| //@ revisions: current next |
| //@ ignore-compare-mode-next-solver (explicit revisions) |
| //@[next] compile-flags: -Znext-solver |
| |
| #![feature(unsize)] |
| |
| use std::marker::Unsize; |
| |
| pub trait CastTo<T: ?Sized>: Unsize<T> { |
| fn cast_to(&self) -> &T; |
| } |
| |
| impl<T: ?Sized, U: ?Sized + Unsize<T>> CastTo<T> for U { |
| fn cast_to(&self) -> &T { |
| self |
| } |
| } |
| |
| impl<T: ?Sized> Cast for T {} |
| pub trait Cast { |
| fn cast<T: ?Sized>(&self) -> &T |
| where |
| Self: CastTo<T>, |
| { |
| self |
| } |
| } |
| |
| pub trait Foo: CastTo<[i32]> {} |
| impl Foo for [i32; 0] {} |
| |
| fn main() { |
| let x: &dyn Foo = &[]; |
| let x = x.cast::<[i32]>(); |
| //~^ ERROR: the trait bound `dyn Foo: CastTo<[i32]>` is not satisfied |
| } |
