=== tests/cases/compiler/typedGenericPrototypeMember.ts ===
class List<T> {
>List : List<T>
>T : T

   add(item: T) { }
>add : (item: T) => void
>item : T
>T : T
}

List.prototype.add("abc"); // Valid because T is instantiated to any
>List.prototype.add("abc") : void
>List.prototype.add : (item: any) => void
>List.prototype : List<any>
>List : typeof List
>prototype : List<any>
>add : (item: any) => void