String templates doesn't work with nested generics and keyof

[f3oall]

🔎 Search Terms

String templates doesn't work with nested generics and keyof

🕗 Version & Regression Information

5.2.2, 5.3

⏯ Playground Link

https://www.typescriptlang.org/play?ts=5.3.2#code/JYOwLgpgTgZghgYwgAgIIB4AqyIA9IgAmAzsgEoQID2Uh6xYUoA5gDTINMjMB8yA3gChkyEBAYRCALmSZBAX0FKYAVxAIwwKiGRwsOfBCKkM-YNI6MW8njwAUYGZgCUA4cgBGD9gHJzP1wB6QORmKipCdy8wXwBafyCQgCEVZgB+BUFVdU1tT308AhI0dDgQAE9bByd2YhpHZABrCHKqGFkAbR8xCUIfAF1kADJLLmZkAB9kAANYgBJ+Ztb2zC6eyD7Bkc5radchTKA

💻 Code

interface A<T extends Record<string, string> {
  nested: T
}


function a<T extends A<{id: string}>>(t: T) {
  b(t, 'id') // good
  b(t, '-id') // Bug?
}
function b<T extends A<any>>(t: T, sort: keyof T['nested'] & string | `-${keyof T['nested'] & string}`) {

}

🙁 Actual behavior

Template string doesn't work as expected

🙂 Expected behavior

The example should compile without error

Additional information about the issue

No response

[ahejlsberg]

Yeah, that ought to work. Here's a simpler repro:

function a<T extends {id: string}>() {
  let x: keyof T & string | `-${keyof T & string}`;
  x = "id";  // Ok
  x = "-id";  // Error, but should be ok
}