declaration emit depends on checker assignment; a type alias becomes any with no error #64998

🔎 Search Terms

singleThreaded, --checkers, checker pool, checkers declaration any, nondeterministic declaration, circularly references itself keyof, TS2456

🕗 Version & Regression Information

• This is the behavior in every version multi-threaded I tried, back to 7.0

⏯ Playground Link

https://tsgo.sxzz.dev/#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

💻 Code

status.ts

import type { Key } from "./types";
 
export class StatusClass {
  RUNNING: Status = "RUNNING";
  [key: string]: Status;
}
 
export type Status = keyof StatusClass | "";
 
export const statusFromAPI: { [key: Key]: Status } = {};

consumer.ts

import { statusFromAPI } from "./status";
 
export const current = statusFromAPI["RUNNING"];

types.ts:

export type Key = string;

🙁 Actual behavior

The consumer.d.ts output gets incorrectly inferred as any:

export declare const current: any;

🙂 Expected behavior

Both TS6 and --singleThreaded emit the correct type:

export declare const current: import("./status").Status;

Additional information about the issue

The emitted type depends on how many checkers there are, which really means how the files are split across them. Status below means import("./status").Status. Every run exits 0 with no diagnostics:

Each configuration gives the same result on every run (10 of 10 runs of the 7.1.0-beta default were identical), so this comes from how files are partitioned, not from a race. The .d.ts silently loses the type, and the build gives no sign that anything went wrong.