Misleading error message

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Issue 类型
缺陷
描述清晰度
基本清楚
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技术栈
typescript
领域
compilers

调研方向

首先,使用提供的代码在链接的 TypeScript Playground 中重现赋值诊断,然后跟踪如何为 itemfields 成员选择不兼容消息。完成的标准是诊断将 fields 识别为有问题的成员,并且相关的回归覆盖测试通过。

由索引模型根据 Issue 内容生成。

描述

Domain: Error Messages Help Wanted Possible Improvement
🔎 Search Terms

Misleading error message

🕗 Version & Regression Information

I think in all version but I just tries 5.2.2 and 5.3.0-beta

⏯ Playground Link

https://www.typescriptlang.org/play?#code/JYOwLgpgTgZghgYwgAgPIAczAPYgDwAqAfMgN4CwAUMjcsJALYD8AXMgQNxW3IzAQAbACYBnVsgAUAawgBPbDHYBKDgHpVyAK4jQAc2QADEWCh6A2gF0DyOCORhZ6FAAtoKAO7ZNw5AzgzkdGwRHQAjARQwV3swMBsQ4F0QBghwKgBfKgQBWzsCCGMAIVsIQmQIAA9IEFFkbFCAKwgEOIBeOsbmsBIKalpIYwkwNgwsXEIiJTJMyhnQSFhEFAARODA4Mm5aITW4NmNTEF0uWayckPYCsABhZ2AfSura-KKSvFX1nq2aAbAhkcwOHwHzgk2mGSoVAicViw0urxEKHaIAg7nhNzuwgkKiAA

💻 Code
interface Option<T> {
    item?: T;
    fields?: (keyof T);// using `string[]` as type here would make possible the ttt assignment
}
class TestBase<T extends object = object> {
    test(t: Option<T>) {}
}
interface Data {
    data: string;
}
class TestChild extends TestBase<Data> {
    test(t: Option<Data>) {}
}

let ttt: TestBase = new TestChild();
🙁 Actual behavior

In the error message if I hover over ttt it states that the item member is incompatible, but I think it is not the problem but the fields member. If I change its type from (keyof T)[] to type string[] the error is solved but as I see this means the error message was misleading.

🙂 Expected behavior

The error message should state that the fields member is the problematic

Additional information about the issue

I think the problem is that fields member has type keyof object in base class (TestBase) which maybe results in type never and in derivative class (TestChild) the fields results in "data" which is defineatly not assignable to never type.
Although I have years of experience in ts it can surprise me sometimes. :)

ps: Sorry if it is a known issue or expected behavior. Then please point me out to the corresponding documentation

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