如何在Typescript中用字符串键和特定对象类型写入对象的类型？

Question

export type Distributions = {
    [index: string]: {
        distributions: Array<number>,
        histogramUpperLimit: number,
        nonZeroUser: number,
        percentiles: Array<number>
    }
};

let test: Distributions = {
    "thisIsAID": {
        distributions: 1238
    }
};

它应该抛出错误，但它没有，我写的不正确？