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// 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(specialization)]
// Make sure we can't project defaulted associated types
trait Foo {
type Assoc;
}
default impl<T> Foo for T {
type Assoc = ();
}
impl Foo for u8 {
type Assoc = String;
}
fn generic<T>() -> <T as Foo>::Assoc {
// `T` could be some downstream crate type that specializes (or,
// for that matter, `u8`).
() //~ ERROR mismatched types
}
fn monomorphic() -> () {
// Even though we know that `()` is not specialized in a
// downstream crate, typeck refuses to project here.
generic::<()>() //~ ERROR mismatched types
}
fn main() {
// No error here, we CAN project from `u8`, as there is no `default`
// in that impl.
let s: String = generic::<u8>();
println!("{}", s); // bad news if this all compiles
}
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