rust/src/test/ui/cycle-projection-based-on-where-clause.rs
2018-12-25 21:08:33 -07:00

26 lines
674 B
Rust

// Example cycle where a bound on `T` uses a shorthand for `T`. This
// creates a cycle because we have to know the bounds on `T` to figure
// out what trait defines `Item`, but we can't know the bounds on `T`
// without knowing how to handle `T::Item`.
//
// Note that in the future cases like this could perhaps become legal,
// if we got more fine-grained about our cycle detection or changed
// how we handle `T::Item` resolution.
use std::ops::Add;
// Preamble.
trait Trait { type Item; }
struct A<T>
where T : Trait,
T : Add<T::Item>
//~^ ERROR cycle detected
//~| ERROR associated type `Item` not found for `T`
{
data: T
}
fn main() {
}