Branded string literals revert to string in some cases #60990
Description
🔎 Search Terms
If I create a branded string literal it seems to respect the string literal in the basic case of assigning to a property, however it loses this information and just reverts to string when assigning to a property or in a template string.
It makes sense that the brand object needs to be dropped in these cases, but rather than converting to string, it should convert to the narrower literal type.
🕗 Version & Regression Information
- This is the behavior in every version I tried, and I reviewed the FAQ for entries about branded string
⏯ Playground Link
💻 Code
type MyLiteral<S extends string> = S & {_brand: {}};
const a = 'a' as MyLiteral<'a'>;
const x: 'a' = a; // works!
const y: 'a' = `${a}`; // fails!
const z: {a: number} = {[a]: 8} // fails!🙁 Actual behavior
For y and z, the types don't match because a is converted to string rather than 'a'
🙂 Expected behavior
The types should match in all 3 cases, x, y, z
Additional information about the issue
No response