rust/src/test/compile-fail/trait-cast.rs

// Copyright 2012 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.

trait foo<T> { }

fn bar(x: foo<uint>) -> foo<int> {
    return (x as foo::<int>);
    //~^ ERROR mismatched types: expected `@foo<int>` but found `@foo<uint>`
    //~^^ ERROR mismatched types: expected `@foo<int>` but found `@foo<uint>`
    // This is unfortunate -- new handling of parens means the error message
    // gets printed twice
}

fn main() {}