相关疑难解决方法(0)

常识表明,子类型在返回类型方面应该是协变的,但在参数类型方面应该是逆变的.因此,应该拒绝以下内容,因为严格协变的参数类型E.f:

interface C {
   f (o: C): void
}

interface D extends C {
   g (): void // give D an extra service
}

class E implements C {
   // implement f with a version which makes stronger assumptions
   f (o: D): void {
      o.g() // rely on the extra service promised by D
   }
}

// E doesn't provide the service required, but E.f will accept
// an E argument as long as I invoke …

我希望以下代码无法转换,因为B不应该是array.push的有效类型.我错过了什么？

class A {};
class B {};
const arr: A[] = [];
arr.push(new B());