.length`

I don't know how often other people have encountered this, but here goes: In the same vein as our uncalled function checks, most usages of Function.length are probably an error. Here's a toy example that just bit me:

declare function getResult(): string[];
for (let i = 0; i< getResult.length; i++) {
  getResult().slice(0, i).map(x => console.log(x));
}

Minimally, I think we could suggest that if a function returns something with a length property, and the function's length property is inspected instead, we could probably mark it as suspect.

まず、TypeScript コンパイラーに既にある未呼び出し関数のチェックを調べ、次に関数プロパティへのアクセスがどのように解析されるかを追跡します。関数の結果が length プロパティを持つ場合に Function.length を検査する際の意図された診断上の境界を定義し、その使用が疑わしいと見なされる条件を示すカバレッジを追加します。