rust/src/test/compile-fail/cross-borrow-trait.rs
Nick Cameron 7f72884f13 Remove cross-borrowing for traits.
Closes #15349

[breaking-change]

Trait objects are no longer implicitly coerced from Box<T> to &T. You must make an explicit coercion using `&*`.
2014-09-03 08:32:35 +12:00

23 lines
782 B
Rust

// Copyright 2012-2013-2014 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.
// Test that cross-borrowing (implicitly converting from `Box<T>` to `&T`) is
// forbidden when `T` is a trait.
struct Foo;
trait Trait {}
impl Trait for Foo {}
pub fn main() {
let x: Box<Trait> = box Foo;
let _y: &Trait = x; //~ ERROR mismatched types: expected `&Trait`, found `Box<Trait>`
}