Reactjs 属性子项是否将被覆盖？

我有以下反应组件：

export default function ElevationScroll({children}: PropsWithChildren<{ children: ReactElement }>) {

    const trigger = useScrollTrigger({
        disableHysteresis: true,
        threshold: 0
    });


    return React.cloneElement(children, {
        elevation: trigger ? 3 : 0,
    });
}

在component参数中，我将

{children:ReactElement}

作为泛型类型传递，该泛型类型扩展为：

type PropsWithChildren<{ children: ReactElement }> = { children: ReactElement } & { children?: ReactNode };

type-PropsWithChildren={children:ReactElement}&{children？:ReactNode}；

---

为什么允许定义属性

子属性两次

提醒：
{a:string}&{a:number}
结果类型
从不

type PropsWithChildren<{ children: ReactElement }> = { children: ReactElement } & { children?: ReactNode };

type Prop<P> = P & { a: number };

// {a: string} & { a: number } = never
const bad: Prop<{a:string}> = {a: '5'} // Type 'string' is not assignable to type 'never'

// { a: Number } & { a: number } 
const obj: Prop<{a:Number}> = {a: 5} // GOOD

type ReactNode = ReactChild | ReactFragment | ReactPortal | boolean | null | undefined;
type ReactChild = ReactElement | ReactText;

// Therefore
type ReactNode = ReactElement | ....