TS2536 when deep remapping

[klarezz]

Bug Report

🔎 Search Terms

TS2536: Type cannot be used to index

🕗 Version & Regression Information

v4.9.5

⏯ Playground Link

Playground Link

💻 Code

type Obj = {
  a: {
    b: {
      c: unknown
    }
  }
};

type ReMap = {
  [P in keyof Obj]: {
    [M in keyof Obj[P]]: Obj[P][M]["c"]
  }
};

🙁 Actual behavior

Code below throws TS2536: Type "c" cannot be used to index type 'Obj[P][M]'

🙂 Expected behavior

No error?

Related?

Could be related to #21760

[klarezz]

@MartinJohns, I updated the issue, could you please explain what I'm doing wrong?

[RyanCavanaugh]

I think this is just a duplicate of the one you linked.

Anyway this code is equivalent and works well:

type Obj = {
  a: {
    b: {
      c: string
    }
  }
};

type GetC<T> = T extends { c: infer O } ? O : never;

type ReMap = {
  [P in keyof Obj]: {
    [M in keyof Obj[P]]: GetC<Obj[P][M]>;
  }
};

[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.