rust/src/test/compile-fail/issue-19883.rs

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

#![feature(associated_types)]

trait From<Src> {
    type Output;

    fn from(src: Src) -> <Self as From<Src>>::Output;
}

trait To {
    // This is a typo, the return type should be `<Dst as From<Self>>::Output`
    fn to<Dst: From<Self>>(self) -> <Dst as From<Self>>::Dst {
    //~^ error: the trait `core::kinds::Sized` is not implemented
        From::from(self)
    }
}

fn main() {}