Microsoft/TypeScript

TS is overly picky when declaring a class constructor type

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#29,707 创建于 2019年2月3日

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 (11 评论) (6 反应) (0 负责人)TypeScript (48,455 star) (6,726 fork)batch import
BugDomain: classesGood First IssueHelp Wanted

描述

TypeScript Version: 3.4.0-dev.20190202

Search Terms: class, extend, constructor, any[]

Code

type ClassConstructor = new(...args: any[]) => {}

function mixin<C extends ClassConstructor>(Class: C) {
  return class extends Class {}
}

Expected behavior:

I should be able to replace ...args: any[] with ...args: unknown[], or any other signature.

Actual behavior:

Error: Type 'C' is not a constructor function type. [2507]

Playground Link: https://www.typescriptlang.org/play/index.html#src=type%20ClassConstructor%20%3D%20new(...args%3A%20unknown%5B%5D)%20%3D%3E%20%7B%7D%0D%0A%0D%0Afunction%20mixin%3CC%20extends%20ClassConstructor%3E(Class%3A%20C)%20%7B%0D%0A%20%20return%20class%20extends%20Class%20%7B%7D%0D%0A%7D

贡献者指南

技术栈
typescript
领域
tooling
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
TypeScript fundamentalsgeneric constraintsclass constructor types
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
65
研究方向
Investigate the TypeScript compiler source code, particularly the `checker.ts` file where constructor type constraints are validated. Review the comments in the issue for potential solutions and test cases. The fix likely involves relaxing the constraint for `new(...args: unknown[]) => {}` to be accepted as a constructor type.
TS is overly picky when declaring a class constructor type · Microsoft/TypeScript#29707 | Good First Issue