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.

首先检查 TypeScript 编译器中现有的未调用函数检查，然后跟踪函数属性访问是如何分析的。当函数结果具有 length 属性时，确定检查 Function.length 的预期诊断边界，并添加覆盖范围，展示何时会将该用法视为可疑。