Mapped types, trouble with array member?

[JasonKleban]

I'm thinking this is a bug. The intention here is to create a parallel nested type. I'm having trouble with the array member here - there are some type restrictions being enforced, but not enough. myValidation.c shouldn't be allowed to be an array at all, let alone an array of string, but it seems to allow an array of any type there.

interface ValidationRule<T, RootState extends object> {
    isValid: (value: T, state?: RootState) => boolean
}

type Validated<State extends object, Root extends object = State> = {
    [Member in keyof State]:
        Validated<State[Member], Root>
        | ValidationRule<State[Member], Root>;
}

interface AppState {
    a: number,
    b: string,
    c: number[]
}

var myAppState: AppState = {
    a: 5,
    b: "Hello",
    c: [7, 11]
}

var myValidation: Validated<AppState> = {
    a: {
        isValid: (v, s) => true
    },
    b: {
        isValid: (v) => true
    },
    // c: {} //does error, good
    // c: "" //does error, good
    c: ["Why", "doesn't", "this", "error"] // <-- should error
}

Playground link

Also, is there a way to see the mapped type in its expanded form?

[ghost]

Probably has to do with the recursion in Validated. Here's a simplified example:

type Validated<State extends object> = {
    [Member in keyof State]: Validated<State[Member]>;
}
const c: Validated<number[]> = ["why", "doesn't", "this", "error"];

[mhegazy]

looks like a duplicate of #12769

[mhegazy]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.