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// 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.
// ignore-pretty FIXME(#14193)
#![feature(managed_boxes)]
// Test cyclic detector when using trait instances.
use std::cell::RefCell;
struct Tree(@RefCell<TreeR>);
struct TreeR {
left: Option<Tree>,
right: Option<Tree>,
val: Box<to_str+Send>
}
trait to_str {
fn to_str_(&self) -> String;
}
impl<T:to_str> to_str for Option<T> {
fn to_str_(&self) -> String {
match *self {
None => { "none".to_string() }
Some(ref t) => format!("some({})", t.to_str_()),
}
}
}
impl to_str for int {
fn to_str_(&self) -> String {
self.to_str()
}
}
impl to_str for Tree {
fn to_str_(&self) -> String {
let Tree(t) = *self;
let this = t.borrow();
let (l, r) = (this.left, this.right);
let val = &this.val;
format!("[{}, {}, {}]", val.to_str_(), l.to_str_(), r.to_str_())
}
}
fn foo<T:to_str>(x: T) -> String { x.to_str_() }
pub fn main() {
let t1 = Tree(@RefCell::new(TreeR{left: None,
right: None,
val: box 1 as Box<to_str+Send>}));
let t2 = Tree(@RefCell::new(TreeR{left: Some(t1),
right: Some(t1),
val: box 2 as Box<to_str+Send>}));
let expected =
"[2, some([1, none, none]), some([1, none, none])]".to_string();
assert!(t2.to_str_() == expected);
assert!(foo(t2) == expected);
{
let Tree(t1_) = t1;
let mut t1 = t1_.borrow_mut();
t1.left = Some(t2); // create cycle
}
}
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