Declaration emit writes [SymbolConstructor.iterator] as a computed key when a SymbolConstructor value is in scope #65379

🔎 Search Terms

SymbolConstructor declaration emit, TS2693 d.ts, Symbol.iterator computed property d.ts, well-known symbol declaration emit

🕗 Version & Regression Information

Regression in 7.x.

• Fails: 7.0.1-rc, 7.0.2, 7.1.0-dev.20260708.3 (first 7.1 nightly), 7.1.0-beta, 7.1.0-dev.20261106.1
• Works: 5.9.3, 6.0.3

⏯ Playground Link

https://www.typescriptlang.org/play/v2/?ts=7.1.0-dev.20261108.1#code/v2/N4IghgxgLglgbgUwGIwDYJALhAegO4D2ATgNYDOADpAjmURDjAHYAmCAHgHRRkgA0IAGZoEvTKHzFyVCDR4QCTYQHNOAKzKKsIYAB0mAAgO6QCgLYURRAPIVYisicwG9ho8ZBQwRZQihOPUSYOf359dw8zAhYAV3QAkyCQkz5w9xMyKCIYaACsmIRUtyMTNghUbzB7JjyiArSAX30mpn5cQlJKalp6RlYObjFTBygDAGUDAF5xgE8zACMCVABufQ4KYlGFJkyDIjAmXymXAwAqAG0xucXUThgoBH2oYgBdAAoAShOZmARUFgMAEZlgYGqDVq0GgIyH8ENAYFpxCANmR7gimABhJYxMytTCAgQotGKAAyzAQADkcfNHlgCSAYeh4Yoxl4iFAsagcXj6Yy4dVWd4oGTglSFrT8VCQIgiKjEQAmBpAA

(Playground v2, 7.1.0-dev.20261108.1: Emit → src/index.d.ts shows [SymbolConstructor.iterator](). Same project on 6.0.3, correct [S.iterator](): https://www.typescriptlang.org/play/v2/?ts=6.0.3#code/v2/N4IghgxgLglgbgUwGIwDYJALhAegO4D2ATgNYDOADpAjmURDjAHYAmCAHgHRRkgA0IAGZoEvTKHzFyVCDR4QCTYQHNOAKzKKsIYAB0mAAgO6QCgLYURRAPIVYisicwG9ho8ZBQwRZQihOPUSYOf359dw8zAhYAV3QAkyCQkz5w9xMyKCIYaACsmIRUtyMTNghUbzB7JjyiArSAX30mpn5cQlJKalp6RlYObjFTBygDAGUDAF5xgE8zACMCVABufQ4KYlGFJkyDIjAmXymXAwAqAG0xucXUThgoBH2oYgBdAAoAShOZmARUFgMAEZlgYGqDVq0GgIyH8ENAYFpxCANmR7gimABhJYxMytTCAgQotGKAAyzAQADkcfNHlgCSAYeh4Yoxl4iFAsagcXj6Yy4dVWd4oGTglSFrT8VCQIgiKjEQAmBpAA)

💻 Code

// lib.ts
const S = Symbol;
export const range = { *[Symbol.iterator]() { yield 1; } };

// use.ts
import { range } from "./out/lib.js";
for (const x of range) console.log(x);

🙁 Actual behavior

tsc --declaration --emitDeclarationOnly --target esnext --outDir out lib.ts writes (7.0.2):

declare const S: SymbolConstructor;
export declare const range: {
    [SymbolConstructor.iterator](): Generator<number, void, unknown>;
};
export {};

7.1.0-beta and 7.1.0-dev.20261106.1 no longer emit declare const S but keep [SymbolConstructor.iterator].

tsc --noEmit --target esnext --module nodenext use.ts:

out/lib.d.ts(3,6): error TS2693: 'SymbolConstructor' only refers to a type, but is being used as a value here.
use.ts(2,17): error TS2488: Type '{ [x: number]: () => Generator<number, void, unknown>; }' must have a '[Symbol.iterator]()' method that returns an iterator.

With --skipLibCheck the TS2693 goes away but the TS2488 stays: consumers can no longer iterate range.

🙂 Expected behavior

A key that refers to a value. 5.9.3 and 6.0.3 emit [S.iterator](): Generator<number, void, unknown>;, and use.ts checks without errors. [Symbol.iterator] would be fine too.

Additional information about the issue

The emitter writes the interface name (SymbolConstructor) where it needs a value. Any value of type SymbolConstructor in scope triggers it (const S = Symbol, or a parameter s: SymbolConstructor). Only inferred object types are affected; a class with a [Symbol.iterator]() method is emitted correctly.

This was found with an AI-assisted differential testing tool; the repro and outputs above were re-run on the listed versions.