#![feature(associated_type_defaults)] | |
use std::ops::{Index}; | |
trait Hierarchy { | |
type Value; | |
type ChildKey; | |
type Children = dyn Index<Self::ChildKey, Output=dyn Hierarchy>; | |
//~^ ERROR: the value of the associated types `Value` (from the trait `Hierarchy`), `ChildKey` | |
fn data(&self) -> Option<(Self::Value, Self::Children)>; | |
} | |
fn main() {} |