45 lines
1.1 KiB
Rust
45 lines
1.1 KiB
Rust
// 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.
|
|
|
|
// Test that when we pick a trait based on coercion, versus subtyping,
|
|
// we consider all possible coercions equivalent and don't try to pick
|
|
// a best one.
|
|
|
|
trait Object { }
|
|
|
|
trait foo {
|
|
fn foo(self) -> int;
|
|
}
|
|
|
|
impl foo for Box<Object+'static> {
|
|
fn foo(self) -> int {1}
|
|
}
|
|
|
|
impl foo for Box<Object+Send> {
|
|
fn foo(self) -> int {2}
|
|
}
|
|
|
|
fn test1(x: Box<Object+Send+Sync>) {
|
|
// Ambiguous because we could coerce to either impl:
|
|
x.foo(); //~ ERROR E0034
|
|
}
|
|
|
|
fn test2(x: Box<Object+Send>) {
|
|
// Not ambiguous because it is a precise match:
|
|
x.foo();
|
|
}
|
|
|
|
fn test3(x: Box<Object+'static>) {
|
|
// Not ambiguous because it is a precise match:
|
|
x.foo();
|
|
}
|
|
|
|
fn main() { }
|