如何在Kotlin中检查泛型? [英] How to check generic type in Kotlin?

问题描述

我上课

class Generic<T : SuperType>()

此代码不正确

fun typeCheck(s: SuperType): Unit {
            when(s){
                is T -> //do some thin
            }
        }

但是将s强制转换为T s as T类型显示警告-不安全的强制转换.
如何检查s是T类型?

but cast s to type T s as T show warning - unsafe cast.
How check that s is type T?

推荐答案

泛型类型在运行时未在JVM上实现统一化，因此Kotlin中无法做到这一点.该警告是正确的，因为在强制转换完成后编译器不可能生成任何会失败的指令，因此不进行强制转换，这意味着程序以后可能会或可能不会中断.

Generic types are not reified on the JVM at runtime, so there's no way to do this in Kotlin. The warning is correct because the compiler can't possibly generate any instruction that will fail when the cast is done, so the cast is unchecked, meaning that the program may or may not break at some point later instead.

一个可能有用的相关功能是已修改类型参数在内联函数中.但是，类不能具有类型化的类型参数，因此，如果您对用例进行详细说明，我可以尝试帮助您实现您似乎需要的东西.

A related feature which might be of use is reified type parameters in inline functions. Classes can't have reified type parameters though, so if you elaborate a bit more on your use case, I can try helping you achieve what you seem to need.

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