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如何强制编译器不重载toString？我得到的最接近的是使用never类型，但从来没有被允许隐式赋值给var，编译器只会在变量完成某些操作时发出抱怨。谁会记得显式声明toString调用为字符串？为toString强制执行类型签名
type ArrayToStringMethod = {
(this: { join(a: string): string, length: number }): string
(this: any): never // if this overload isn't here typescript uses
// Object.toString automatically.
}
type ArrayDontMutate<t> = {
toString: ArrayToStringMethod
readonly [index: number]: t
readonly length: number
} &
Pick<
Array<t>,
'find' |
'map' |
//'join' | deliberately removed to make toString fail
'some' |
'slice' |
'concat' |
'reduce'>
let a:ArrayDontMutate<string> =['a','b','c'] as any
let b = a.toString() //should fail no join method. b is the never type