*
     * ```kt
     * fun usage(action: String.(Int) -> String) {
     *   "hello".<expr>action</expr>(10)
     * }
     * ```
     *
     * The user might want to know the type of the `action` callback. If we always return null for the named references,
     * we won't be able to handle this request, and just return null. So the user will only be able to see the type