Regress: Deep recursive type transform gives any

[cevek]

TypeScript Version: 3.3.0-dev.20190125

Search Terms:

It works in 3.1.6, but in 3.2 and 3.3 it gives any

Code

export type Transform<T> = { [K in keyof T]: Transform<T[K]> };
interface User {
 avatar: string;
}

interface Guest {
 displayName: string;
}

interface Product {
 users: (User | Guest)[];
}
declare var product:Transform<Product>;
product.users // any[] 

Expected behavior:
Transform<(User | Guest)>[]
Actual behavior:
any[]

[ahejlsberg]

Duplicate of #27881 and any results from fix in #27911. With #26063 we map arrays and tuples to transformed arrays and tuples, but because we have to eagerly resolve the element type in order to instantiate an Array<T>, we end up triggering a circularity and resolve to any.

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.