Bug Report

🔎 Search Terms

cannot be named symbol TS4058

🕗 Version & Regression Information

• This changed between versions 4.7.4 and 5.2.0-dev.20230710
• This is the behavior in every version I tried, and I reviewed the FAQ for entries about "cannot be named"

⏯ Playground Link

Two files involved, so can't make a playground link

💻 Code

declaration=true

// fileA.ts
export const $SYM = Symbol("$SYM");
export const OBJ = { [$SYM]: 42 };

// fileB.ts
import type { $SYM, OBJ } from "./fileA";
export function func(obj: typeof OBJ, sym: typeof $SYM) {
  return [obj, sym];
}

🙁 Actual behavior

Error: Return type of exported function has or is using name '$SYM' from external module "fileA" but cannot be named.

🙂 Expected behavior

The expectation was that it compiles. Because if I use a string constant literal instead of the symbol, it works.

P.S. In version 4.7.4 it worked, BUT it worked incorrectly: it generated declarations like function func(obj: { [$SYM]: number }) without actually importing $SYM, so it treated $SYM as a string (I think it was a bug). Now that bug is fixed, but there is still no way to generate declarations for similar situations (and as you can see, importing $SYM explicitly doesn't help).