1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![feature(managed_boxes)]
13 // Test cyclic detector when using trait instances.
15 use std::cell::RefCell;
17 struct Tree(@RefCell<TreeR>);
25 fn to_str_(&self) -> String;
28 impl<T:to_str> to_str for Option<T> {
29 fn to_str_(&self) -> String {
31 None => { "none".to_string() }
32 Some(ref t) => format_strbuf!("some({})", t.to_str_()),
38 fn to_str_(&self) -> String {
39 self.to_str().to_string()
43 impl to_str for Tree {
44 fn to_str_(&self) -> String {
46 let this = t.borrow();
47 let (l, r) = (this.left, this.right);
49 format_strbuf!("[{}, {}, {}]",
56 fn foo<T:to_str>(x: T) -> String { x.to_str_() }
59 let t1 = Tree(@RefCell::new(TreeR{left: None,
61 val: box 1 as Box<to_str:Send>}));
62 let t2 = Tree(@RefCell::new(TreeR{left: Some(t1),
64 val: box 2 as Box<to_str:Send>}));
66 "[2, some([1, none, none]), some([1, none, none])]".to_string();
67 assert!(t2.to_str_() == expected);
68 assert!(foo(t2) == expected);
72 let mut t1 = t1_.borrow_mut();
73 t1.left = Some(t2); // create cycle