When I have an interface with a generic as such:

```
   interface I1<S> {
      a: string;
      b: genericType<S>
}

```

and try to extract type of property `a` using `I1['a']`, typescript throws the following error:

`TS2314: Generic type 'I1<S>' requires 1 type argument(s).`

Should this not be fine since the extracted property type is not actually dependent on `<S>`? Either I am failing to understand how Typescript actually works or this should indeed be okay.

[Playground Link](https://www.typescriptlang.org/play/?ssl=12&ssc=2&pln=1&pc=1#)